Folate intake and the risk of colorectal cancer in a Korean population

Background: Folate, a water-soluble B vitamin and one of the major micronutrients in vegetables, is known as an essential factor for the de novo biosynthesis of purines and thymidylate, and it plays an important role in DNA synthesis and replication. Thus, folate deficiency results in ineffective DNA synthesis, and has been shown to induce the initiation and progression of colorectal cancer (CRC). Recently, the incidence of CRC in Korea has increased markedly in both men and women; this trend may be related to the adoption of a more 'westernized' lifestyle, including dietary habits. Objective: A hospital-based case-control study was conducted to examine the relationship between folate intake and the risk of CRC within a Korean population. Methods: A total of 596 cases and 509 controls, aged 30-79 years, were recruited from two university hospitals. Site- and sex-specific odds ratios (ORs) were estimated using logistic regression models. Results: Cases were more frequently found to have a family history of CRC among first-degree relatives, to consume more alcohol, to be more likely current smokers and less likely to participate in vigorous physical activity than the controls. In the overall data for men and women combined, multivariate ORs (95% confidence interval (CI), P for trend) comparing the highest vs the lowest quartile of dietary folate intake were: 0.47 (0.32-0.69,