Recent epidemiologic studies have generally reported a modest inverse association between calcium intake and the risk of colorectal cancer. However, findings pertaining to specific subsites in the colorectum have been conflicting.
Our objective was to prospectively examine the relations between intakes of calcium and dairy foods and the risk of colorectal cancer, overall and by anatomic subsite, in men from the Cohort of Swedish Men.
In 1997, 45 306 men aged 45-79 y and without a history of cancer completed a food-frequency questionnaire. The men were followed through 31 December 2004.
During a mean follow-up of 6.7 y, we ascertained 449 incident cases of colorectal cancer. After adjustment for age and other known or potential risk factors, the multivariate rate ratio (RR) of colorectal cancer for men in the highest quartile of total calcium intake compared with those in the lowest quartile was 0.68 (95% CI: 0.51, 0.91; P for trend = 0.01). A high consumption of dairy foods was also associated with a lower risk of colorectal cancer. The multivariate RR of colorectal cancer for > or = 7 servings/d of total dairy foods compared with <2 servings/d was 0.46 (0.30, 0.71; P for trend = 0.01). For cancer subsites, the corresponding RRs were 0.37 (0.16, 0.88) for proximal colon, 0.43 (0.20, 0.93) for distal colon, and 0.48 (0.23, 0.99) for rectum.
Our findings provide support for inverse associations between intakes of calcium and dairy foods and the risk of colorectal cancer.