Abstract
Calcium intake has been consistently, modestly inversely associated with colorectal neoplasms, and supplemental calcium reduced adenoma recurrence in clinical trials. Milk products are the major source of dietary calcium in the United States, but their associations with colorectal neoplasms are unclear. Data pooled from three colonoscopy-based case-control studies of incident, sporadic colorectal adenoma (n = 807 cases, 2,185 controls) were analyzed using multivariable unconditional logistic regression. Residuals from linear regression models of milk with dietary calcium were estimated as the noncalcium, insulin-like growth factor 1-containing component of milk. For total, dietary, and supplemental calcium intakes, the adjusted odds ratios (ORs) comparing the highest to the lowest intake quintiles were 0.94 (95% confidence interval [CI] 0.69-1.30), 0.86 (CI 0.62-1.20), and 0.99 (CI 0.77-1.27), respectively. The corresponding ORs for consumption of total milk products, total milk, nonfat milk, total milk product residuals, and nonfat milk residuals were, respectively, 0.99, 0.90, 0.92, 0.94, and 0.95; all CIs included 1.0. For those who consumed any whole milk relative to those who consumed none, the OR was 1.15 (CI 0.89-1.49). These results are consistent with previous findings of modest inverse associations of calcium intakes with colorectal adenoma, but suggest that milk products may not be associated with adenoma.