Serum Vitamin D Status and Breast Cancer Risk by Receptor Status: A Systematic Review

ABSTRACT

Background: The association between vitamin D status and breast cancer risk is equivocal. No systematic reviews or meta-analyses have examined this association stratified by receptor status. Our objective is to conduct a systematic review to answer the question, “Is there a relationship between lower serum/plasma vitamin D levels and increased risk of triple negative breast cancer (TNBC) specifically?” Methods: We systematically searched Embase and PubMed databases for published original research studies examining the risk of a breast cancer diagnosis according to vitamin D status. We excluded studies that did not provide risk estimates stratified by receptor status. Results: Fourteen studies met our criteria, including case-control, nested case-control, and case-series studies, reflecting the cumulative results of 13,135 breast cancer cases. When grouped by relevancy to TNBC, the proportion of analyses across all study types showing a significant association between vitamin D status and breast cancer diagnosis was 37% for non-TNBC analyses, 48% for analyses that included some TNBC cases, and 88% for TNBC analyses. Conclusions: Our results suggest that low vitamin D status may particularly increase the risk of TNBC, although more research is needed to determine if this association is causative. Women should be routinely screened for 25(OH)D deficiency.

Acknowledgments

The first author would like to express thanks to the instructors in the Department of Nutritional Sciences, University of Cincinnati for their guidance in the development of this research.

Additional information

Funding

This systemic review was conducted as part of a master's thesis. There is no direct funding or financial support related to this article.