Colorectal
adenomas are clear precursors of
cancer; hyperplastic
polyps may also have malignant potential. An inverse association between circulating
vitamin D metabolites and
adenoma risk has been reported, but less is known about
vitamin D and hyperplastic
polyps. We conducted a case-control study of
adenomas and hyperplastic
polyps among 459 members of an integrated health plan evaluated via colonoscopy. Questionnaires provided information on colorectal
polyp risk factors, and plasma samples were assayed for 25-hydroxyvitamin-D [25(
OH)D]. Polytomous regression was used to estimate odds ratios for
adenomas (n = 149) and hyperplastic
polyps (n = 85) compared to
polyp-free controls (n = 225) by tertile of 25(
OH)D. An inverse association between 25(
OH)D and
adenomas was suggested after adjustment for potential confounding factors [comparing upper to lower tertiles, OR (95%CI): 0.71 (0.38-1.30)]. After restriction of the analyses to study participants with no history of
polyps, this OR estimate was reduced further [adjusted OR (95%CI): 0.52 (0.23-1.20)]. In comparison, no inverse association between hyperplastic
polyps and 25(
OH)D was observed among the full study participants [adjusted OR (95%CI): 1.17 (0.55-2.51)] or among those without prior
polyps [adjusted OR (95%CI): 1.42 (0.55-3.65)]. Our study suggests that the established inverse association between circulating 25(
OH)D and
adenoma may not apply to hyperplastic
polyps.