Prospective study on milk products, calcium and cancers of the colon and rectum

Objective: To study the relationship between consumption of milk and milk products, calcium, lactose and vitamin D and occurrence of colorectal cancers. Design: Prospective cohort study. Subjects: A total of 9959 men and women aged 15 y or older without history of cancer at baseline. During a 24y follow-up, 72 new cancers of the large bowel (38 in the colon and 34 in the rectum) were detected. Results: Consumption of milk and total milk products was suggested to be inversely related to colon cancer incidence, whereas no similar association was seen for rectal cancer. The relative risk between the highest and lowest quartiles of intake adjusted for potential confounding factors was 0.46 (95% confidence interval 0.14-1.46, P for trend 0.09) for milk and 0.37 (95% CI = 0.12 - 1.39, P for trend 0.06) for total milk products. Lactose intake showed a similar inverse relationship with colon cancer: the relative risk was 0.31 (95% CI = 0.08 - 1.15, P for trend 0.03). Intake of vitamin D or total dietary calcium was not significantly related to colorectal cancer risk, whereas calcium provided by fermented milk products was associated with increased colorectal cancer incidence; in the highest quartile the multivariate adjusted relative risk for colorectal cancer was 2.07 (95% CI = 1.00 - 4.28). Conclusions: Our results indicate that individuals showing high consumption of milk have a potentially reduced risk of colon cancer; however, the association does not appear to be due to intake of calcium, vitamin D, or to specific effects of fermented milk. Sponsorship: This study was supported by a grant from the Swedish Cancer Foundation.