Blood 25-Hydroxyvitamin D3 Concentrations and Incident Sporadic Colorectal Adenoma Risk: A Pooled Case-Control Study

The authors examined the association between circulating 25-hydroxyvitamin D-3 (25(OH)D-3), the best indicator of total vitamin D exposure, and incident, sporadic colorectal adenoma risk in a pooled analysis of primary data from 3 colonoscopy-based case-control studies conducted in Minnesota, North Carolina, and South Carolina between 1991 and 2002. The pooled study included 616 colorectal adenoma cases and 770 polyp-free controls. Multivariable logistic regression was used to estimate the association between circulating 25(OH)D-3 and colorectal adenoma risk. Stratified analyses and the likelihood ratio test were used to examine effect modification by various risk factors. In the pooled analysis, higher circulating 25(OH)D-3 concentrations were statistically significantly associated with decreased colorectal adenoma risk (highest vs. lowest quartile odds ratio = 0.59, 95% confidence interval: 0.41, 0.84). The observed inverse association was stronger among participants who used nonsteroidal antiinflammatory drugs regularly (highest vs. lowest quartile odds ratio = 0.33, 95% confidence interval: 0.19, 0.56). Inverse associations between 25(OH)D-3 and colorectal adenoma did not differ substantially by other risk factors or by adenoma characteristics. These findings support the hypothesis that greater vitamin D exposure may reduce the risk of colorectal adenoma and suggest that it may do so more strongly in combination with antiinflammatory agents.