To examine associations of serum carotenoids, retinol, and tocopherols with colorectal cancer risk, we conducted a case-control study nested within the Japan Collaborative Cohort Study. These micronutrients were measured in prediagnostic sérum samples from 116 men and women who developed colorectal cancer during an 8-yr follow-up period and from 298 matched controls. In men, the higher level of serum total carotenoids was associated with a decreased risk: The multivariate-adjusted odds ratio (OR) for the highest vs. the lowest tertile was 0.34 (95% confidence interval [CI] = 0.11-1.00; trend P over tertiles = 0.040). In women, the higher levels of α- and β-carotenes and total carotenoids were instead related to an increased risk: The corresponding ORs were 4.72 (95% CI = 1.29-17.3), 2.00 (0.70-5.73), and 2.47 (0.73-8.34), respectively (trend P = 0.007, 0.040, and 0.064, respectively). We also found a somewhat decreasing risk with increased serum retinal in all subjects and α-tocopherol in men: The ORs (95% CI) for the highest tertiles were 0.29 (0.11-0.78; trend P over tertiles = 0.010) and 0.29 (0.07-1.17; trend P = 0.098), respectively. The effects of some carotenoids on colorectal cancer risk may be modified by sex or by factors associated with sex, including smoking and drinking habits.
All Science Journal Classification (ASJC) codes
- Medicine (miscellaneous)
- Nutrition and Dietetics
- Cancer Research