Physical Activity and Occupational Risk of Colon Cancer in Shanghai, China

Division of Cancer Etiology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
International Journal of Epidemiology (Impact Factor: 9.18). 03/1993; 22(1):23-9. DOI: 10.1093/ije/22.1.23
Source: PubMed


Using occupational data for over 2000 colon cancer cases diagnosed between 1980 and 1984 in Shanghai, and employment information from the 1982 census for the Shanghai population, standardized incidence ratios (SIR) were computed for occupational groups classified by job types and physical activity levels. Men employed in occupations with low physical activity levels had modest but significantly elevated risks of colon cancer. SIR for jobs with low activity based on sitting time was 121 (95% confidence interval, Cl: 108-135) and based on energy expenditure was 126 (95% Cl: 115-138). Corresponding SIR for women were 99 (95% Cl: 83-118) and 113 (95% Cl: 100-127). The data were also used to screen for specific occupations with elevated SIR to generate leads to occupational colon cancer. Increased incidence was observed for professional and other white collar workers, and male chemical processors and female textile workers. The findings add to the emerging evidence that workplace activity may influence the risk of this common cancer.

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    • "Otherwise, peristalsis of the intestines is promoted or increased by the increased synthesis of prostaglandin within the body.3 Hormones involved in the synthesis of bile acid, cholesterol converted into the bile acid in the liver, and substances involved in tumor growth, such as interleukin-1, are affected by physical exercise.4-6 According to White et al,2 regarding the correlation between PA and the pathogenesis of colorectal cancer, the risks of developing colorectal cancer were decreased in women aged 45 years or older who did physical activities for more than 4 hours a week, including walking or riding a bicycle, as compared with those who maintain daily lives in a sitting position. "
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    ABSTRACT: Physical activity (PA) is associated with a reduced risk of colorectal cancer. Thus, we examined the colon transit time (CTT) according to the physical activity level (PAL) in Korean adults. The study subjects were 49 adults: 24 males and 25 females. The subjects used an accelerometer for 7 consecutive days to measure the 1-week PAL. The subjects took a capsule containing 20 radio-opaque markers for 3 days. On the fourth day, a supine abdominal radiography was performed. According to the total activity count of all study subjects, the upper 25%, middle 50% and lower 25% were classified into the high (H), moderate (M) and low (L) physical activity (PA) groups, respectively. The total CTT was significantly longer in the female (25.8 hours) than in the male subjects (7.4 hours) (P = 0.002). In regard to difference on PAL, although there was no significant difference among the male subjects, the right CTT in the female subjects was significantly shorter in H group than in M group (P = 0.048), and the recto-sigmoid CTT was significantly shorter in H group than in L group (P = 0.023). Furthermore, there were significant differences in total CTT between L and M groups (P = 0.022), M and H groups (P = 0.026) and between L and H groups (P = 0.002). The female, but not male, subjects showed that moderate and high PAL assisted colon transit.
    Journal of neurogastroenterology and motility 01/2012; 18(1):64-9. DOI:10.5056/jnm.2012.18.1.64 · 2.30 Impact Factor
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    • "Occupational physical activity was assessed by using a job exposure matrix, which assigned occupation codes into categories of low, medium, and high sitting time and low, medium, and high energy expenditure. Criteria for classification of the total of 300 specific occupation codes in the study were used in earlier surveys and have been modified by industrial hygienists based on the work environments in China (Vetter et al, 1992; Chow et al, 1993; Zheng et al, 1993). Categories of sitting time were defined as jobs with low (<20% of working hours), medium (20–80%), and high (>80%) sitting time. "
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    ABSTRACT: The influence of different types and intensities of physical activity on risk for breast cancer is unclear. In a prospective cohort of 73,049 Chinese women (40-70 years), who had worked outside the home, we studied breast cancer risk in relation to specific types of self-reported and work history-related physical activity, including adolescent and adult exercise and household activity and walking and cycling for transportation. Occupational sitting time and physical activity energy expenditure were assigned based on lifetime occupational histories. In all, 717 incident breast cancer cases were diagnosed. Breast cancer risk was lower for women in the lowest quartile of average occupational sitting time and in the highest quartile of average occupational energy expenditure (adjusted hazard ratio (HR): 0.81 and 0.73, respectively, P ≤ 0.05). Adult exercise at or above the recommended level (8 metabolic equivalent (MET) h per week per year) was associated with lower risk (adjusted HR: 0.73, P<0.05) in post-menopausal women. Analysis of joint effects showed that having both an active job and exercise participation did not confer an additional benefit. Other common daily activities were not associated with lower risk. These findings suggest that both exercise and occupational activity are associated with lower breast cancer risk, which supports current health promotion campaigns promoting exercise.
    British Journal of Cancer 09/2011; 105(9):1443-50. DOI:10.1038/bjc.2011.370 · 4.84 Impact Factor
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Wei Zheng