title: Intake of vitamin D and risk of breast cancer--a meta-analysis.
abstract: Vitamin D insufficiency has been shown to be associated with a number of conditions including diabetes, multiple sclerosis and the overall risk of cancer. We aimed at studying the association between vitamin D intake and risk of breast cancer in a meta-analysis. We searched Pubmed, Embase, and Web of Science using the MESH terms "vitamin D" and "breast cancer". A total of 1731 studies were identified, but only 6 studies contained original data on the association between intake of vitamin D and risk of breast cancer. Overall there was no association between amount of vitamin D and risk of breast cancer (RR=0.98, 95% CI: 0.93-1.03, test for heterogeneity p<0.01). However, most studies reported on very low intakes of vitamin D (typically in the range 100-400 IU/day). Restricting the analyses to intakes > or =400 IU/day yielded a more homogenous result with a trend towards less breast cancer with > or =400 IU/day vs. the lowest intake (typically <50-150 IU/day), RR=0.92, 95% CI: 0.87-0.97, p for heterogeneity 0.14. In conclusion there may be a trend towards fewer cases of breast cancer with higher intakes of vitamin D (> or =400 IU/day). However, more research is needed, preferably in the form of randomized-controlled trials.
authors.affiliation: The Osteoporosis Clinic, Aarhus Amtssygehus, Aarhus University Hospital, Tage Hansens Gade 2, DK-8000 Aarhus C, Denmark.
authors.forename: Tina
authors.initials: T
authors.lastname: Gissel
authors.forename: Lars
authors.initials: L
authors.lastname: Rejnmark
authors.forename: Leif
authors.initials: L
authors.lastname: Mosekilde
authors.forename: Peter
authors.initials: P
authors.lastname: Vestergaard
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D012307:Risk Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000378:metabolism; D014808:Vitamin D Deficiency / Q000378:metabolism
chemical_list: D014807:Vitamin D