Vitamin D and calcium intake have been suggested to have protective effects against breast cancer; however, the data have been inconclusive. The present meta-analysis examined the overall effects of vitamin D intake, circulating 25(OH)D and 1alpha,25(OH)(2)D levels, and calcium intake on breast cancer risk.
Data from 11 studies on vitamin D intake, 7 studies on circulating 25(OH)D levels, 3 studies of circulating 1alpha,25(OH)(2)D levels, and 15 studies on calcium intake and breast cancer risk were included in this analysis.
From the meta-analysis:
• There was a significant inverse relationship between vitamin D intake and breast cancer risk [more intake, less risk], with an overall relative risk (RR) of high versus low vitamin D intake for breast cancer of 0.91 (95% CI = 0.85-0.97).
• The highest quantile [subset] of circulating 25(OH)D was found to be associated with a 45% (OR = 0.55, 95% CI = 0.38-0.80) decrease in breast cancer when compared with the lowest quantile.
• No significant association for the circulating 1alpha,25(OH)(2)D level and breast cancer was found (OR = 0.99, 95% CI = 0.68-1.44).
• For calcium, a 19% (RR = 0.81, 95% CI = 0.72-0.90) decrease in breast cancer risk was found for those with highest quantile of calcium intake compared to the lowest quantile.
These results provide strong evidence that vitamin D and calcium have a chemopreventive effect against breast cancer.
Source: Breast Cancer Research and Treatment, Oct 23, 2009. PMID: 19851861, by Chen P, Hu P, Xie D, Qin Y, Wang F, Wang H. Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China. [E-mail: email@example.com]