Calcium, dietary, and lifestyle factors in the prevention of colorectal adenomas

Abstract

BACKGROUND.Many studies have suggested a role for calcium in reducing the risk of colorectal adenomas and cancer but its effectiveness may be dependent on interactions with other dietary and/or lifestyle factors. We examined the association between calcium and prevalence of adenomas and assessed whether the association was stronger in biologically plausible subgroups.METHODS.Cross‐sectional data from 222 cases and 479 adenoma‐free controls who underwent colonoscopies and completed food frequency and lifestyle questionnaires were used in the analyses. Multivariable logistic regression was used to estimate the association between calcium and prevalence of adenomas. Stratified analyses and the likelihood ratio test were used to examine effect modification by various demographic, lifestyle, and behavioral factors.RESULTS.Overall, little association was observed comparing total calcium intake of ≥900 mg/day to <500 mg/day (adjusted odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.53–1.37). However, stronger associations were observed in patients with lower fat intake and in those who regularly (≥15 times/month) took nonsteroidal antiinflammatory drugs (NSAIDs). Specifically, total calcium intake of ≥900 mg/day was associated with a lower prevalence of adenomas among patients with lower fat intake (OR = 0.47, 95% CI: 0.25–0.91) but not among those with higher fat intake (OR = 1.20, 95% CI: 0.61–2.35; P‐value for interaction = .01). For NSAIDs, the associations were OR = 0.37 (95% CI: 0.16–0.86) for regular NSAID users and OR = 1.27 (95% CI: 0.73–2.22) with infrequent or nonuse of NSAIDs, respectively (P = .06).CONCLUSIONS.The data suggest that a lower‐fat diet and regular NSAID use may enhance calcium's effectiveness as a colorectal cancer preventive agent. Cancer 2007 © 2007 American Cancer Society.

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).…”

Vitamin D and Prevention of Colorectal Adenoma: A Meta-analysis

“…Eight studies that examined the relationship between circulating 25(OH)D and colorectal adenomas were identified, including four case-control studies (15,29,31,32), one nested case-control study (33), two cohort studies (14,26), and one cross-sectional study (34). Seven of the eight studies identified were included in this analysis ( (29).…”

“…Seven of the eight studies identified were included in this analysis ( (29). Six studies accounted for season of blood draw: one study matched controls by date of blood draw (33), and five studies (14,15,26,31,34) adjusted for month of blood draw. One study did not adjust for seasonality (29).…”