Serum 25-Hydroxyvitamin D, Dietary Calcium Intake, and Distal Colorectal Adenoma Risk

Abstract

Vitamin D has recently emerged as a potentially protective agent against colorectal neoplasia. We assessed the associations between dietary vitamin D, plasma 25-hydroxyvitamin D [25(OH)D], dietary calcium, and colorectal adenomas in a large screening sigmoidoscopy-based case-control study in Southern California. Because conversion of serum 25(OH)D to serum 1,25-vitamin D is highly regulated by serum calcium, we also assessed modification of the 25(OH)D-adenoma association by calcium intake. Cases were 473 subjects with a primary adenoma, and controls were 507 subjects who had no adenomas at sigmoidoscopy and no history of adenomas. Compared with those in the lowest quartile of intake, those in the highest quartile of dietary vitamin D had an adjusted odds ratio (OR) of 0.83 [95% confidence interval (CI) = 0.49-1.41] and those in the highest quartile of dietary calcium had an OR of 0.82 (95% CI = 0.49-1.25). There was a suggestion that plasma 25(OH)D may be protective in this population (OR for highest vs. lowest quartile = 0.74, 95% CI = 0.51-1.09). A significant protective effect of 25(OH)D was clearly evident only in those with calcium intakes below (OR = 0.40 for highest vs. lowest quartile, 95% CI = 0.22-0.71, p for trend = 0.005) and above (OR = 1.17, 95% CI = 0.69-1.99, p for trend = 0.94) the median calcium intake.

Serum 25(OH)D levels, dietary intake of vitamin D, and colorectal adenoma recurrence

“…The results of this study are in agreement with some reports in the literature where no significant effect for serum 25(OH)D and colorectal adenoma [16,17], or cancer [18] was observed. However, others [2,3,10] have reported statistically significant inverse associations between serum 25(OH)D and colorectal neoplasia, most recently the report from the Women's Health Initiative (WHI) [10].…”

Sun exposure may protect against non‐Hodgkin lymphoma: A case‐control study

“…51 There is also evidence that 1,25D 3 induces apoptosis and inhibits angiogenesis and tumour spread. 49,52 There is evidence too that plasma concentration of vitamin D is inversely associated with risk of colorectal and prostate cancers, [53][54][55][56] and some evidence that sun exposure may protect against these cancers. 57,58 Vitamin D synthesis in humans requires exposure of the skin to solar radiation and body levels of vitamin D are primarily determined by UV-mediated synthesis in skin even in high-latitude countries.…”

Calcium intake and colorectal adenoma risk: Dose‐response meta‐analysis of prospective observational studies

“…A total of 14 studies 11,[14][15][16][27][28][29][30][31][32][33][34][35][36] were eligible for the inclusion in dose-response meta-analysis of total calcium intake and adenoma risk (Supporting Information Table 2). Across the studies, types of adenomas investigated varied.…”

“…While accumulating evidence suggests that calcium may be more protective against advanced adenomas, 9,11,16,29,35 there is no sufficient a priori evidence to suspect that the effect of calcium may differ by recurrent versus occurrent adenomas. Thus, doseresponse meta-analysis of total calcium intake and adenoma risk was based on 13 studies 11,[14][15][16][28][29][30][31][32][33][34][35][36] excluding the study by Lieberman et al, 27 which was included only in the subgroup analysis for high-risk adenomas.…”

“…Out of the 13 studies, 11,[14][15][16][28][29][30][31][32][33][34][35][36] eight studies 11,14,16,29,31,[34][35][36] qualified for prospective studies, including a total of 11,005 cases with category-specific midpoints of total calcium intake ranging from 333 to 2,229 mg/day; the remaining five studies were classified as retrospective studies (2,401 cases, range 5 285-1,405 mg/day).…”