Lee KJ, Inoue M, Otani T, Iwasaki M, Sasazuki S, Tsugane S. Physical activity and risk of colorectal cancer in Japanese men and women: The Japan Public Health Center-based prospective study. Cancer Causes Control. 2007;18:199-209
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Tokyo, Japan. Cancer Causes and Control
(Impact Factor: 2.74).
04/2007; 18(2):199-209. DOI: 10.1007/s10552-006-0098-3
To prospectively examine the association between physical activity and the risk of developing colorectal cancer in a large population-based cohort study of Japanese men and women, and to investigate whether the effects of physical activity on colorectal cancer risk differ by sex and subsite.
We analyzed data from a population-based cohort of 65,022 subjects. A total of 486 incident colorectal cancers (154 proximal colon, 166 distal colon and 149 rectal cancers) was identified during 6 years of follow-up.
We observed a significant inverse association between physical activity and the risk of developing colorectal cancer, particularly colon cancer, among men. Relative to men in the lowest level of metabolic equivalent (MET) hours per day, those in the highest level had a RR of 0.69 (95% CI = 0.49-0.97). A significant decrease in risk of colorectal cancer was associated with increasing MET hours per day among men. This inverse association was essentially limited to colon cancer. A significant decrease in risk with increasing MET-hour score was observed predominantly for proximal colon cancer among men. In contrast, no significant decrease was seen among women.
These findings suggest that physical activity may prevent colon cancer among Japanese men.
Available from: Trude Eid Robsahm
- "Two studies reported a statistically significant inverse association between physical activity and cancer of the proximal colon (Friedenreich et al., 2006; Lee et al., 2007). The EPIC study showed a reduced risk of cancer for the highest level of physical activity compared with the lowest level for both sexes combined (Friedenreich et al., 2006), and an even stronger association was observed for the men of the Japan Public Health Study (Lee et al., 2007). For the distal colon and rectum, no studies reported statistically significant associations. "
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ABSTRACT: Several studies report varying incidence rates of cancer in subsites of the colorectum, as an increasing proportion appears to develop in the proximal colon. Varying incidence trends together with biological differences between the colorectal segments raise questions of whether lifestyle factors impact on the risk of cancer differently at colorectal subsites. We provide an updated overview of the risk of cancer at different colorectal subsites (proximal colon, distal colon, and rectum) according to BMI and physical activity to shed light on this issue. Cohort studies of colorectal cancer, published in English throughout 2010, were identified using PubMed. The risk estimates from 30 eligible studies were summarized for BMI and physical activity. A positive relationship was found between BMI and cancer for all colorectal subsites, but most pronounced for the distal colon [relative risk (RR) 1.59, 95% confidence interval (CI) 1.34-1.89]. For the proximal colon and rectum, the risk estimates were 1.24 (95% CI 1.08-1.42) and 1.23 (95% CI 1.02-1.48), respectively. Physical activity was related inversely to the risk of cancer at the proximal (RR 0.76, 95% CI 0.70-0.83) and distal colon (RR 0.77, 95% CI 0.71-0.83). Such a relationship could not be established for the rectum (RR 0.98, 95% CI 0.88-1.08). In conclusion, the results suggest minor differences in the associations of BMI and the risk of cancer between the colorectal subsites. For physical activity, the association does not seem to differ between the colonic subsites, but a difference was observed between the colon and the rectum, perhaps indicating that different mechanisms are operating in the development of colon and rectal cancer.
Available from: PubMed Central
- "For instance, Samad and associates identified both occupational and recreation physical activity variables as leading to lower colon cancer risk for men and women when combining results from 19 cohort studies.16 Similar to the findings reported on breast cancer risk reduction, Lee and colleagues found a significant negative relationship between more strenuous exercise or daily physical work and the risk of developing colon cancer in a cohort of Japanese men.30 In addition, physical activity has also been shown to improve QOL within this cancer population. "
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ABSTRACT: According to recent published reports, over 12 million new cases of cancer were estimated worldwide for 2007. Estimates from 2008 predict that cancer will account for 22.8% of all deaths in the US. Another report stated 50% to 75% of cancer deaths in the US are related to smoking, poor dietary choices, and physical inactivity. A 2004 report indicated obesity and/or a sedentary lifestyle increases the risk of developing several types of cancer. Conversely, several large-scale cohort studies point to the positive relationship between physical activity and a reduction in cancer risk. In addition, research over the last few years has clearly shown cardiorespiratory benefits, increases in quality of life (QOL), and increases in physical functioning for cancer survivors who engage in exercise programs. Thus, the purpose of this review is to highlight three areas related to cancer and physical activity. First, information concerning the prevention of cancer through physical activity is addressed. Second, recent studies identifying changes in volume of oxygen uptake (VO(2)) and/or cardiorespiratory functioning involving exercise with cancer survivors is presented. Third, studies identifying changes in cancer survivors' physical functional capacity and QOL are presented. Finally, a summary of the review is offered.
Available from: Kristiann C Heesch
- "The highest proportion of statistically significant associations for any endpoint was 60% (3 of 5 analyses) for CRC. In these analyses (Wu et al., 1987; Ballard-Barbash et al., 1990; Lee et al., 2007) the associations were statistically significant for men but not women. "
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ABSTRACT: This review evaluated the strength of the evidence for a causal relationship between physical activity (PA) and colorectal cancer (CRC). A systematic review of databases through February 2008 was conducted to identify studies that assessed the association between total or recreational PA and incidence or mortality of CRC (including CRC, rectal cancer, colon cancer, and proximal or distal colon cancer). Studies were evaluated for significant associations between PA and risk of CRC endpoints and for evidence of dose-response relationships in the highest quality studies. Twenty cohort studies were evaluated; 11 were high-quality. Fifty percent of all studies and 64% of highest quality studies reported at least one significant association between PA and risk of a CRC endpoint (P<0.05). However, only 28% of all analyses (31% of analyses of highest quality studies) were significant (P<0.05). Only 40% of analyses of highest quality studies resulted in a significant P for trend (P<0.05); however, a non-significant inverse linear association between PA and colon cancer risk was apparent. Heterogeneity in the evidence from all studies and from the highest quality studies was evident. Evidence from cohort studies is not sufficient to claim a convincing relationship exists between PA and CRC risk.
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