Physical activity, water intake and risk of colorectal cancer in Taiwan: Ahospital-based case-control study

The age-adjusted mortality rates of colorectal cancer have been rising in T aiwan over the past 2 decades, and colorectal cancer is now the third leadi ng cause of cancer mortality in the county. We conducted a hospital-based c ase-control study to clarify the nature of the association between physical activity, water intake and colorectal-cancer risk in Taiwan, A total of 16 3 subjects (aged 33-80 years) with histologically confirmed primary colorec tal cancer and 163 hospital controls were enrolled during 1992, Dietary int ake, physical activity and other lifestyle activities were assessed using a comprehensive food-frequency and lifestyle-activity questionnaire. Adjuste d odds ratios (OR) and 95% confidence intervals (CI) were estimated using c onditional logistic-regression analysis. A strong inverse dose-response rel ation between increased water intake and rectal cancer was found among men after adjustment for other risk factors (p for trend = 0.0005), The OR for rectal cancer among men in the highest tertile of water intake was 0.08 (95 % CI, 0,0.02-0.35) compared with that among men in the lowest tertile (OR = I). Similar but not significant trends were seen among women (p = 0.29). T he OR for colon cancer among men with active leisure-time physical activity was 0.19 (95% Cl, 0.05-0.77) times that: among sedentary men (p for trend 0.03), However, physical activity was not associated with colon-cancer risk among women (p = 0.48), No differences in the amount of water intake were found related to level of physical activity. These findings add to the evid ence that leisure-time activity may reduce colon-cancer risk, not only in h igh-risk but also in low-risk populations, and support the potential benefi cial effect of increased wafer intake in reducing colorectal-cancer risk. ( C) 1999 Wiley-Liss, Inc.