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Meat consumption and risk of colorectal cancer in Japan: The Miyagi Cohort Study
Abstract
The association between meat consumption and risk of colorectal cancer has been controversial. We examined this question in a large prospective cohort study in Japan. From June through August 1990, 47,605 residents, aged 40-64 years, of Miyagi Prefecture in northern Japan completed a self-administered questionnaire, including a food frequency questionnaire. In the study population, we observed 474 incident cases of colorectal cancer during 11 years of follow-up, to March 2001. We used the Cox proportional hazards model to estimate the relative risk of colorectal cancer (colorectum, colon, rectum and proximal colon and distal colon) according to each of the categories of meat intake (total meat, beef, pork, ham or sausage, chicken and liver), with adjustment for sex, age and other potentially confounding variables. The multivariate relative risk of colorectal cancer in the highest category of total meat consumption compared with the lowest was 1.14 [95% confidence interval (CI)=0.85-1.53; P-trend=0.22]. We also found no significant association between total meat consumption and the risk of sub-site of colorectal cancer. In conclusion, our data do not support the hypothesis that meat consumption is a risk factor for colorectal cancer.
... Of the human studies discussed above, 17 studies investigated nitrite-containing processed meats (Table 4). Five studies found nitrite-containing processed meats to have no effect on CRC [43,56,57,59,62] and one study found nitrite-containing processed meat was protective [80]. In contrast, a total of 11 studies found that nitrite-containing processed meat increases the risk of CRC [34][35][36][37][38][39]42,45,48,49,53]. ...
... Of the prospective studies discussed (n = 5), three used the International Classification of Diseases criteria to confirm that the participant met the conditions of a positive diagnosis of CRC [49,57,59]; two studies did not specify which criteria they used. Wu et al. [48] consulted the patients' medical records. ...
... The FFQs varied in design and detail. Three studies recorded information on portion size [43,45,57], and the remainder did not. Researchers invited participants to describe their consumption habits in a number of ways, Dales et al. [62] included eight different frequencies, ranging from "never" to "at least once a day." ...
The World Cancer Research Fund (WCRF) 2007 stated that the consumption of processed meat is a convincing cause of colorectal cancer (CRC), and therefore, the public should avoid it entirely. Sodium nitrite has emerged as a putative candidate responsible for the CRC-inducing effects of processed meats. Sodium nitrite is purported to prevent the growth of Clostridium botulinum and other food-spoiling bacteria, but recent, contradictory peer-reviewed evidence has emerged, leading to media reports questioning the necessity of nitrite addition. To date, eleven preclinical studies have investigated the effect of consuming nitrite/nitrite-containing meat on the development of CRC, but the results do not provide an overall consensus. A sizable number of human clinical studies have investigated the relationship between processed meat consumption and CRC risk with widely varying results. The unique approach of the present literature review was to include analysis that limited the human studies to those involving only nitrite-containing meat. The majority of these studies reported that nitrite-containing processed meat was associated with increased CRC risk. Nitrite consumption can lead to the formation of N-nitroso compounds (NOC), some of which are carcinogenic. Therefore, this focused perspective based on the current body of evidence links the consumption of meat containing nitrites and CRC risk.
... (6,7) Six prospective cohort studies have been conducted and obtained different results. (8)(9)(10)(11)(12)(13) Among them, only three studies on the incidence of colorectal cancer, including our previous report, (8) have estimated the quantity of meat consumption using a validated food frequency questionnaire (FFQ), and considered several possible lifestyle confounders. (8)(9)(10) In 2006, in the Takayama study, we reported an association between high consumption of processed meat and an increased risk of colon cancer identified by hospital records of colonoscopy among men after 8 years of follow-up. ...
... (8)(9)(10)(11)(12)(13) Among them, only three studies on the incidence of colorectal cancer, including our previous report, (8) have estimated the quantity of meat consumption using a validated food frequency questionnaire (FFQ), and considered several possible lifestyle confounders. (8)(9)(10) In 2006, in the Takayama study, we reported an association between high consumption of processed meat and an increased risk of colon cancer identified by hospital records of colonoscopy among men after 8 years of follow-up. (8) Since then, we have collected additional information from the cancer registry in the study area. ...
... (11)(12)(13) Three other Japanese cohort studies have estimated the incidence of colorectal cancer. (8)(9)(10) Firstly, the Miyagi cohort study revealed no significant association with total, red, or processed meat consumption. (10) Secondly, the Japan Public Health Center-based prospective study reported that the HR of colon cancer for the highest versus lowest quintiles of red meat intake was 1.48 (95% CI: 1.01, 2.17, P for linear trend = 0.03) in women. ...
Compared with the abundant data from Western countries, evidence regarding meat consumption and colorectal cancer is limited in the Japanese population. We evaluated colorectal cancer risk in relation to meat consumption in a population-based prospective cohort study in Japan. Participants were 13,957 men and 16,374 women aged ≥35 years in September 1992. Meat intake, assessed with a validated food frequency questionnaire, was controlled for the total energy intake. The incidence of colorectal cancer was confirmed through regional population-based cancer registries and histological identification from colonoscopy in two main hospitals in the study area. From September 1992 to March 2008, 429 men and 343 women developed colorectal cancer. After adjustments for multiple confounders, a significantly increased relative risk of colorectal cancer was observed in the highest vs. lowest quartile of the intake of total and red meat among men; the estimated hazard ratios were 1.36 (95% CI: 1.03,1.79) for total meat (p for trend=0.022), and 1.44 (95% CI: 1.10, 1.89) for red meat (p for trend=0.009). A positive association between processed meat intake and colon cancer risk was also observed in men. There was no significant association between colorectal cancer and meat consumption in women. These results suggest that the intake of red and processed meat increases the risk of colorectal or colon cancer among Japanese men. Abstaining from excessive consumption of meat might be protective against developing colorectal cancer. This article is protected by copyright. All rights reserved.
... A total of 6 cohort studies (30 -35) and 13 case -control studies (36 -48) were identified (Supplementary data, Tables S1 and S2, respectively). Of cohort studies, two reported data for men and women combined (30,33), and the remaining ones showed results separately for men and women. Among the case -control studies, nine gave findings for both sexes combined (36 -38,40 -42,44,45,48), two presented results for men and women separately (43,47), and the remainder investigated only men (39,46). ...
... Of total six cohort studies, four showed relative risk for colon and rectum separately (30,32,33,35), but not combined; one reported results for colon cancer only (34), and the remaining study displayed data for both sites combined (31). Of four investigations reporting data for total meat consumption, two displayed a weak-to-moderate positive association with colon cancer (34,35) and one exhibited an inverse association with rectal cancer (30) ( Table 1). ...
... colorectal cancer (31). Some studies found that poultry consumption was weakly, positively associated with colon (32,33) and cancer of both sites (31). ...
Objective:
The association between meat consumption and colorectal cancer remains inconsistent among Asians. The present study systematically evaluated and meta-analyzed epidemiologic studies on the association between consumption of total and specific meats and colorectal cancer risk among Japanese.
Methods:
Original data were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented with manual searches. The associations were evaluated based on the strength of evidence, the magnitude of association and biologic plausibility. A meta-analysis was performed according to total meat, red and processed meat as well as poultry and site-specific cancers.
Results:
Six cohort studies and 13 case-control studies were identified. In cohort studies, most investigations found no association between total meat consumption and colon/rectal cancer, and several studies showed a weak-to-moderate positive association of red meat and processed meat consumption with colon/rectal cancer. The majority of case-control studies showed no association between total meat consumption and colon and rectal cancer; however, several ones reported a weak-to-strong positive association of red and processed consumption with colon and rectal cancer. In meta-analysis, the summary relative risks (95% confidence interval) for the highest versus lowest categories of red meat consumption were 1.16 (1.001-1.34) and 1.21 (1.03-1.43) for colorectal and colon cancer, respectively, and those for processed meat consumption were 1.17 (1.02-1.35) and 1.23 (1.03-1.47) for colorectal and colon cancer, respectively. Poultry consumption was associated with lower risk of rectal cancer; summary relative risk (95% confidence interval) was 0.80 (0.67-0.96).
Conclusions:
High consumption of red meat and processed meat possibly increases risk of colorectal cancer or colon cancer among the Japanese population.
... Following the full-text evaluation, 139 articles were excluded for the reasons indicated in Figure 1, and 32 articles were included in the review. Of these, seven gave data on (red) meat [30][31][32][33][34][35][36], five on processed meat [31][32][33][34][35], eight on fiber [37][38][39][40][41][42][43][44], one on garlic [37], three on milk [45][46][47], seven on calcium [28,45,[47][48][49][50][51], and ten on alcohol [27,29,36,[52][53][54][55][56][57][58]. ...
... Following the full-text evaluation, 139 articles were excluded for the reasons indicated in Figure 1, and 32 articles were included in the review. Of these, seven gave data on (red) meat [30][31][32][33][34][35][36], five on processed meat [31][32][33][34][35], eight on fiber [37][38][39][40][41][42][43][44], one on garlic [37], three on milk [45][46][47], seven on calcium [28,45,[47][48][49][50][51], and ten on alcohol [27,29,36,[52][53][54][55][56][57][58]. ...
... Seven cohort studies were included in the review, of which five reported on red meat [30][31][32][33]35], one on beef and pork [34], and one on meat (not further specified) [36]. The five studies on red meat reported an increased risk of colorectal cancer with increasing intake [30][31][32][33]35] (Table 2) (1) reviews (5) meta-analysis or pooled analysis (2) randomised trials (16) case-control studies Reasons for exclusion after full-text review although most of the risk estimates were not statistically different from unity. ...
Objective. A shift in the total incidence from left- to right-sided colon cancer has been reported and raises the question as to whether lifestyle risk factors are responsible for the changing subsite distribution of colon cancer. The present study provides a review of the subsite-specific risk estimates for the dietary components presently regarded as convincing or probable risk factors for colorectal cancer: red meat, processed meat, fiber, garlic, milk, calcium, and alcohol. Methods. Studies were identified by searching PubMed through October 8, 2012 and by reviewing reference lists. Thirty-two prospective cohort studies are included, and the estimates are compared by sex for each risk factor. Results. For alcohol, there seems to be a stronger association with rectal cancer than with colon cancer, and for meat a somewhat stronger association with distal colon and rectal cancer, relative to proximal colon cancer. For fiber, milk, and calcium, there were only minor differences in relative risk across subsites. No statement could be given regarding garlic. Overall, many of the subsite-specific risk estimates were nonsignificant, irrespective of exposure. Conclusion. For some dietary components the associations with risk of cancer of the rectum and distal colon appear stronger than for proximal colon, but not for all.
... Since then, new results from ten prospective studies [19][20][21][22][23][24][25][26][27][28] have been published. This included studies in Asian populations [20,25,27,28], a Canadian breast cancer screening cohort [24], a US multi-ethnic cohort [26], and four American cohorts [19,[21][22][23].We have focused our review on prospective studies, because case-control studies are more liable to recall and selection bias, and randomized controlled trials on red and processed meats and colorectal cancer are considered not feasible. ...
... Since then, new results from ten prospective studies [19][20][21][22][23][24][25][26][27][28] have been published. This included studies in Asian populations [20,25,27,28], a Canadian breast cancer screening cohort [24], a US multi-ethnic cohort [26], and four American cohorts [19,[21][22][23].We have focused our review on prospective studies, because case-control studies are more liable to recall and selection bias, and randomized controlled trials on red and processed meats and colorectal cancer are considered not feasible. The data on the relation of red and processed meats and colorectal cancers are summarized in highest versus lowest meta-analyses. ...
... Eighteen studies were included in the highest versus lowest meta-analyses [18,[20][21][22][26][27][28]33,34,49,50,52,54,56,57,60,62,64,65]. Processed meat intake was significantly related to the risk of colorectal (RR highest vs lowest = 1.17, 95% CI = 1.0921.25), ...
The evidence that red and processed meat influences colorectal carcinogenesis was judged convincing in the 2007 World Cancer Research Fund/American Institute of Cancer Research report. Since then, ten prospective studies have published new results. Here we update the evidence from prospective studies and explore whether there is a non-linear association of red and processed meats with colorectal cancer risk.
Relevant prospective studies were identified in PubMed until March 2011. For each study, relative risks and 95% confidence intervals (CI) were extracted and pooled with a random-effects model, weighting for the inverse of the variance, in highest versus lowest intake comparison, and dose-response meta-analyses. Red and processed meats intake was associated with increased colorectal cancer risk. The summary relative risk (RR) of colorectal cancer for the highest versus the lowest intake was 1.22 (95% CI = 1.11-1.34) and the RR for every 100 g/day increase was 1.14 (95% CI = 1.04-1.24). Non-linear dose-response meta-analyses revealed that colorectal cancer risk increases approximately linearly with increasing intake of red and processed meats up to approximately 140 g/day, where the curve approaches its plateau. The associations were similar for colon and rectal cancer risk. When analyzed separately, colorectal cancer risk was related to intake of fresh red meat (RR(for 100 g/day increase) = 1.17, 95% CI = 1.05-1.31) and processed meat (RR (for 50 g/day increase) = 1.18, 95% CI = 1.10-1.28). Similar results were observed for colon cancer, but for rectal cancer, no significant associations were observed.
High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers. The overall evidence of prospective studies supports limiting red and processed meat consumption as one of the dietary recommendations for the prevention of colorectal cancer.
... Among the study populations from included studies, 13 were from the United States (US) [27][28][29][30][31][32][33][34][35][36][37][38][39], 11 were from Europe [40][41][42][43][44][45][46][47][48][49][50], 4 were from Asia [51][52][53][54], and 1 was from Australia [55] ( Table 1). The publication year ranged from 1990 to 2015. ...
... Only two of those adjusted for fiber and physical activity [35,36]. Among all the included studies, only ten studies adjusted for socioeconomic status (education) [30,31,34,37,42,43,45,49,52,54]. ...
The objective was to use accumulated evidence to explore the association between processed meat intake and risk of colorectal cancer (CRC) and to investigate the reliability of associations by evaluating patterns of risk by study population characteristics and research quality parameters. We included 29 observational prospective cohort studies with relative risk estimates and 95% confidence intervals for CRC according to various levels of processed meat consumption. Risk of bias was assessed using Risk Of Bias In Non-randomized Studies—of Interventions (ROBINS-I) tool. Data sources were PubMed and Embase up to January 2017. The summary relative risks for high versus low processed meat consumption and risk of CRC, colon, and rectal cancer were 1.13 (95% CI: 1.01, 1.26), 1.19 (95% CI: 1.09, 1.31), and 1.21 (95% CI: 0.98, 1.49), respectively. Similar estimates were observed for the dose-response analyses. Heterogeneity across studies was detected in most analytical models. The overall judgment showed that two out of 29 studies had a moderate risk of bias, 25 had a serious risk of bias, and 2 had a critical risk of bias. The bias domains most often rated critical were bias due to risk of confounding, bias due to missing data, and selective outcome reporting bias. Although this meta-analysis indicates a modest association between processed meat intake and an increased risk of CRC, our assessment of internal validity warrants a cautious interpretation of these results, as most of the included studies were judged to have serious or critical risks of bias.
... 59 A study performed in Japan concluded that higher consumption of processed meat significantly affected men, not women. 86,87 There are some studies that found no association between food consumption and risk of CRC in China, 88 Japan, 89,90 and Singapore. 91 The Ohsaki cohort study indicated that a Japanese dietary pattern had no association with CRC risk. ...
... 68 A study conducted in Malaysia supported that performing regular physical activity could prevent CRC, 72 although the finding was not echoed by a study among Chinese individuals. 89 ...
Globally, colorectal cancer (CRC) is a substantial public health burden, and it is increasingly affecting populations in Asian countries. The overall prevalence of CRC is reported to be low in Asia when compared with that in Western nations, yet it had the highest number of prevalent cases. This review described the prevalence of CRC in Asia according to the International Agency for Research on Cancer from World Health Organization (WHO) database and summarized its major risk factors. Non-modifiable factors include genetic factors, ethnicity, age, gender, family history and body height; smoking, alcohol drinking, weight, Westernized diet, physical inactivity, chronic diseases and microbiota were involved in environmental factors. These risk factors were separately discussed in this review according to published literature from Asian countries. CRC screening has been playing an important role in reducing its disease burden. Some recommendations on its screening practices have been formulated in guidelines for Asia Pacific countries.
... As the authors evaluated colon and rectal cancer separately beside CRC, new data support the existence of two categories of CRC based on site of origin. 2 The aim of this meta-analysis is essentially to summarize and quantify the associations between meat subtypes and CRC. 1 But, when we look at the Sato's study, not only for meat subtypes but also there is not any significant association between total meat consumption and the risk of CRC. 3 Because, the meat consumption is very low in the participants of this study; 70.4 g/day for highest quartile, which is the upper limit of recommended level (500 g/week) for healthy people according to guidelines. 4 So, I think that it is questionable to take this type of completely negative study into specific meta-analyses. ...
... In addition, Figure 3 contains some minor different data than those of original publications such as upper limits of confidence intervals (CIs) in Norat's and Sato's articles, respectively; 1.47 for colorectal cancer and 2.63 (for colon), 1.41 (for rectal) should be 1.48 and 2.62, 1.42 according to the original data. 3,5 Finally, it seems that the relative risk (RR) for colorectal cancer in the Netherlands cohort study, 6 RRs for colon and rectal cancer in Takachi's article 7 were calculated from pooled data mentioned in material and methods. But, RRs for colon and rectal cancer separately from Norat's study which is the largest European cohort study (EPIC) were not included into Figure 2 and 3. ...
... Thus, if the potential carcinogenic effect of red meat is driven by heme iron, the risk might vary according to red meat subtype. Individual associations between specific red meat subtypes (e.g., beef and pork) and risks for colon and rectal cancer have, however, been evaluated in only 3 previous prospective studies, which gave conflicting results (8)(9)(10). In addition to heme iron, exogenously formed NOCs in processed meat and compounds created by cooking of meat, including heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAH), offer further potential underlying biological mechanisms (11,12). ...
... The Netherlands Cohort Study suggested that intake of beef was related to a higher risk for colon cancer and intake of pork to a lower risk (9). No association with beef or pork intake and colon cancer risk was reported in a Japanese cohort study; however, the very low meat consumption of the participants might explain this unexpected finding (8). In the EPIC study (10), a significantly higher risk for colorectal cancer was found for participants in the group with the highest intake of pork and a positive association with lamb consumption was suggested; no association was found with beef or veal consumption. ...
Cancer prevention guidelines recommend limiting intake of red meat and avoiding processed meat; however, few studies have been conducted on the effects of specific red meat subtypes on colon cancer or rectal cancer risk. The study aim was to evaluate associations between intake of red meat and its subtypes, processed meat, fish, and poultry and risk for colon cancer or rectal cancer in the Danish Diet, Cancer and Health cohort study. We also evaluated whether fish or poultry should replace red meat intake to prevent colon cancer or rectal cancer. During follow-up (13.4 y), 644 cases of colon cancer and 345 cases of rectal cancer occurred among 53,988 participants. Cox proportional hazards models were used to compute incidence rate ratio (IRRs) and 95% CIs. No associations were found between intake of red meat, processed meat, fish, or poultry and risk for colon cancer or rectal cancer. The risk associated with specific red meat subtypes depended on the animal of origin and cancer subsite; thus, the risk for colon cancer was significantly elevated for higher intake of lamb [IRR(per 5g/d) = 1.07 (95% CI: 1.02-1.13)], whereas the risk for rectal cancer was elevated for higher intake of pork [IRR(per 25g/d) = 1.18 (95% CI: 1.02-1.36)]. Substitution of fish for red meat was associated with a significantly lower risk for colon cancer [IRR(per 25g/d) = 0.89 (95% CI: 0.80-0.99)] but not rectal cancer. Substitution of poultry for red meat did not reduce either risk. This study suggests that the risks for colon cancer and potentially for rectal cancer differ according to the specific red meat subtype consumed.
... Meat is not homogeneous but varying in its composition along different categories of meat cuts and types of meat (Cosgrove, Flynn, & Kiely, 2005). Despite its generally high nutritional value, elevated levels of meat and processed meat products' consumption have been associated to the prevalence of specific unfavourable health conditions such as some types of cancers (Demeyer, Honikel, & De Smet, 2008;Linseisen et al., 2004;Sato et al., 2006) and diabetes (Schultze, Manson, Willet, & Hu, 2003). In response to the numerous (and often contradictory) scientific reports relating specific foods to health outcomes (Alexander, Cushing, Lowe, Sceurman, & Roberts, 2009;Balder, Goldbohm, & van den Brandt, 2005;Chan, Wang, & Holley, 2007;Larsson, Bergkvist, & Wolk, 2006;Lüchtenborg et al., 2005;Norat et al., 2005;Sato et al., 2006), recommendations for a healthy diet encourage to "limit the intake of red meat and avoid processed meat" (World Cancer Research Fund, 2007). ...
... Despite its generally high nutritional value, elevated levels of meat and processed meat products' consumption have been associated to the prevalence of specific unfavourable health conditions such as some types of cancers (Demeyer, Honikel, & De Smet, 2008;Linseisen et al., 2004;Sato et al., 2006) and diabetes (Schultze, Manson, Willet, & Hu, 2003). In response to the numerous (and often contradictory) scientific reports relating specific foods to health outcomes (Alexander, Cushing, Lowe, Sceurman, & Roberts, 2009;Balder, Goldbohm, & van den Brandt, 2005;Chan, Wang, & Holley, 2007;Larsson, Bergkvist, & Wolk, 2006;Lüchtenborg et al., 2005;Norat et al., 2005;Sato et al., 2006), recommendations for a healthy diet encourage to "limit the intake of red meat and avoid processed meat" (World Cancer Research Fund, 2007). Most recently, Micha, Wallace, and Mozaffarian (2010) concluded from a systematic review and meta-analysis that the consumption of processed meats, but not red meats, is associated with higher incidence of coronary heart disease and diabetes mellitus. ...
This study uses pork consumption frequency and variety to identify and profile European pork consumer segments. Data (n=1931) were collected in January 2008 in Belgium, Denmark, Germany and Poland. "Non-pork eaters" are profiled as predominantly younger (<35 years) females, with a high likelihood of living single and being underweight (BMI<18.5 kg/m²). Three segments of pork eaters were identified. The "Low variety, Low frequency" segment (17.4%) has a similar profile as the non-pork eaters, though it is a largely non-Polish and non-German segment. The "High variety, High frequency" segment (18.6%) consists mainly of rural, lower educated and overweight or obese (BMI>30 kg/m²) males. The segment "High variety, Medium frequency" (50.1%) includes families and other non-single households, with a profile that matches the overall sample. Their pork consumption is balanced over a wide range of pork cuts and pork meat products. Each segment entails specific challenges for the industry and the public health sector.
... Of the 34 cohort studies included in the report, 20 showed a positive association between red meat consumption and risk for CRC [14-24, 26, 27, 29-32, 34-36]. Fourteen studies investigating the association between red meat consumption and risk for CRC either showed no association or low association which was not statistically significant [25,28,33,[37][38][39][40][41][42][43][44][45][46][47]. An overview of the studies is shown in Table 1. ...
Purpose of the Review
Colorectal cancer is the second most common cause of cancer death in the world. The aim of this review is to provide an update on recent epidemiological studies, the molecular mechanisms involved, and ongoing clinical trials investigating the relationship between red meat consumption and colorectal cancer.
Recent Findings
Evidence in the literature proposes an association between red meat consumption and development of colorectal cancer, and there is some insight with regard to the mechanisms involved.
Summary
Twenty studies of the IARC report (1990–2015) showed that red meat is positively associated with colorectal cancer whereas 14 studies either supported no positive association or no statistically significant association between red meat consumption and risk for CRC. More recent epidemiological studies conducted from 2016 and onwards provided further evidence that adherence to diets low in red and/or processed meat reduces the risk of colorectal cancer. Evidence from recent studies supports that quantity, doneness, and preparation of red meat play a role in colorectal carcinogenesis. Red meat’s degradation products allow for the creation of a pro-inflammatory colonic microenvironment, and the gut microbiome plays a role in colorectal carcinogenesis. Heme, hydrogen sulfide, lipid peroxidation, nitroso compounds, and the bacterium Fusobacterium Nucleatum (as well as possibly other bacteria such as Akkermansia muciniphila, Eubacterium cylindroides, Eubacterium eligens 1 and 2, and Eubacterium rectale 1 and 2) also partake in the process of colorectal carcinogenesis. Several clinical trials are underway investigating the effects of different diets and red meat substitution products on colorectal cancer incidence as well as the underlying molecular mechanisms involved in the process.
... Each study was approved by the relevant institutional ethical review boards. The MIYAGI, 30 ...
Red meat and processed meat have been suggested to increase risk of colorectal cancer (CRC), especially colon cancer. However, it remains unclear whether these associations differ according to meat subtypes or colon subsites. The present study addressed this issue by conducting a pooled analysis of large population-based cohort studies in Japan: 5 studies comprising 232,403 participants (5,694 CRC cases) for analysis based on frequency of meat intake and 2 studies comprising 123,635 participants (3,550 CRC cases) for analysis based on intake quantity. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards model and then pooled using the random effect model. Comparing the highest versus lowest quartile, beef intake was associated with an increased risk of colon cancer in women (pooled HR 1.20, 95% CI 1.01-1.44) and distal colon cancer (DCC) risk in men (pooled HR 1.38, 95% CI 1.08-1.75). Frequent intake of pork was associated with an increased risk of DCC in women (pooled HR 1.44, 95% CI 1.10-1.87) for "3 times/week or more" versus "<1 time/week". Frequent intake of processed red meat was associated with an increased risk of colon cancer in women (pooled HR 1.39, 95% CI 0.97-2.00; p-trend=0.04) for "almost every day" versus "<1 time/week". No association was observed for the chicken consumption. The present findings support that intake of beef, pork (women only), and processed red meat (women only) may be associated with a higher risk of colon (distal colon) cancer in Japanese. This article is protected by copyright. All rights reserved.
... (5) Compared with Western countries, the definition, type, preparation, and cooking methods of processed meat products in Asian countries are significantly different, which may lead to different results from epidemiological studies. Furthermore, many studies showed that intake of white meat and other meats have negative or insignificant associations with mortality RR (Abete et al. 2014;Carr et al. 2016;Gilsing et al. 2015;Larsson and Orsini 2014;Sato et al. 2006). ...
This study aimed to investigate the relationship between meat intake and colorectal cancer risk from an Asian, particularly Korean, perspective. A report by the International Agency for Research on Cancer (IARC) published in 2015 concluded that intake of processed and red meat increases the risk of developing colorectal cancer. We conducted an in-depth analysis of prospective, retrospective, case-control and cohort studies, systematic review articles, and IARC monograph reports, which revealed that the IARC/WHO report weighted the results of studies based in Western countries more and that the correlation between intake of processed meat products and colorectal cancer incidence in Asians is not clearly supported. Among 73 epidemiological studies, approximately 76% were conducted in Western countries, whereas only 15% of studies were conducted in Asia. Furthermore, most studies conducted in Asia showed that processed meat consumption is not related to the onset of cancer. Moreover, there have been no reports showing significant correlation between various factors that directly or indirectly affect colorectal cancer incidence, including processed meat products types, raw meat types, or cooking methods. Further epidemiological studies taking each country’s food culture into consideration are required to reliably elucidate the effects of processed meat product intake, especially on cancer incidence.
... There is also increased awareness that meat may not confer the health benefits once believed. Research has shown that cardiovascular diseases, such as cancer, type 2 diabetes, and obesity are linked to meat intake (28)(29)(30). Indeed, for flexitarians the option of cutting back on meat, rather than abstaining completely, is a practical compromise that could have meaningful implications for environmental sustainability and personal health. ...
A carefully planned vegetarian diet meets nutrition recommendations by providing essential nutrients and lowering levels of saturated fat and cholesterol. Because balanced diets that limit or exclude meat tend to be lower in calories than omnivorous diets, it has been suggested that vegetarian eating patterns may be motivated by weight control. This view has been supported by findings demonstrating that vegetarians have a higher rate of disordered and restrained eating than non-vegetarians. Other findings suggest that weight control is a primary reason identified by adolescents and young adults for eliminating items such as meat and other animal products from their diet. Thus, it has been suggested that vegetarianism may provide a socially acceptable means to control body weight. However, this may be an over-generalization. Vegetarians are a heterogeneous group of individuals with radically different eating habits. Moreover, they are often compared to omnivores who eat meat on a regular basis. These omnivorous eating habits do not represent a growing subset of the population, many of whom are adopting a flexitarian diet that involves only the occasional consumption of meat. The goal of the current paper will be to demonstrate that semi-vegetarians and flexitarians are categorically different from vegans, lacto-ovo-vegetarians, and omnivores and describe the motivations as well as the positive and negative health implications that are associated with dietary patterns that limit the intake of meat. It is important for us to understand the motivations and behaviors that are characteristic of flexitarians in order to develop effective evidence-based strategies to address unhealthy eating behaviors.
... En este sentido, existe información nacional sobre la calidad nutricional de la carne uruguaya (Cabrera et al., 2010;Saadoun y Cabrera, 2013;Cabrera y Saadoun, 2014). Sin embargo, el consumo de carne roja y en particular de carne procesada han enfrentado una serie de contraindicaciones sanitarias adversas, como lo son las enfermedades cardiovasculares (WHO, 2003), algunos tipos de cáncer (Sato et al., 2006) y la diabetes (Schulze et al., 2003). Estas están relacionadas a la contribución de la carne y sus componentes al consumo de grasa, ácidos grasos saturados (AGS), colesterol, sal y otras sustancias que tienen consecuencias negativas para la salud humana (Olmedilla-Alonso et al., 2013). ...
Archivos Latinoamericanos de Producción Animal. Volumen 24(4):2016 1 Investigación para el desarrollo de estrategias nutricionales y genéticas que optimicen el contenido y el perfil de ácidos grasos de la carne vacuna uruguaya. Revisión. Research needs to develop nutritional and genetic strategies that optimize the fatty acid content and profile of Uruguayan beef. Review. Abstract. Health concerns are becoming one of the most relevant predictors for food consumption. Thus, differentiation of the meat product through its nutritional quality plays a key role to improve market competition. This article presents: (1) the nutritional importance of lipids in beef and its relevance for the consumer, (2) scientific information about the characterization of the fatty acid composition of Uruguayan beef, and the incidence of the factors that affect its composition, and (3) areas where more scientific information is needed to reinforce the strategies to improve the nutritional quality of beef. The main production system in Uruguay is based on pastures resulting in beef with lower levels of fat and higher levels of n-3 fatty acids and conjugated linoleic acid. Nonetheless, other production systems involving animal supplementation, are also part of a market diversification strategy. More information is needed to evaluate the impact of our forage diversity (native and improved pastures), the time on feed and the type of supplement on the fatty acid composition of beef. The potential of the genetic progress through selection and genomics or marker assisted selection on the fatty acid composition of beef, also needs further attention to develop effective strategies to capitalize the nutritional value of Uruguayan beef. Resumen. Las preocupaciones por la salud de los consumidores se están convirtiendo en uno de los predictores más relevantes del consumo de alimentos, por lo que la diferenciación del producto carne a través de su calidad nutricional juega un rol importante para mejorar la competitividad en el mercado. Este artículo presenta: (1) la importancia nutricional de los lípidos de la carne vacuna y su relevancia para el consumidor, (2) información científica sobre la caracterización de la composición de ácidos grasos de la carne uruguaya y de la incidencia de los factores que afectan su composición y (3) las áreas en las que se necesita generar mayor información científica que fortalezca las estrategias de mejora de la calidad nutricional de la carne. El principal sistema productivo de Uruguay es de base pastoril resultando en una carne con menores niveles de grasa y mayores niveles de ácidos grasos n-3 y de ácido linoleico conjugado. Sin embargo, otros sistemas productivos más intensivos con suplementación animal, también forman parte de una estrategia de diversificación de mercados. Más información es necesaria para evaluar el impacto de nuestra diversidad forrajera (pasturas nativas y mejoradas) y de la duración y tipo de suplementación sobre la composición de ácidos grasos de la carne. El potencial del progreso genético a través de la selección y de la genómica o la selección asistida por marcadores sobre la composición de ácidos grasos de la carne, también requieren mayor atención para desarrollar estrategias que permitan capitalizar el valor nutricional de la carne uruguaya.
... [120][121][122] In some study, the correlation between the red meat consumption and risk of colorectal cancer has been inconsistent. [123] Also, there is evidence that the frequency of red meat intake is more important than total amount of meat consumed for the CRC risk. [124] The meta-analyses of Chao et al. revealed the firm association of colorectal cancer with red meat consumption. ...
Colorectal cancer (CRC) is a very common and lethal disease worldwide. The etiology of the disease includes genetic and environmental factors. Among environmental factors, the dietary habits are considered to be easily changeable regarding preventing the CRC. Although there is still a long road to cover the gaps in knowledge on nutritional determinants and dietary pattern on the CRC risk, several dietary suggestions and goals could be summarized. Diets high in energy, consumption of red meat or processed meat, food with high glycemic index (carbohydrates, snack food, frying fast food, and sugar-sweetened drinks, sweets), exceed intake of salt (NaCl), low daily water intake (< 4 cups per day) have been linked to an increased CRC risk. In contrast, consumption of white meat, as well as plant and fish oils with a high omega-3 PUFAs to omega-6 PUFAs ratio might even reduce the occurrence of CRC. A fiber-rich diet can lower the CRC risk up to 50%. Diet rich in vitamin B6, C, D, E, folic acid, selenium, and magnesium has also been considered to reduce the CRC risk. General unhealthy lifestyle which results in overweight and obesity-related syndromes (chronic inflammation, type 2 diabetes) can promote CRC. However, in many cases, the results are inconsistent and depend on multiple interdependent factors, i.e., ethnic, anthropometric, gender, age, hormonal, environmental. In addition to dietary habits, all these agents are suggested to modify the risk of CRC.
... The first Japanese study published by Sato and his colleagues, in 2006. 28 They concluded that not only any type of red meat, but also total red meat consumption was not a risk factor for CRC. When we look at carefully to Sato's study, we see that the meat consumption is very low in the participants of this study; 70.4 g/day for highest quartile, which is the upper limit of recommended level for healthy people according to the guidelines, mentioned below. ...
Colorectal cancer (CRC) is the third most common cancer in men and the second in women worldwide. More than half of cases occur in more developed countries. The consumption of red meat (beef, pork, lamb, veal, mutton) is high in developed countries and accumulated evidence until today demonstrated a convincing association between the intake of red meat and especially processed meat and CRC risk. In this review, meta-analyses of prospective epidemiological studies addressed to this association, observed link of some subtypes of red meat with CRC risk, potential carcinogenic compounds, their mechanisms and actual recommendations of international guidelines are presented.
... Red and processed meat consumption have been associated with an increased risk of CRC in many observational studies and thus reducing, or eliminating, their intake may prevent CRC development [2][3][4][5]. Yet the impact of these meats on CRC risk may depend on the time in one's life when meat is consumed [6][7][8][9] and meat consumption may impact cancer development differently across the three regions of the colorectum (proximal colon, distal colon, or rectum) [10][11][12][13][14][15]. To date, however, evidence on the relation between red meat and CRC risk by subsite location and time of intake has been limited. ...
Although the association between red meat consumption and colorectal cancer (CRC) is well established, the association across subsites of the colon and rectum remains uncertain, as does time of consumption in relation to cancer development. As these relationships are key for understanding the pathogenesis of CRC, they were examined in two large cohorts with repeated dietary measures over time, the Nurses' Health Study (n = 87,108 women, 1980-2010) and Health Professionals Follow-up Study (n = 47,389 men, 1986-2010). Cox proportional hazards regression models generated hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled by random-effects meta-analysis. In combined cohorts, there were 2,731 CRC cases (1,151 proximal colon, 816 distal colon, and 589 rectum). In pooled analyses, processed red meat was positively associated with CRC risk (per 1 serving/day increase: HR = 1.15, 95% CI: 1.01-1.32; P for trend 0.03) and particularly with distal colon cancer (per 1 serving/day increase; HR = 1.36; 95% CI: 1.09-1.69; P for trend 0.006). Recent consumption of processed meat (within the past 4 years) was not associated with distal cancer. Unprocessed red meat was inversely associated with risk of distal colon cancer and a weak non-significant positive association between unprocessed red meat and proximal cancer was observed (per 1 serving/day increase: distal HR = 0.75; 95% CI: 0.68-0.82; P for trend
... In western countries, some studies have shown that high intake of meat may increase the risk of colorectal cancer (Larsson et al., 2005;Norat et al., 2005). However, some studies in Japan did not show clear associations between colorectal cancer, colon cancer and rectal cancer (Kojima et al., 2004;Sato et al., 2006). Similar to studies in Japan, the mean intake of meat did not differ between cases and controls. ...
Colorectal cancer is one of the most commonly occurring cancers in China. Dietary fibre has been thought to decrease the risk of colorectal cancer in Western countries. However, studies investigating the association between dietary fibre (particularly soluble and insoluble fibres) and colorectal cancer have hitherto been lacking in China.
This case-control study examined the effect of dietary fibre intake on the risk of colorectal cancer, stratified by tumour site.
The study included 265 cases (colon cancer, 105; rectal cancer, 144; colon and rectal cancer, 16) and 252 controls residing in Qingdao. A food frequency questionnaire that included 121 food items was used to collect dietary information. Odds ratio (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression analysis.
For food groups, controls in the study consumed more vegetables, soy food and total fibre than did colorectal cancer patients (p<0.05). The intakes of fruit, meat and sea-food did not differ significantly between cases and controls. However, we did not find any association between soy food intake and colon cancer. We observed inverse associations between total fibre intake and colorectal, colon and rectal cancer (Q4 vs Q1: OR=0.44, 95%CI, 0.27- 0.73; OR=0.40, 95%CI, 0.21-0.76; OR=0.52, 95%CI, 0.29-0.91). Vegetable fibre intake showed similar inverse associations (Q4 vs Q1: OR=0.51, 95%CI, 0.31-0.85; OR=0.48, 95%CI, 0.25-0.91; OR=0.53, 95%CI, 0.29-0.97). In addition, inverse associations were observed between soluble fibre and insoluble fibre and both colorectal cancer and colon cancer. No relationship was found between colorectal cancer and fruit, soy or grain fibre intakewhen the results were stratified by tumour site.
The present study suggests that vegetable fibre and total fibre play very important roles in protecting against colorectal cancer. Soluble and insoluble fibres were inversely associated with only colorectal cancer and colon cancer.
... Finally, the correspondent addresses an important point. The confidence limits reported for the studies by Norat et al. 3 and by Sato et al. 4 were not transferred correctly into Figure 3. We sincerely apologize to the authors of the two studies for this unnecessary mistake. ...
Associations between specific red meat subtypes and risk of colorectal cancer (CRC) have been investigated in a number of epidemiological studies. However, no publication to date has summarised the overall epidemiological evidence.We conducted a systematic review and meta-analysis of prospective studies (cohort, nested case-control or case-cohort studies) which reported relative risk (RR) estimates and 95% confidence intervals (CI) for the association between intake of meat subtypes with colorectal, colon or rectal cancer, or colorectal adenoma risk. PubMed and ISI Web of Science were searched up until 1 August 2014. Nineteen studies examined meat subtypes (5 beef, 5 pork, 2 lamb, 1 veal, 19 poultry) and associations with colorectal, colon or rectal cancer risk, and 4 studies examined associations with adenoma risk (1 beef, 4 poultry). Comparing highest versus lowest intake, beef consumption was associated with an increased risk of CRC (RR=1.11, 95% CI=1.01 to 1.22) and colon cancer (RR=1.24, 95% CI=1.07 to 1.44), but no association was found with rectal cancer (RR=0.95, 95% CI=0.78 to 1.16). Higher consumption of lamb was also associated with increased risk of CRC (RR=1.24, 95% CI=1.08 to 1.44). No association was observed for pork (RR=1.07, 95% CI=0.90 to 1.27), but some between study heterogeneity was observed. No association was observed for poultry consumption and risk of colorectal adenomas or cancer.This meta-analysis suggests that red meat subtypes differ in their association with CRC and its sub sites. Further analysis of data from prospective cohort studies is warranted, especially regarding the role of pork. This article is protected by copyright. All rights reserved.
... Our results did not show any association between red meat consumption and CRC risk, but such an association was found for the frequency of intake of chicken. The lack of an association between red meat intake and CRC has also been reported in several studies conducted in Japan (Oba et al., 2006;Sato et al., 2006) and in China (Lee et al., 2009). The lack of an association between red meat intake and CRC in our study may be related to the overall low consumption of red meat by our participants. ...
The role of diet in colorectal cancer (CRC) in Jordan was not studied previously. This study aimed at examining the association between food groups (including grains, fruits, vegetables, milk, and meat and legumes) and CRC risk in Jordan. We compared intakes of the different food groups of CRC cases (n=167) and matched controls (n=240) by age, gender, occupation and marital status. A validated food frequency questionnaire was used to collect dietary data. Logistic regression was used to evaluate the association of quartiles of intakes of the different food groups with CRC risk. In addition, the association of selected food items with CRC risk was examined. Odd ratios (ORs) for the fourth vs. first quartile of intake were 2.92 (95% CI: 1.40–6.08) for grains, 1.66 (95% CI: 0.81-3.40) for vegetables, 0.55 (95% CI: 0.26-1.16) for fruits, 0.96 (95% CI: 0.46-1.97) for milk, and 1.43 (95% CI: 0.68-2.98) for meat and legumes. In a comparison of the highest with the lowest weekly frequency of consumption, there was a direct association between risk of CRC and frequency consumption of chicken (OR = 2.52 ( 95% CI: 1.33–4.77). An increase in risk was observed with increased consumption of white bread (OR = 3.13, 95% CI: 1.18–9.25). While consumption of whole bread was associated with decreased risk of CRC (OR =0.32, 95% CI: 0.12–0.84). Our results support a role of diet in CRC. Direct associations were found for grains, white bread, and chicken, while inverse relation was reported for whole bread.
... On the one hand, meat is nutritionally dense, hence an important source of a wide range of nutrients such as proteins, fats and vitamins (Verbeke et al., 2009). Despite a generally high nutritional value, the consumption of meat and processed meat products has been associated with a number of unfavourable health conditions, such as some types of cancer (Sato et al., 2006;Linseinsen et al., 2004) and coronary heart diseases (Kontogianni et al., 2008). Recent recommendations suggest that moderate consumption of fresh red meat and avoidance of processed high fat meat products are desirable for the prevention of colorectal cancers (Demeyer et al., 2008). ...
Processed meats have been under the spotlight, since consumers worldwide are facing a dilemma: how to keep pace with modern life, where the need for convenience, self-indulgence, quality and safety is uttermost, and still preserve naturalness of meat products? In this chapter we explore the consumer's judgement of meat quality and the ongoing trends towards convenience and wellness (health and naturalness). New positioning strategies are suggested for the meat processing sector and opportunities from emerging markets are finally presented.
... Meat and meat products are generally recognized as highly nutritious foods that provide valuable amounts of protein, fatty acids, vitamins, minerals and other bioactive compounds (Olmedilla-Alonso, Jiménez-Colmenero, & Sánchez-Muniz, 2013), and consumers consider meat to be a healthy and important component of the diet (Verbeke, Pérez-Cueto, de Barcellos, Krystallis, & Grunert, 2010). However, red meat and processed meat consumption have been associated with a number of unfavorable health conditions, such as cardiovascular disease (WHO, 2003), some types of cancers (Sato et al., 2006), and diabetes (Schulze, Manson, Willett, & Hu, 2003) linked to the contribution of meat and meat products to the intake of fat, saturated fatty acids, cholesterol, salt, and other substances that may have negative health implications (Olmedilla-Alonso et al., 2013). According to Verbeke et al. (2010), the increased transparency about the nutritional content of food products may also induce changes in consumer demand, and has already led producers to reformulate some meat products with lower fat or higher polyunsaturated fatty acid content. ...
... P for trend 0 0.12). Currently, evidence by proximal and distal colon cancers is relatively limited, but the observed associations are stronger for distal colon cancer [28][29][30][31]. Traditionally, meat consumption was low in Japan, but diet is becoming increasingly westernised. ...
Epidemiological evidence of red meat and processed meat consumption and colorectal cancer risk has accumulated during the past decades. Meta-analyses of case-control and prospective cohort studies have shown a moderate increased risk, but the association is controversial. Because diet is one of the modifiable lifestyle factors for colorectal cancer prevention, the relationship has an important public health perspective. Three prospective cohort studies and one case-control study of total red meat and processed meat and colorectal cancer were published in 2011 and 2012. The findings were in general supportive of an increased risk with higher consumption. The same applies to the four studies each on fresh red meat and processed meat. Associations with dietary heterocyclic amines, nitroso-compounds, and heme iron intake are inconsistent, but evidence suggested a positive association between heme iron intake and colorectal cancer risk.
... Given the trend of increasing meat consumption over time in Asia, a westernized diet heavy in animal products has been invoked as a cause of this increasing incidence and mortality from cancer and CVD (28). However, Asian prospective cohort studies (29)(30)(31)(32)(33), most of which were included in our pooled analysis, have not supported the hypothesis that meat intake is involved in all-cause, cancer, or CVD mortality, unlike the pattern seen in Europe and North America (5,6,34,35). ...
Total or red meat intake has been shown to be associated with a higher risk of mortality in Western populations, but little is known of the risks in Asian populations.
We examined temporal trends in meat consumption and associations between meat intake and all-cause and cause-specific mortality in Asia.
We used ecological data from the United Nations to compare country-specific meat consumption. Separately, 8 Asian prospective cohort studies in Bangladesh, China, Japan, Korea, and Taiwan consisting of 112,310 men and 184,411 women were followed for 6.6 to 15.6 y with 24,283 all-cause, 9558 cancer, and 6373 cardiovascular disease (CVD) deaths. We estimated the study-specific HRs and 95% CIs by using a Cox regression model and pooled them by using a random-effects model.
Red meat consumption was substantially lower in the Asian countries than in the United States. Fish and seafood consumption was higher in Japan and Korea than in the United States. Our pooled analysis found no association between intake of total meat (red meat, poultry, and fish/seafood) and risks of all-cause, CVD, or cancer mortality among men and women; HRs (95% CIs) for all-cause mortality from a comparison of the highest with the lowest quartile were 1.02 (0.91, 1.15) in men and 0.93 (0.86, 1.01) in women.
Ecological data indicate an increase in meat intake in Asian countries; however, our pooled analysis did not provide evidence of a higher risk of mortality for total meat intake and provided evidence of an inverse association with red meat, poultry, and fish/seafood. Red meat intake was inversely associated with CVD mortality in men and with cancer mortality in women in Asian countries.
... Of seven papers identified in a systematic search on colorectal cancer risk, five found a protective association with increased chicken consumption (26)(27)(28)(29)(30) , one found no association (31) , while another found a positive association between cooking method for chicken (i.e. preferring darkly browned surfaces) and cancer risk (32) . ...
... Unexpectedly, greater intakes of unprocessed poultry were associated with a reduced risk for total colorectal, total colon, proximal colon, and rectal tumors. Several past prospective cohort studies have reported similar inverse associations between poultry and colorectal cancer (8,35,36,44), although a number of others have reported either null (34,(45)(46)(47) or positive associations (48)(49)(50). One reason for these findings could be that poultry, compared to red meat, contains lower amounts of heme, and heme stimulates the production of endogenous NOCs in the gastrointestinal tract (51). ...
Since meat may be involved in the etiology of colorectal cancer, associations between meat-related compounds were examined to elucidate underlying mechanisms in a population-based case-control study. Participants (989 cases/1,033 healthy controls) completed a food frequency questionnaire with a meat-specific module. Multivariable logistic regression was used to examine associations between meat variables and colorectal cancer; polytomous logistic regression was used for subsite-specific analyses. The following significant positive associations were observed for meat-related compounds: 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and colorectal, distal colon, and rectal tumors; 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and colorectal and colon cancer tumors; nitrites/nitrates and proximal colon cancer; 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and rectal cancer; and benzo[a]pyrene and rectal cancer (P-trends < 0.05). For analyses by meat type, cooking method, and doneness preference, positive associations between red processed meat and proximal colon cancer and pan-fried red meat and colorectal cancer were found (P-trends < 0.05). Inverse associations were observed between unprocessed poultry and colorectal, colon, proximal colon, and rectal tumors; grilled/barbequed poultry and proximal colon cancer; and well-done/charred poultry and colorectal, colon, and proximal colon tumors (P-trends < 0.05). HCAs, PAHs, nitrites, and nitrates may be involved in colorectal cancer etiology. Further examination into the unexpected inverse associations between poultry and colorectal cancer is warranted.
... Diet may also be an important confounding factor [101]. Because of the caloric content of alcoholic beverages, their consumption may displace other foods and nutrients from the diet, especially in heavy drinkers [126, 127]. Several foods and nutrients, such as vegetables, fruits, and carotenoids, potentially decrease the risk of lung cancer [92]. ...
Alcohol abuse is a systemic disorder and increases the risk of lung injury. After ingestion, alcohol freely dif-fuses from the bronchial circulation directly through the ciliated epithelium where it vaporizes as it moves into the con-ducting airways. Some of vaporized alcohol can deposit back into the airway lining fluid and results in repeated exposure of the airway epithelium to high local concentrations of alcohol. Chronic alcohol ingestion is associated with increased renin-angiotensin system, induces oxidative stress through angiotensin (Ang) II stimulated NADPH oxidase expression and activity, and superoxide production. Alcohol metabolism within the lung through the cytochrome P 450 system may also be sufficient to exert significant oxidative stress. Alcohol inhibits the expression of GM-CSF and impairs immune system. Chronic ingestion of ethanol altered cellular functions and viability such as decreased surfactant processing, de-creased barrier integrity, increased sensitivity to cytotoxin-induced apoptosis in vitro and in vivo in alveolar type II cells, and decreased phagocytosis of microorganisms in alveolar macrophages. The lung becomes more susceptible when a sec-ond hit such as sepsis occurs. Though dietary supplementation with glutathione precursors or selective Ang II type 2 re-ceptor inhibition limits lung injury in animal model, the most attractive candidate for treating the alcoholic lung in the acute setting is recombinant GM-CSF. Whether any of these therapeutic strategies will prove to be effective in decreasing the consequences of alcohol abuse on acute pulmonary diseases is at present unknown.
... Meat is not homogeneous, different cuts and types of meat vary in composition (Cosgrove, Flynn, & Kiely, 2005). Despite its generally high nutritional value, the consumption of meat and processed meat products is associated with a number of unfavourable health conditions, such as some types of cancers (Linseinsen, Rohrmann, Norat, et al., 2004;Sato et al., 2006) and other chronic diseases including diabetes (Schultze, Manson, Willet, & Hu, 2003). Recent recommendations suggest that moderate consumption of fresh red meat and avoidance of processed meat products are desirable for the prevention of colorectal cancers (Demeyer, Honikel, & De Smet, 2008). ...
This paper presents the combined mid-term findings of the consumer research components of two EU Sixth Framework Programme integrated projects concerning meat, ProSafeBeef and Q-PorkChains. The consumer pillar of ProSafeBeef carried out eight focus group discussions in May 2008, in France, Germany, Spain and the UK. Q-PorkChains conducted a large-scale, web-based, consumer survey in January 2008 in Belgium, Denmark, Germany, Greece and Poland. The first project provides a set of qualitative data from a small cohort of focus groups and the second a set of quantitative data from a larger consumer sample. This paper draws together the main findings of both projects and provides a comprehensive overview of European citizens' and consumers' attitudes towards and preferences regarding beef and pork. In general, consumers consider meat to be a healthy and important component of the diet. Consumers support the development of technologies that can improve the health attributes of meat products and guarantee eating quality, but they have a negative view of what they see to be excessive manipulation and lack of naturalness in the production and processing of beef products. In the Q-PorkChains study consumer and citizen segments are identified and profiled. Consumer segments were built upon the frequency and variety of pork consumption. The citizen segments were built upon their attitudes towards pig production systems. Overall, the relationship between individuals' views as citizens and their behavior as consumers was found to be quite weak and did not appear to greatly or systematically influence meat-buying habits. Future studies in both projects will concentrate on consumers' acceptance of innovative meat product concepts and products, with the aim of boosting consumer trust and invigorating the European beef and pork industries.
... These changes in animal feeding are relatively recent and may help to account for differences in the literature concerning risks associated with eating red meat (Truswell 2002). Most studies showing harmful effects have come from the USA (Norat et al. 2002;Fung et al. 2003) while studies showing no ill effects are mainly non-American (Mathew et al. 2004;Tiemersma et al. 2004;Sato et al. 2006). ...
Objective:
Dietary conjugated linoleic acids (CLA) have had many health benefits claimed for them, including antineoplastic actions.
Materials and methods:
The effects of the predominant forms of CLA, namely the c9t11 and t10c12 isomers, or a mixture of these on polyp development, were investigated in the Apc(Min/+) mouse. CLAs have also been linked to altered rates of cell renewal and cell proliferation so this was also studied, as was a further means of increasing tissue mass, namely crypt fission.
Results:
The stomach and small intestine were significantly heavier in the t10c12, and in the mixture-treated groups (P < 0.001). Crypt fission was increased in the middle small intestine by the t10c12 diet while colonic weight was reduced by c9t11 provision and crypts were 20% shorter. The t10c12 and the mixture significantly reduced polyp number in the proximal small intestine but they increased polyp diameter in the middle and distal small intestine, to an extent that the polyp burden was significantly increased at these sites. All CLAs significantly reduced polyp number in the colon, but the mixture significantly increased polyp diameter in the colon.
Conclusion:
Increased polyp diameter associated with t10c12 diet and especially with the mixture is a cause of concern, as this is the commercially available form. The naturally occurring isomer, c9t11 decreased colonic polyp number and did not increase diameter, suggesting that this natural isomer is the most likely to be protective.
... To our knowledge, seven studies have independently reported associations between red meat consumption and the risk of proximal or distal colon cancer. 11,[21][22][23][40][41][42] Results have shown a relatively consistent stronger positive association for the distal colon: five studies showed a stronger association for distal than proximal colon cancer 11,21-23,40 among men 21,22 , women 23 , or combined 11,40 ; one showed a stronger association for proximal colon cancer 41 ; and one found no difference for men and women combined. 42 Only a few prospective studies have evaluated the effect of red meat consumption on the risk of subsite-specific colon cancers separately by gender (men 21,22 or women 23 ). ...
Asian populations have changed from traditional to Westernized diets, with increased red meat intake. They are suggested to be particularly susceptible to the adverse effects of red meat on the development of colorectal cancers, however, few prospective studies of this putative link have been conducted. We examined associations between the consumption of red and processed meat and the risk of subsite-specific colorectal cancer by gender in a large Japanese cohort. During 1995-1998, a validated food frequency questionnaire was administered to 80,658 men and women aged 45-74 years. During 758,116 person-years of follow-up until the end of 2006, 1,145 cases of colorectal cancer were identified. Higher consumption of red meat was significantly associated with a higher risk of colon cancer among women [multivariate hazard ratios (95%CIs) for the highest versus lowest quintiles (HR): 1.48 (1.01, 2.17; trend p=0.03)], as was higher consumption of total meat among men [HR=1.44 (1.06, 1.98; trend p=0.07)]. By site, these positive associations were found for the risk of proximal colon cancer among women and for distal colon cancer among men. No association was found between the consumption of processed meat and risk of either colon or rectal cancer. In conclusion, red meat intake may modestly increase the risk of colon cancer in middle-aged Japanese, although the highest quintile of red meat consumption could be considered moderate by Western standards.
... drinks of beverages and grams of ethanol per day were inconsistent) [6]. Thus, the present analyses were based on 59 studies, including 44 case–control and 15 cohort515253545556575859606162636465 studies. For each study, we extracted information on study design, country, number of subjects (cases, controls or cohort size), type of controls and period of enrollment for case–control studies, duration of follow-up for cohort studies, cancer site, sex distribution of the study population, variables adjusted for in the analysis, RR estimates and the corresponding CI and, when available, the number of cases and noncases or person-years for each category of alcohol consumption. ...
Whether an association between alcohol drinking and gastric cancer risk exists is an open question. In order to provide a definite quantification of the association between alcohol drinking and gastric cancer risk, we conducted a meta-analysis of available data.
We carried out a PubMed search of articles published up to June 2010 and identified 44 case-control and 15 cohort studies, including a total of 34 557 gastric cancer cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates. We carried out a dose-risk analysis using nonlinear random-effects meta-regression models.
Compared with nondrinkers, the pooled relative risk (RR) was 1.07 [95% confidence interval (CI) 1.01-1.13] for alcohol drinkers and 1.20 (95% CI 1.01-1.44) for heavy alcohol drinkers (≥4 drinks per day). The pooled estimates were apparently higher for gastric noncardia (RR for heavy drinkers=1.17, 95% CI 0.78-1.75) than for gastric cardia (RR=0.99, 95% CI 0.67-1.47) adenocarcinoma. The dose-risk model estimated a RR of 0.95 (95% CI 0.91-0.99) for 10 g/day and 1.14 (95% CI 1.08-1.21) for 50 g/day.
This meta-analysis provides definite evidence of a lack of association between moderate alcohol drinking and gastric cancer risk. There was, however, a positive association with heavy alcohol drinking.
... Alcohol relative risk estimates are usually computed for different levels of drinking and used to be gender, age and geographic area specific. More recent etiologic case control studies have used the Cox proportional-hazards model to obtain multivariate estimates of relative risk (Nakaya, N. et al., 2005 ; Otani et al., 2003). The empirical literature on alcohol costs, dealing with the relative risk methodology, focus mostly on the burden of disease alcohol abusers impose on society as a whole (Saloma, J., 1995; Brecht et al., 1996; Devlin et al., 1997; Single et al., 1998; Varney and Guest, 2000). ...
Aim: This study estimates alcohol attributable fractions which are used to obtain a measure of health expenditures related to alcohol misuse in Portugal. Methods and Sources: Studies estimating alcohol-attributable expenditures focus usually on specific diseases or conditions. This study takes a broader approach by examining all expenditures considered as being attributable to excessive drinking, i. e., those resulting from utilization directly and indirectly related to alcohol associated diseases. Unlike studies using the relative risk methodology, where population alcoholattributable fractions (or etiologic fractions) are based on epidemiological studies identifying potential causes of death and disease associated with alcohol excessive consumption, this study has adopted the microeconometric methodology which gets estimates of attributable fractions running econometric regressions of the annual costs of medical care (medical appointments or hospital admissions) for individuals. It has an advantage over the risk approach in that it allows to control for the effect of factors other than alcohol consumption on medical care expenditures. Actually, it includes in the analysis those factors that are linked to health care expenditures but are not linked to any particular alcohol related disease. To perform our analysis we have used two data sets provided by the Portuguese Ministry of Health: the 1995 National Health Survey. These surveys provide detailed information on individual demographic, economic, health utilization, health attributes and also alcohol and smoking use. Both surveys use a probabilistic representative sample of the non-institutionalized Portuguese population and a questionnaire of about 180 questions. It is a representative sample of the five main administrative regions of Portugal (North, Centre, Lisbon and Tejo valley, Alentejo and Algarve).
Pork is a frequently consumed red meat that provides substantial amounts of energy, macronutrients, and micronutrients to the diet. Its role in human nutrition and health is controversial and a plethora of data exist in the peer-reviewed scientific literature. Therefore, we conducted a scoping review of clinical and population-based studies to assess the effects of pork consumption on human nutrition and health. Results are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Data were extracted from 86 studies, including 16 randomized controlled trials, 1 uncontrolled trial, 7 cohort studies, 4 nonrandomized controlled trials, 4 case-cohort and nested case-control studies, 33 case-control studies, and 21 cross-sectional studies. Intervention studies were conducted in healthy individuals and were short to moderate in duration. The effect of pork intake on patients’ nutrient status was the most commonly assessed outcome. The majority of observational studies assessed the effect of pork on cancer incidence, but no studies assessed the effects of pork on inflammation or oxidative stress. No interventional studies explored diabetes mellitus risk, and only one study assessed cancer risk associated with pork consumption. Several micronutrients in pork, including zinc, iron, selenium, choline, thiamin, and vitamins B6 and vitamin B12, are thought to influence cognitive function and may prove to be a unique area of research. To date, there is a dearth of high-quality randomized controlled trials assessing the effects of pork intake on disease risk factors and outcomes. This review helps highlight the many research gaps that future studies should be designed to address.
The aim of this study was to perform a meta-analysis to test the association between red, processed, and total meat, as well as fruit and vegetable consumption, and selected health risk factors, including body weight status, smoking habit, physical activity level, level of education, and alcohol drinking in cohort studies on non-communicable disease. A systematic search of electronic databases was performed to identify relevant articles published up to March 2017. In a two-stage approach, frequency-weighted linear regression coefficients were first calculated for each variable, and then combined across studies through meta-regression. Ninety-eight studies including 20 on red meat, 6 on processed meat, 12 on total meat, 37 on fruit and vegetable combined, 21 on fruit and 24 on vegetable consumption were analyzed. Intake of red meat was positively associated with BMI, percentage of overweight and obese, low physical activity, and current and ever smoking and inversely associated with percentage of non-smokers and high physically active individuals. Similar associations were found for red meat were found, although based on fewer data. Intake of fruits and vegetables was positively associated with prevalence of non-smokers, high education and high physical activity, and similar results were found when examining fruit and vegetable consumption separately. Stratification by geographical area revealed that some associations were stronger in US rather than European or Asian cohorts. In conclusions, the distribution of health risk factors associated with high meat and fruit/vegetable consumption may differ from those of low-consumers. Some of these differences may mediate, confound, or modify the relation between diet and non-communicable disease risk.
Objective:
As part of the World Cancer Research Fund International Continuous Update Project, we updated the systematic review and meta-analysis of prospective studies to quantify the dose-response between foods and beverages intake and colorectal cancer risk.
Data sources:
PubMed and several databases up to May 31 st 2015.
Study selection:
Prospective studies reporting adjusted relative risk estimates for the association of specific food groups and beverages and risk of colorectal, colon and rectal cancer.
Data synthesis:
Dose-response meta-analyses using random effect models to estimate summary relative risks (RRs).
Results:
Results: 400 individual study estimates from 111 unique cohort studies were included. Overall, the risk increase of colorectal cancer is 12% for each 100g/day increase of red and processed meat intake (95%CI=4-21%, I2 =70%, pheterogeneity (ph)<0.01) and 7% for 10 g/day increase of ethanol intake in alcoholic drinks (95%CI=5-9%, I2 =25%, ph = 0.21). Colorectal cancer risk decrease in 17% for each 90g/day increase of whole grains (95%CI=11-21%, I2 =0%, ph = 0.30, 6 studies). For each 400 g/day increase of dairy products intake (95%CI=10-17%, I2 =18%, ph = 0.27, 10 studies). Inverse associations were also observed for vegetables intake (RR per 100 g/day =0.98 (95%CI=0.96-0.99, I2 =0%, ph = 0.48, 11 studies) and for fish intake (RR for 100g/day=0.89(95%CI=0.80-0.99, I2 =0%, ph = 0.52, 11 studies), that were weak for vegetables and driven by one study for fish. Intakes of fruits, coffee, tea, cheese, poultry and legumes were not associated with colorectal cancer risk.
Conclusions:
Our results reinforce the evidence that high intake of red and processed meat and alcohol increase the risk of colorectal cancer. Milk and whole grains may have a protective role against colorectal cancer. The evidence for vegetables and fish was less convincing.
Noncommunicable chronic diseases such as inflammatory bowel diseases, cancer, diabetes, obesity, and pulmonary, cardiovascular, and neurodegenerative diseases are becoming the leading cause of death throughout the world. Unhealthy diet, smoking, lack of exercise, stress, radiation exposure, and environmental pollution are among the common causes of chronic diseases. Most of these risk factors are closely linked to chronic inflammation, which leads to the development of various chronic diseases. Diets high in fruits, vegetables, legumes, fiber, and certain spices have been shown to suppress chronic inflammation and prevent the development of chronic diseases. In this review we discuss the evidence for the molecular basis of inflammation and how inflammation mediates most chronic diseases. We also present clinical and experimental models showing the molecular effects of selected spices and spice-derived nutraceuticals such as cardamonin, curcumin, capsaicin, gingerol, thymoquinone, and piperine on these inflammatory pathways and the potential role of nutraceuticals in preventing chronic diseases.
The potential relationship between red meat consumption and colorectal cancer (CRC) has been the subject of scientific debate. Given the high degree of resulting uncertainty, our objective was to update the state of the science by conducting a systematic quantitative assessment of the epidemiologic literature. Specifically, we updated and expanded our previous meta-analysis by integrating data from new prospective cohort studies and conducting a broader evaluation of the relative risk estimates by specific intake categories. Data from 27 independent prospective cohort studies were meta-analyzed using random-effects models, and sources of potential heterogeneity were examined through subgroup and sensitivity analyses. In addition, a comprehensive evaluation of potential dose-response patterns was conducted. In the meta-analysis of all cohorts, a weakly elevated summary relative risk was observed (1.11, 95% CI: 1.03–1.19); however, statistically significant heterogeneity was present. In general, summary associations were attenuated (closer to the null and less heterogeneous) in models that isolated fresh red meat (from processed meat), adjusted for more relevant factors, analyzed women only, and were conducted in countries outside of the United States. Furthermore, no clear patterns of dose-response were apparent. In conclusion, the state of the epidemiologic science on red meat consumption and CRC is best described in terms of weak associations, heterogeneity, an inability to disentangle effects from other dietary and lifestyle factors, lack of a clear dose-response effect, and weakening evidence over time.
Key Teaching Points:
•The role of red meat consumption in colorectal cancer risk has been widely contested among the scientific community.•In the current meta-analysis of red meat intake and colorectal cancer, we comprehensively examined associations by creating numerous sub-group stratifications, conducting extensive sensitivity analyses, and evaluating dose-response using several different methods.•Overall, all summary associations were weak in magnitude with no clear dose-response patterns.•Interpretation of findings from epidemiologic studies investigating diet and health outcomes involves numerous methodological considerations, such as accurately measuring food intake, dietary pattern differences across populations, food definitions, outcome classifications, bias and confounding, multicollinearity, biological mechanisms, genetic variation in metabolizing enzymes, and differences in analytical metrics and statistical testing parameters.
Diet has an important role in the development of colorectal cancer. In the past few decades, findings from extensive epidemiologic and experimental investigation have linked consumption of several foods and nutrients to the risk of colorectal neoplasia. Calcium, fiber, milk, and whole grain have been associated with a lower risk of colorectal cancer, and red meat and processed meat with an increased risk. There is substantial evidence for the potential chemopreventive effects of vitamin D, folate, fruits and vegetables. Nutrients and foods may also interact, as a dietary pattern, to influence colorectal cancer risk. Diet likely influences colorectal carcinogenesis through several interacting mechanisms. These include the direct effects on immune responsiveness and inflammation, and the indirect effects of over-nutrition and obesity-risk factors for colorectal cancer. Emerging evidence also implicates the gut microbiota as an important effector in the relationship between diet and cancer. Dietary modification therefore has the promise of reducing colorectal cancer incidence.
Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.
Background:
Diets that include fruits and vegetables have been suggested as one way to reduce the risk of developing colorectal cancer (CRC); however, the association between consuming fruits and vegetables and CRC risk is not clear. The objective of the present study is to compare fruit and vegetable intake between 2 groups of Jordanians and further investigate this possible relationship.
Methods:
A history of fruit and vegetable consumption was obtained from 220 people with CRC and 281 healthy controls, all of whom were from Jordan. Both groups were matched for age, sex, occupation, and marital status. Fruit and vegetable consumption was quantified for the previous 12 months in both groups.
Results:
Total vegetable intake was associated with the risk of developing CRC. Consuming 5 servings of vegetables a day decreased the risk of developing CRC when compared with no more than 1 serving a day (odds ratio [OR] = 0.23; 95% confidence interval [CI]: 0.55-0.97). A significant direct relationship between CRC risk and consuming cauliflower and cabbage was found; however, no association was found for raw or cooked leafy vegetable and other vegetable types. Consuming several types of fruits also revealed no association with risk of CRC, although an increased intake of dates and figs was associated with a reduced risk of developing CRC. The ORs for the highest intake of servings compared with the lowest intake were 0.48 (95% CI: 0.27-0.87; P = .004) for dates and 0.604 (95% CI: 0.35-1.06; P = .003) for figs.
Conclusions:
Consuming fruits and vegetables did not significantly correlate with a lowered incidence of CRC. However, a trend of protection was detected for several types of fruits and vegetables.
Background and Aims: Diets including fruits and vegetables have been suggested as one way to reduce the risk of developing cancer. More specifically, some researchers have argued that fruits and vegetables in the diet show an inverse association with the risk of developing colorectal cancer (CRC). The association between the consumption of fruits and vegetables and the risk of CRC is not clear. The objective of the present study is to compare the intake of fruits and vegetables in two groups of Jordanians subjects and to further investigate the possible relationship between the consumption of fruits and vegetables and the risk of developing CRC. Methods: A history of the consumption of fruits and vegetables was obtained from 220 subjects diagnosed with CRC, and 281 healthy disease free control subjects. Both groups were matched for age, gender, occupation and marital status. Fruits and vegetables consumption was quantified for the previous 12 months in both groups. Results: Intakes of total vegetables was found to be associated with the risk of developing CRC. Consumption of five servings of vegetables/day decreased the risk of developing CRC when compared with 1 or fewer servings/day (OR=0.23; 95%CI: 0.55-0.97). A significant direct relationship between CRC risk and consumption of cauliflower and cabbage was found. No association was found for raw or cooked leafy vegetable and other vegetable types, with the risk of CRC development. The consumption of several types of fruits (apples, pears, banana, peach, grapes, melon, watermelon, strawberry, citrus fruits, apricots, alovera, and including dried fruits) showed no association with CRC risk. The increased intake of dates and figs was found to be associated with reduced risk of CRC development. The odd ratio for the highest intake of servings compared with lower intake was 0.48 (95%CI: 0.27-0.87; p = 0.004) for dates and 0.604 (95%CI: 0.0.35-1.06 p = 0.003) for figs.
Conclusion: Fruits and vegetables consumption was not significantly associated with lowering the incidence of CRC. However, a trend of protection was detected for several types of consumed fruits and vegetables.
Poultry intake has been inconsistently associated with incidence or mortality of colorectal cancer (CRC) in epidemiologic studies. The purpose of this study was to assess their relationships by performing a dose-response meta-analysis.
We conducted a search of PubMed database between January 1966 and July 2013 for prospective studies that reported relative risks (RRs) with 95 % confidence interval (CIs) of CRC for at least three categories of poultry intake. Dose-response relationships were examined with the generalized least-squares trend estimation. Study-specific results were pooled with a random-effects model. Subgroup, sensitivity, and meta-regression analyses were also conducted to explore heterogeneity.
Sixteen studies on poultry intake and CRC incidence, and four studies regarding poultry intake and CRC mortality were identified. These studies involved a total of 13,949 incident CRC cases and 983 CRC deaths. The RRs of CRC for higher compared with lower intake of poultry were reported in these studies, and the reported levels of poultry intake varied substantially. Results of the dose-response meta-analysis conferred a RR of 0.89 (95 % CI 0.81-0.97) for an increase in poultry intake of 50 g/day. The results were not sensitive to any individual studies and were similar for colon and rectal cancer. Poultry intake was not associated with CRC mortality (RR for 50 g/day = 0.97, 95 % CI 0.79-1.20).
This meta-analysis indicates that poultry intake may be moderately associated with reduced incidence of CRC.
The observed associations of fruit and vegetable consumption with the risk of colorectal cancer have been inconsistent. Therefore, we aimed to evaluate the association of fruit and vegetable consumption with the risk of colorectal cancer among Chinese men.
61,274 male participants aged 40-74 years were included. A validated food frequency questionnaire was administered to collect information on usual dietary intake, including 8 fruits and 38 vegetables commonly consumed by residents of Shanghai. Follow-up for diagnoses of colon or rectal cancer was available through 31 December 2010. Dietary intakes were analyzed both as categorical and continuous variables. Multivariable-adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) were calculated for colorectal, colon, and rectal cancers using Cox proportional hazards models.
After 390,688 person-years of follow-up, 398 cases of colorectal cancer (236 colon and 162 rectal) were observed in the cohort. Fruit consumption was inversely associated with the risk of colorectal cancer (fifth vs. first quintile HR 0.67; 95 % CI 0.48, 0.95; p trend = 0.03), whereas vegetable intake was not significantly associated with risk. The associations for subgroups of fruits and legumes, but not other vegetable categories, were generally inversely associated with the risk of colon and rectal cancers.
Fruit intake was generally inversely associated with the risk of colorectal cancer, whereas vegetable consumption was largely unrelated to risk among middle-aged and older Chinese men.
China, Mongolia, Korea and Japan constitute North-East Asia. For reasons of largely shared ethnicity and culture, with various degress of mixed Chinese and Altaic elements, as well as geographical contiguity, they can be usefully grouped together for studies of chronic disease prevalence and particularly cancer. The fact of problems shared in common, with increasing disease rates, underlines the necessity for a coordinated approach to research and development of control measures. To provide a knowledge base, the present review of cancer registration and epidemiology data was conducted. The most frequent cancers in males of North-East Asia are in the lung, liver and stomach, with considerable geographical and temporal variation in their respective prevalences. However, colorectal cancer is also of increasing importance. In females the breast, together with the lung in China, the liver in Mongolia and the stomach in Korea and Japan, are most frequent. Variation in risk factors depends to a large extent on the local level of economic development but overall the countries of the region face similar challenges in achieving effective cancer control.
High intake of red meat has been associated with increased risk of colorectal cancer in Western countries. There has been much interest in the role of n-3 polyunsaturated fatty acids (PUFA) in colorectal cancer prevention, but epidemiological findings are limited and inconsistent. The objective of our study was to examine associations of meat, fish and fat intake with risk of colorectal cancer, paying particular attention to the subsite within the colorectum. Data were from the Fukuoka Colorectal Cancer Study, a population-based case-control study, covering 782 cases and 793 controls. Diet was assessed by interview, using newly developed personal-computer software for registering semiquantitative food frequencies. The intake of beef/pork, processed meat, total fat, saturated fat or n-6 PUFA showed no clear association with the overall or subsite-specific risk of colorectal cancer. There was an almost significant inverse association between n-3 PUFA and the risk of colorectal cancer; the covariate-adjusted odds ratio for the highest (median 3.94 g/day) versus lowest (median 1.99 g/day) quintile of energy-adjusted intake was 0.74 (95% confidence interval 0.52-1.06, trend P=0.050). The consumption of fish and fish products was similarly inversely related to the risk although the association was not statistically significant. These associations were more evident for distal colon cancer; adjusted odds ratio for the highest versus lowest quintile of n-3 PUFA intake was 0.56 (95% confidence interval 0.34-0.92, trend P=0.02). Our findings do not support the hypothesis that consumption of red meat increases colorectal cancer risk but do suggest that high intake of fish may decrease the risk, particularly of distal colon cancer.
The relationship between red meat consumption and colorectal cancer (CRC) has been the subject of scientific debate. To estimate the summary association between red meat intake and CRC and to examine sources of heterogeneity, a meta-analysis of prospective studies was conducted. Thirty-four prospective studies of red meat and CRC were identified, of which 25 represented independent nonoverlapping study populations. Summary relative risk estimates (SRREs) for high versus low intake and dose-response relationships were calculated. In the high versus low intake meta-analysis, the SRRE was 1.12 (95% CI: 1.04-1.21) with significant heterogeneity (P=0.014). Summary associations were modified by tumor site and sex. The SRREs for colon cancer and rectal cancer were 1.11 (95% CI: 1.03-1.19) and 1.19 (95% CI: 0.97-1.46), respectively. The SRREs among men and women were 1.21 (95% CI: 1.04-1.42) and 1.01 (95% CI: 0.87-1.17), respectively. The available epidemiologic data are not sufficient to support an independent and unequivocal positive association between red meat intake and CRC. This conclusion is based on summary associations that are weak in magnitude, heterogeneity across studies, inconsistent patterns of associations across the subgroup analyses, and the likely influence of confounding by other dietary and lifestyle factors.
In a 6-year prospective study, the authors examined the relation between diet and incident colon cancer among 32,051 non-Hispanic white cohort members of the Adventist Health Study (California, 1976-1982) who, at baseline, had no documented or reported history of cancer. The risk of colon cancer was determined from proportional hazards regression with adjustment for age and other covariates. The authors found a positive association with total meat intake (risk ratio (RR) for > or =1 time/week vs. no meat intake = 1.85, 95% confidence interval (CI) 1.19-2.87; p for trend = 0.01) and, among subjects who favored specific types of meat, positive associations with red meat intake (RR for > or =1 time/week vs. no red meat intake = 1.90, 95% CI 1.16-3.11; p for trend = 0.02) and white meat intake (RR for > or =1 time/week vs. no white meat intake = 3.29, 95% CI 1.60-6.75; p for trend = 0.006). An inverse association with legume intake (RR for >2 times/week vs. <1 time/week = 0.53, 95% CI 0.33-0.86; p for trend = 0.03) was observed. Among men, a positive association with body mass index was observed (relative to the RR for tertile III (>25.6 kg/m2) vs. tertile I (<22.5 kg/m2) = 2.63, 95% CI 1.12-6.13; p for trend = 0.05). A complex relation was identified whereby subjects exhibiting a high red meat intake, a low legume intake, and a high body mass experienced a more than threefold elevation in risk relative to all other patterns based on these variables. This pattern of putative risk factors would likely contribute to increases in both insulin resistance (high body mass, high red meat intake) and glycemic load (low legume intake), a synergism that, if causal, implicates hyperinsulinemic exposure in colon carcinogenesis. The overall findings from this cohort identify both red meat intake and white meat intake as important dietary risk factors for colon cancer and raise the possibility that the risk due to red meat intake reflects a more complex etiology.
The role of personality in the causation of cancer has been controversial. We examined this question in a large, prospective study.
From June through August 1990, 30 277 residents of Miyagi Prefecture in northern Japan completed a Japanese version of the short form of the Eysenck Personality Questionnaire-Revised and a questionnaire on various health habits. There were 671 prevalent cases of cancer at baseline, and 986 incident cases of cancer were identified during 7 years of follow-up, through December 1997. We used Cox proportional hazards regression to estimate the relative risk (RR) of incident cancer (total, stomach, colorectal, breast, and lung) according to four levels of each of four personality subscales (extraversion, neuroticism, psychoticism, and lie), with adjustment for sex, age, education, smoking, alcohol use, body mass index, and family history of cancer. Statistical tests were two-sided.
Multivariable RRs of total cancer for individuals in the highest level of each personality subscale as compared with those in the lowest were 0.9 for extraversion (95% confidence interval [CI] = 0.7 to 1.1; P(trend) =.32), 1.1 for psychoticism (95% CI = 0.9 to 1.3; P(trend) =.96), 0.9 for lie (95% CI = 0.7 to 1.0; P(trend) =.19), and 1.2 for neuroticism (95% CI = 1.0 to 1.4; P(trend) =.06). There were no associations between any personality subscale and risk of specific cancers. Neuroticism showed statistically significant positive, linear associations with prevalent cancer at baseline (P(trend)<.001) and with the 320 incident cancer cases diagnosed within the first 3 years of follow-up (P(trend) =.03); however, it showed no association with the 666 cases diagnosed during the fourth through the seventh years of follow-up (P(trend) =.43).
Our data do not support the hypothesis that personality is a risk factor for cancer incidence. The association between neuroticism and prevalent cancer may be a consequence, rather than a cause, of cancer diagnosis or symptoms.
In Denmark, the intake of dietary iron has decreased since 1987, when the mandatory iron fortification of flour (30 mg carbonyl iron/kg) was stopped. Since there have been no studies of iron status in elderly Danes after the abolishment of iron fortification, there is a need to assess actual iron status in the elderly population. The objective was to evaluate iron status and the relationship with food composition and dietary and supplemental iron intake in an elderly population in Copenhagen County. Participants in this health examination survey were 358 subjects (171 men, 187 women) 80 years of age from a 1914 cohort study. Blood samples included serum ferritin and hemoglobin (Hb). A dietary survey was performed in 232 subjects (120 men, 112 women) using a dietary history method. Median serum ferritin was 100 microg/l in men and 78 microg/l in women ( p<0.001). Ferritin concentrations <16 microg/l (i.e., depleted iron stores) were found in three men (2%) and in ten women (5%). Median Hb was 140 g/l in men and 131 g/l in women ( p<0.001). Three subjects (0.84%) had iron deficiency anemia (i.e., ferritin <13 microg/l and Hb <5th percentile for iron-replete subjects (121 g/l in men, 114 g/l in women). Ferritin concentrations >300 microg/l (i.e., iron overload) were found in 15 (9%) men and in 5 (3%) women. Median dietary iron intake was higher in men (8.7 mg/day) than in women (7.3 mg/day) ( p<0.001). Serum ferritin was positively correlated to dietary intake of iron, meat, and alcohol and to body mass index in men. Serum ferritin displayed a negative correlation to the consumption of tea. The use of vitamin-mineral supplements containing iron had no influence on iron status. Dietary intake of iron and/or the bioavailability of dietary iron were adequate to maintain a favorable iron status in 80-year-old subjects displaying a low prevalence of iron deficiency and a moderate prevalence of iron overload.
The aim of the study was to assess the frequency of the C282Y and H63D mutations of the hemochromatosis gene (HFE) in ethnic Danes. The series comprised 2501 subjects (1284 men) of Danish heritage who were drawn at random from the Census Registry in age cohorts of 30, 40, 50, and 60 years. The frequency of the C282Y and H63D mutations was assessed on blood samples by genotyping using a polymerase chain reaction (PCR) technique. The HFE genotype distribution was in Hardy-Weinberg equilibrium (p=0.85). C282Y mutation: 9 subjects (0.36%) were homozygous and 265 subjects (10.6%) were heterozygous. H63D mutation: 40 subjects (1.6%) were homozygous and 584 subjects (23.4%) were heterozygous. C282Y/H63D compound heterozygosity was found in 36 subjects (1.4%). The C282Y allele frequency was 5.7% [95% confidence interval (CI) 5.0-6.3%] and the H63D allele frequency was 13.3% (95% CI 12.3-14.2%). In conclusion, the C282Y frequency is relatively high in the Danes, being close to the frequency in other Scandinavian countries, i.e., Iceland 5.1%, the Faroe Islands 6.6%, and Sweden 5.7%, but significantly lower than in Norway 6.6% (p=0.02). Also, the H63D frequency in Danes is close to and not significantly different from the frequency in Iceland 10.9%, Norway 11.2%, and Sweden 12.4%, but significantly lower than in the Faroe Islands 15.4% (p=0.046).
There were few prospective cohort studies in Japan using cancer incidence as an endpoint.
We conducted a baseline survey with two self-administered questionnaires regarding lifestyle and personality on the residents aged 40 to 64 years in 14 municipalities of Miyagi Prefecture, Japan, during June through August, 1990. Out of the eligible 51,921 residents, 47,605 (91.7%) responded to the lifestyle questionnaire and formed the cohort under study. We collated the list of subjects in the cohort with the Miyagi Prefectural Cancer Registry data through December 31, 1997. To identify the same person between two data, we used four personal characteristics (sex, name, birthday, and municipality of dwelling).
We ascertained 1,718 cases of incident cancer. In men, gastric cancer was the leading site of cancer (27.7%), followed by lung cancer and colon cancer. In women, breast cancer was the most common (19.6%), followed by gastric cancer and colon cancer.
By record linkage with regional cancer registry data, it becomes possible for us to investigate the effect of various life-styles on cancer incidence in the Miyagi Cohort Study. We expect this data to contribute to the progress of research on cancer etiology and cancer prevention.
Consumption of red and processed meat has been associated with colorectal cancer in many but not all epidemiological studies; few studies have examined risk in relation to long-term meat intake or the association of meat with rectal cancer.
To examine the relationship between recent and long-term meat consumption and the risk of incident colon and rectal cancer.
A cohort of 148 610 adults aged 50 to 74 years (median, 63 years), residing in 21 states with population-based cancer registries, who provided information on meat consumption in 1982 and again in 1992/1993 when enrolled in the Cancer Prevention Study II (CPS II) Nutrition Cohort. Follow-up from time of enrollment in 1992/1993 through August 31, 2001, identified 1667 incident colorectal cancers. Participants contributed person-years at risk until death or a diagnosis of colon or rectal cancer.
Incidence rate ratio (RR) of colon and rectal cancer.
High intake of red and processed meat reported in 1992/1993 was associated with higher risk of colon cancer after adjusting for age and energy intake but not after further adjustment for body mass index, cigarette smoking, and other covariates. When long-term consumption was considered, persons in the highest tertile of consumption in both 1982 and 1992/1993 had higher risk of distal colon cancer associated with processed meat (RR, 1.50; 95% confidence interval [CI], 1.04-2.17), and ratio of red meat to poultry and fish (RR, 1.53; 95% CI, 1.08-2.18) relative to those persons in the lowest tertile at both time points. Long-term consumption of poultry and fish was inversely associated with risk of both proximal and distal colon cancer. High consumption of red meat reported in 1992/1993 was associated with higher risk of rectal cancer (RR, 1.71; 95% CI, 1.15-2.52; P = .007 for trend), as was high consumption reported in both 1982 and 1992/1993 (RR, 1.43; 95% CI, 1.00-2.05).
Our results demonstrate the potential value of examining long-term meat consumption in assessing cancer risk and strengthen the evidence that prolonged high consumption of red and processed meat may increase the risk of cancer in the distal portion of the large intestine.
Adequate fruit and vegetable intake has been suggested to protect against colorectal cancer. However, several recent prospective studies have reported no association. We therefore examined the association between fruit and vegetable intakes and the risk of colorectal cancer in a prospective cohort study in Japan.
Between June and August 1990, 47 605 Japanese men and women completed a self-administered questionnaire, including a food-frequency questionnaire. We divided the subjects into quartiles based on their self-reported fruit and vegetable consumption. There were 165 colon cancer and 110 rectal cancer incidences identified during 7 years of follow-up, to the end of December 1997. We used Cox proportional hazards models to estimate the relative risk (RR) of developing colorectal cancer according to the level of fruit and vegetable consumption, applying adjustments for potential confounders.
No statistically significant association was observed between fruit and vegetable consumption and the risk of colorectal cancer. The multivariate RR of colon cancer in the highest quartile of fruit and vegetable intake compared with the lowest was 1.13 (95% confidence interval (CI) 0.73-1.75), the RR for vegetables alone was 1.24 (95% CI 0.79-1.95) and that for fruit alone was 1.45 (95% CI 0.85-2.47). The corresponding multivariate RRs for rectal cancer were 1.12 (95% CI 0.67-1.89), 1.14 (95% CI 0.67-1.93) and 1.41 (95% CI 0.73-2.73).
We found no association between the consumption of fruit and vegetables and the risk of colorectal cancer among the Japanese population.
Associations between intake of specific nutrients and disease cannot be considered primary effects of diet if they are simply the result of differences between cases and noncases in body size, physical activity, and metabolic efficiency. Epidemiologic studies of diet and disease should therefore be directed at the effect of nutrient intakes independent of total caloric intake in most instances. This is not accomplished with nutrient density measures of dietary intake but can be achieved by employing nutrient intakes adjusted for caloric intake by regression analysis. While pitfalls in the manipulation and interpretation of energy intake data in epidemiologic studies have been emphasized, these considerations also highlight the usefulness of obtaining a measurement of total caloric intake. For instance, if a questionnaire obtained information on only cholesterol intake in a study of coronary heart disease, it is possible that no association with disease would be found even if a real positive effect of a high cholesterol diet existed, since the caloric intake of cases is likely to be less than that of noncases. Such a finding could be appropriately interpreted if an estimate of total caloric intake were available. The relationships between dietary factors and disease are complex. Even with carefully collected measures of intake, consideration of the biologic implications of various analytic approaches is needed to avoid misleading conclusions.
The association of diet, smoking/drinking and occupation with subsequent risk of fatal colorectal cancer was investigated in a cohort of 17,633 white males aged 35 and older, who completed a mail questionnaire in 1966. During the subsequent 20 years of follow-up, 120 colon cancer and 25 rectal cancer deaths were identified. Due to small numbers, no significant dose-response trends were observed in the study, but risk of colon cancer was elevated among heavy cigarette smokers (greater than or equal to 30/day; RR = 2.3, 95% CI 0.9-5.7), heavy beer drinkers (greater than or equal to 14 times/month; RR = 1.9, 95% CI 1.0-3.8) and white-collar workers (RR = 1.7, 95% CI 1.0-3.0) or crafts workers within service and trade industries (RR = 2.6, 95% CI 1.1-5.8). In addition, an increased risk was seen for those who consumed red meat more than twice a day (RR = 1.8, 95% CI 0.8-4.4). Risk patterns for cancers of the colon and rectum combined were similar to those reported for cancer of the colon, but the estimates were somewhat dampened. Our findings support previous reports that a high intake of red meat and a sedentary life-style may increase the risk of colon cancer. Int. J. Cancer 77:549-553, 1998. (C) 1998 Wiley-Liss, Inc.dagger
To assess the relation of lifestyle factors, personality and some biologic markers to cancer incidence, and to evaluate the effectiveness of cancer screening, a cohort study was conducted among all residents aged 40 to 64 years in 14 municipalities of Miyagi Prefecture, Japan. The baseline survey consisted of self-completed questionnaires concerning lifestyle and personality (Eysenck Personality Questionnaire-Revised), and serum samples collected from a part of the subjects. The proportion of the subjects who appropriately responded to the lifestyle questionnaire (response rate) was 91.7% (47, 605 persons of the total 51, 921 residents), indicating that representative data could be obtained. Of these, 41, 442 persons (87.1%) also completed a personality questionnaire, and serum samples were collected from 8, 896 persons (18.7%). Linkage of these baseline data with the cancer incidence data of a population-based cancer registry, and with the records of cancer screening at a cancer detection center will provide useful information for comprehensive cancer prevention. J Epidemiol. 1995; 5 : 153-157.
The authors investigated the association of intakes of meat and fat with colorectal cancer in a prospective cohort of women in the United States. Between 1987 and 1989, 45,496 women completed a 62-item National Cancer Institute/Block food frequency questionnaire, and during 386,716 person-years of follow-up, there were 487 incident cases of colorectal cancer. The authors used Cox proportional hazards regression to estimate relative risks and 95% confidence intervals for total meat, red meat, white meat, processed meat, and well-done meat intakes, as well as for total fat, saturated fat, and unsaturated fat. Relative risks for increasing quintiles of total meat and red meat consumption indicated no association with colorectal cancer (relative risk for high compared with low quintile = 1.10, 95% confidence interval: 0.83, 1.45) for red meat. For total fat, there was also no association with increasing quintiles of consumption (relative risk for high compared with low quintile = 1.14, 95% confidence interval: 0.86, 1.53). Additionally, none of the other subtypes of either meat or fat showed any association with colorectal cancer. This study provided no evidence of an association between either meat or fat (or any of their subtypes) and colorectal cancer incidence, but the authors cannot rule out the possibility of a modest association.
A high level of available tissue iron may increase the risk of cancer through its contribution to the production of free oxygen radicals. Serum iron, total iron-binding capacity (TIBC) and transfer-fin saturation levels were studied for their prediction of different cancers in a cohort of 41,276 men and women aged 20–74 years and initially free from cancer. During a mean follow-up of 14 years, 2,469 primary cancer cases were diagnosed. Excess risks of colorectal and lung cancers were found in subjects with transferrin saturation level exceeding 60%. The relative risks, adjusted for age, sex and smoking, were 3.04 for colorectal cancer and 1.51 for lung cancer, in comparison with subjects having lower levels. The risk of lung cancer was inversely related to serum TIBC, with a relative risk between the highest and lowest quartiles of 0.69 for men and 0.19 for women. For the risk of stomach cancer, we detected inverse relationships with serum iron and with transferring saturation and a positive relationship with TIBC, but these associations weakened when the cancer cases occurring during the 5 first years of follow-up were excluded. High iron stores may increase th risk of colorectal cancer, whereas low iron stores may be an early sign of occult stomach cancer.
Objectives: Based on previous epidemiological studies, high fat and meat consumption may increase and fiber, calcium, and vegetable consumption may decrease the risk of colorectal cancer. We sought to address these hypotheses in a male Finnish cohort.
Methods: We analyzed data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study) where 27, 111 male smokers completed a validated dietary questionnaire at baseline. After an average of 8 years of follow-up, we documented 185 cases of colorectal cancer. The analyses were carried out using the Cox proportional hazards model.
Results: The relative risk (RR) for men in the highest quartile of calcium intake compared with men in the lowest quartile was 0.6 (95% CI 0.4–0.9, p for trend 0.04). Likewise, the intake of milk protein and the consumption of milk products was inversely associated with risk of colorectal cancer. However, intake of dietary fiber was not associated with risk, nor was fat intake. Consumption of meat or different types of meat, and fried meat, fruits or vegetables were not associated with risk.
Conclusions: In this cohort of men consuming a diet high in fat, meat, and fiber and low in vegetables, high calcium intake was associated with lowered risk of colorectal cancer.
Objective: The purpose was to investigate whether dietary associations with risk of colon cancer in women differ by family history of the disease.
Methods: Data were analyzed from a prospective cohort study of 35,216 Iowa (United States) women aged 55 to 69 years at baseline. Through 31 December 1995, 241 colon cancers were identified through record linkage with the State Health Registry. The cohort was stratified on family history of colon cancer in first-degree relatives; nutrient intakes were divided into tertiles.
Results: Analyses using Cox regression revealed that the association of most dietary components with colon cancer incidence were similar for individuals with and without a family history. However, total calcium intake was associated inversely with colon cancer among women with a negative family history (relative risk [RR]=0.50 for upper cf lower tertile, P < 0.001), but was unrelated to incidence for women with a positive family history (RR=1.1 for upper cf lower tertile, P=0.69). Similarly, total vitamin E intake was associated with lower risk among women with a negative family history (RR=0.67 for upper cf lower tertile, P=0.04), but not among women with a positive family history (RR=0.87 for upper cf lower tertile, P=0.67). High intakes of fiber, fruits, and vegetables were each weakly inversely associated with risk among family-history negative women, but not among family-history positive women.
Conclusions: These data, if corroborated, suggest that dietary factors typically associated with lower risk may be less effective risk-reduction interventions against colon cancer for individuals with a family history of colon cancer.
Because of the potential significance of secondary bile acids and cholesterol metabolites formed by the intestinal microflora in the pathogenesis of colon cancer, fecal microbial 7alpha-dehydroxylase and cholesterol dehydrogenase activities were assayed in colorectal cancer patients, patients with adenomatous polyps, asymptomatic controls, and normal controls. The mean 7alpha-dehydroxylase activity per 100 mg of dry feces per 2 hr incubation for colorectal cancer patients was significantly greater than either asymptomatic controls or normal controls. Patients with polyps had greater activity than controls, but did not differ significantly from the cancer patients or asymptomatic controls. The mean cholesterol dehydrogenase activity for colorectal cancer patients was significantly greater than controls. Patients with polyps also had greater activity than controls. No differences in the level of fecal beta-glucuronidase activity were found among the four risk groups. These data support the concept that patients with colorectal cancer are more able to convert primary bile acids and cholesterol to microbial products in colon contents than are controls. Such differences in the activity of intestinal microflora may serve as biochemical indicators that will reflect the enzymic activity of the fecal flora as well as the key intraluminal compounds in identifying populations at different risk for developing colorectal cancer.
Intestinal exposure to ingested iron may be a principal determinant of human colorectal cancer risk. Evidence exists associating iron with both the initiating and promoting phases of carcinogenesis as well as somatic defenses against early cancers through hypoferremia (progression or proliferation). Iron intake and the ingestion of associated foods that greatly affect iron bioavailability and absorption (phytate, tannin, ascorbate, and alcohol) vary widely between high-risk and low-risk countries as well as within the United States. These variances in intake may explain not only the gradients in risk between populations, but the crossover in risk between sexes related to age within the United States. Human and rodent studies support the above hypothesis and are reviewed herein, however they are few in number and in many cases lack key data.
Associations between intake of specific nutrients and disease cannot be considered primary effects of diet if they are simply the result of differences between cases and noncases in body size, physical activity, and metabolic efficiency. Epidemiologic studies of diet and disease should therefore be directed at the effect of nutrient intakes independent of total caloric intake in most instances. This is not accomplished with nutrient density measures of dietary intake but can be achieved by employing nutrient intakes adjusted for caloric intake by regression analysis. While pitfalls in the manipulation and interpretation of energy intake data in epidemiologic studies have been emphasized, these considerations also highlight the usefulness of obtaining a measurement of total caloric intake. For instance, if a questionnaire obtained information on only cholesterol intake in a study of coronary heart disease, it is possible that no association with disease would be found even if a real positive effect of a high cholesterol diet existed, since the caloric intake of cases is likely to be less than that of noncases. Such a finding could be appropriately interpreted if an estimate of total caloric intake were available. The relationships between dietary factors and disease are complex. Even with carefully collected measures of intake, consideration of the biologic implications of various analytic approaches is needed to avoid misleading conclusions.
A simultaneous case-control study on stomach cancer and colo-rectal cancer involving 93 cases with stomach cancer, 93 cases with colo-rectal cancer and 186 controls was conducted using a common questionnaire at the Aichi Cancer Center Hospital in 1981-83. A fondness for salty tastes, especially salted foods such as pickled hakusai (vegetable) and dried & salted fishes, which are typical traditional Japanese foods showed a significantly positive association with stomach cancer (relative risk(RR) = 2.60, P less than 0.01). On the other hand, the habit of eating a western-style breakfast, particularly for 10 years or more made a significant contribution to the risk of colon cancer (RR = 2.24, P less than 0.05) but conversely decreased the risk of stomach cancer (RR = 0.50, not significant (NS)) and rectal cancer (RR = 0.40, NS). In this study, relatively frequent intakes (4 times/week) of some vegetables, i.e. pumpkin, green pepper, onion and cabbage, showed high relative risks for both stomach and colon cancers, contrary to the findings of previous epidemiological studies. Cigarette smoking increased the risk of stomach cancer (RR = 1.99, NS) but decreased that of colon cancer (RR = 0.61, NS). There was no positive relation between drinking and cancer at any site. Some other factors with opposite effects on the two contrasting cancers and some independent factors were identified in this comparative case-control study.
The effect of 2 bile acids in colon carcinogenesis was studied in rats. A single dose of N methyl N' nitro N nitrosoguanidine (MNNG) was instilled intrarectally. Subsequently, repeated intrarectal doses of lithocholic or taurodeoxycholic acid were administered. Both bile acids increased the frequency of MNNG induced colorectal neoplasms. Neither bile acid induced tumors when used alone. The lesions were like those induced by MNNG alone, and included adenomas and adenocarcinomas. The bile acids acted as promotors of carcinogenesis.
The effect of a high-fat, high-beef diet and of method of preparation of beef in the diet on the fecal bile acids and neutral sterols and on the activities of fecal bacterial beta-glucuronidase, cholesterol dehydrogenase and 7 alpha-dehydroxylase was studied in healthy men and women, 24-41 years old, who were consuming a customary mixed-western diet. The experimental diets were high in fat and beef, which was cooked rare, medium or well-done. The sequence of dietary regimen was selected at random and each diet phase lasted for 4 weeks. Individual 24-hour fecal specimens were collected from each volunteer for the final 3 days during each dietary period, including pre- and post-experimental periods while they were consuming a customary mixed-western diet. The mode of cooking beef in the high-fat, high-beef experimental diets had no influence on the fat and protein content of the diets but the fat content of experimental diets was high compared to customary mixed-western diet. Fecal bacterial beta-glucuronidase activity and fecal secondary bile acid and cholesterol metabolite levels were significantly higher during the experimental diet periods but the fecal bacterial activities of 7 alpha-dehydroxylase and cholesterol dehydrogenase were unaffected. The mode of cooking beef in experimental diets had no influence on the fecal bacterial enzymes and on the excretion of fecal bile acids and cholesterol metabolites.
To investigate the subsite-specific risk factors for colorectal cancer, we conducted a case-control study, using a common questionnaire which inquired about general lifestyles over the past five years (1988-92), at the Aichi Cancer Center Hospital, Nagoya, Japan. This study compared 432 patients with histopathologically diagnosed colorectal cancer (94 proximal colon [cecum, ascending colon, transverse colon]; 137 distal colon [descending colon, sigmoid colon]; 201 rectum [rectosigmoid, rectum]); and 31,782 first-visit outpatient controls who were free from cancer. In both genders, habitual smoking selectively increased the risk for rectum cancer. Soft or loose feces increased the risk for all subsites of colorectal cancer, particularly in female rectum cancer (odds ratio [OR] = 4.5). Among female dietary habits, Japanese-style foods decreased the risk for distal colon cancer, but increased the risk for proximal colon cancer. These results suggested that the risk factors for colorectal cancer differ by subsite among such a low-risk population as the Japanese. It is suggested also that 'irritable bowel' (soft or loose feces) might be associated with distal subsites of colorectal cancer, independently or combined with habitual smoking.
The relation of dietary factors to the risk of adenomas of the sigmoid colon was examined in men receiving a retirement health examination at the Self-Defense Forces Fukuoka Hospital between October 1986 and 1990. A total of 187 adenoma cases and 1557 controls with normal colonoscopy were identified in the series. Cases were further classified into small-adenoma (< 5 mm, n = 78) and large-adenoma (> or = 5 mm, n = 67) groups. The consumptions of selected foods and beverages were ascertained before colonoscopy by means of a self-administered questionnaire. After adjustment for smoking, alcohol use, rank and body mass index, low rice consumption and high meat intake were independently associated with an increased risk of large adenomas. The risk of small adenomas was not related to either rice consumption or meat intake. Adjusted odds ratios of large adenomas for the low, intermediate and high consumption levels of rice were estimated to be 1.0 (referent), 0.83 and 0.43, respectively (trend P = 0.08), and the corresponding figures for meat consumption were 1.0 (referent), 1.58 and 2.38, respectively (trend P = 0.02). The findings suggest that low rice consumption and high meat intake may promote the growth of colon adenomas, thereby increasing the risk of colon cancer.
High red meat diets have been linked with risk of sporadic colorectal cancer; but their effects on mutations which occur in this cancer are unknown. G-->A transitions in K-ras occur in colorectal cancer and are characteristic of the effects of alkylating agents such as N-nitroso compounds (NOC). We studied th effect of red meat consumption on faecal NOC levels in eight male volunteers who consumed diets low or high in meat (60 or 600 g/day), as beef, lamb or pork, whilst living in a metabolic suite. Increased intake of red meat induced a significant (P<0.024) 3-fold increase from 40 + or - 7 to ab average of 113 + or - 25 microgram/day NOC, a range of exposure in faeces similar to that from tobacco-specific NOC in cigarette smoke. THe diets were isoenergetic and contained equal amounts of fat, but concentrations of heterocyclic amines were low. Faecal excretion of the promotor ammonia was significantly increased to 6.5 + or - 1.08 mmol/day. When the high red meat diets were supplemented with 20 g phytate-free wheat bran in six volunteers there was no reduction in NOC levels (mean 138 + or - 41 microgram/day NOC), but faecal weight increased. Higher starch and non-starch polysaccharide intakes reduced intraluminal cross-linking in microcapsules (r=-0.77) and reduced faecal pH (r=-0.64). In two volunteers there was no effect of 600 g white meat and fish o faecal NOC (mean low white meat diet 68 + or - 10 microgram/day, high white meat 56 + or -6 microgram/day nor on faecal nitrate, nitrite and iron. Faecal nitrite levels increased on changing from a white to red meat diet (mean high white meat diet 46 + or - 7 mg/day, high red meat diet mean 80 + or - 7 mg/day.) Increased endogenous production of NOC and precursors from increased red meat, but not white meat and fish, consumption may be relevant to the aetiology of colorectal cancer.
Prospectively gathered data from the National Health and Nutrition Examination Survey I and the National Health Evaluation Follow-Up Study were analyzed to evaluate the risk of colorectal cancer due to consumption of iron. Morbidity and mortality data due to colorectal cancer were available on 14,407 persons first interviewed in 1971 and followed through 1986. A total of 194 possible colorectal cancers occurred in this group over the 15-year period. Subsite analysis showed that the risk of colon cancer due to iron intake was elevated throughout the colon for both men and women, with the highest adjusted risks for the interquartile range seen in the proximal colon for females (relative risk, 1.51; 95% confidence interval, 1.41-1.60). The risk of rectal cancer was not significantly elevated for men or women. Elevated serum iron was also associated with increased risk; however, this effect was strongest in the distal (rather than proximal) colon and was significant only among females (adjusted relative risk, 1.73; 95% confidence interval, 1.03-2.92). The mean transferrin saturation was higher among cases than controls (30.7 versus 28.7%), but total iron-binding capacity did not seem to predict the occurrence of colorectal cancer. Proportional hazards models confirmed that the effects of iron and serum iron were not confounded by age, gender, energy consumption, fat intake, or other known risk factors for colorectal cancer. These data suggest that iron may confer an increased risk for colorectal cancer, and that the localization of risk may be attributable to the mode of epithelial exposure. It seems that luminal exposure to iron increases risk proximally, whereas humoral exposure increases risk distally. These differences may be due to such factors as oxidation state, binding proteins and the presence of other cofactors such as bile acids, products of bacterial metabolism.
The relationship of meat, fish, fat, fibre or calcium consumption to the risk of colon cancer was examined in a prospective study conducted by the Norwegian National Health Screening Service. Between 1977 and 1983, 50,535 Norwegian men and women aged 20-54 attended the health screening and completed a semi-quantitative questionnaire about food frequency. During a mean follow-up of 11.4 years, 143 cases of colon cancer were identified for analyses through a link with the Norwegian Cancer Registry. The relative risk of colon cancer was 3.5 (95% CI, 1.02-11.9) in women who consumed sausages as their main meal five or more times a month, compared with the risk in those who reported a consumption frequency of less than once a month. There was an increase in the relative risk with increasing frequency of consumption (P for linear trends = 0.03). Among men, the association was not statistically significant, but the trend was in the same direction as that of the women. The frequency of consuming meat meals in general, including meat stews, roasted meat, meat balls, fish or milk, was not associated with a risk of colon cancer. No trends in relative risks of colon cancer were found to be associated with intake of total energy intake or with energy-adjusted intake of total fat, saturated fat, monounsaturated fat, dietary fibre or calcium. In conclusions, this prospective study provided no evidence of association between intake of meat, fish, fat, energy, fibre or calcium and risk of colon cancer, although an increased risk with frequent consumption of sausages was suggested.
The relation between diet and female colorectal cancer was analyzed in a prospective study of 14,727 women aged 34-65 years, who were enrolled at mammographic screening clinics in New York and Florida from 1985 to 1991. They were followed through the end of 1994 (average 7.1 yrs) by a combination of direct contact through mail and telephone and record linkages with regional tumor registries, resulting in 100 incident cases of colorectal cancer. There was no overall positive or inverse association of colorectal cancer risk with intakes of total calories, total or subclasses of fat, carbohydrate, or dietary fiber, whereas there was an inverse association with total protein. Among major food groups, there was a progressive decline in risk of colorectal cancer with increasing intake of fish and shellfish (relative risk for 4th vs. 1st quartile = 0.49, 95% confidence interval = 0.27-0.89). A similar inverse association was also observed for consumption of dairy products, and this association was explained mainly by calcium, not by other nutrients, such as fat or protein. The results of the present study indicated that certain dietary components of fish or dairy products may protect against colorectal cancer, whereas the relations with red meat or total fat remained unclear.