Fermented dairy products, dietary calcium and colon cancer: a case-control study in The Netherlands.

To examine whether the consumption of fermented dairy products or the dietary intake of calcium decreases colon cancer risk, a case-control study was conducted in the The Netherlands. Dietary patterns were assessed in detail (for cases before diagnosis or symptoms occurred) using a structured dietary history questionnaire. After adjustment for potential confounding variables, consumption of fermented dairy products, hard cheese and unfermented dairy products was not significantly associated with risk of colon cancer: an odds ratio (OR) of 1.1 was found for individuals consuming more than one serving of fermented dairy products per day as compared to those consuming less than 10% of one serving a day. Adjustment for dietary calcium attenuated the associations. Total dietary calcium was positively but non-significantly associated with colon cancer risk after adjustment for age, gender, urbanization level and total energy intake. Additional adjustment for a positive family history of colorectal cancer, cholecystectomy and energy-adjusted intake of total fat, dietary fibre, vitamin C and alcohol increased the association. No differences were observed between calcium from fermented and from unfermented dairy sources. The observed associations for fermented dairy products and dietary calcium differed between men and women: positive significant associations were observed in men, while in women non-significant inverse associations were found. Our results do not support the hypothesis that an increased intake of commercially available, commonly used fermented dairy products or dietary calcium decreases the risk of colon cancer.