Dietary and serum vitamins A and E and colorectal cancer risk in Chinese population: a case-control study

The effect of vitamin A (VA) and vitamin E (VE) on colorectal cancer (CRC) risk is controversial. The aim of this study is to examine the association between serum concentrations and dietary intakes of VA and VE and the risk of CRC in Guangdong, China. A total of 535 cases and 552 sex and age-matched (5-year interval) controls were recruited during July 2010 to September 2014. Dietary information was assessed by face-to-face interviews using a validated food frequency questionnaire. Concentrations of VA and VE were measured by high-performance liquid chromatography. Multivariable logistic regression was used to estimate the odds ratios (ORs) and 95% confidence interval (CI) after adjusting for various potential confounders. A higher intake of VA and VE was found to be associated with 52 and 43% reduction in CRC risk. The ORs of the highest quartile compared with the lowest quartile intake were 0.48 (95% CI: 0.31, 0.73, P-trend<0.01) for VA and 0.57 (95% CI: 0.37, 0.88, P-trend<0.01) for VE. An inverse association was also found between serum retinol and CRC risk, with an adjusted OR (95% CI) of 0.28 (0.19-0.43) (P-trend<0.01). However, no statistically significant association was found between serum alpha-tocopherol and CRC risk. Stratified analysis by sex showed that serum retinol and dietary VA and VE were inversely associated with CRC risk in both sexes. This study supported the hypothesis that lower serum levels of retinol and lower intakes of VA and VE were associated with the risk of CRC in a Chinese population.