J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):708-11.
Vitamin D and prevention of breast cancer: Pooled analysis.
* Garland CF,
* Gorham ED,
* Mohr SB,
* Grant WB,
* Giovannucci EL,
* Lipkin M,
* Newmark H,
* Holick MF,
* Garland FC.
University of California, San Diego, Department of Family and Preventive Medicine, 9500 Gilman Drive, 0631C, La Jolla, CA 92093, USA.
BACKGROUND: Inadequate photosynthesis or oral intake of Vitamin D are associated with high incidence and mortality rates of breast cancer in ecological and observational studies, but the dose-response relationship in individuals has not been adequately studied. METHODS: A literature search for all studies that reported risk by of breast cancer by quantiles of 25(OH)D identified two studies with 1760 individuals. Data were pooled to assess the dose-response association between serum 25(OH)D and risk of breast cancer. RESULTS: The medians of the pooled quintiles of serum 25(OH)D were 6, 18, 29, 37 and 48ng/ml. Pooled odds ratios for breast cancer from lowest to highest quintile, were 1.00, 0.90, 0.70, 0.70 and 0.50 (p trend less than 0.001). According to the pooled analysis, individuals with serum 25(OH)D of approximately 52ng/ml had 50% lower risk of breast cancer than those with serum less than 13ng/ml. This serum level corresponds to intake of 4000IU/day. This exceeds the National Academy of Sciences upper limit of 2000IU/day. A 25(OH)D level of 52ng/ml could be maintained by intake of 2000IU/day and, when appropriate, about 12min/day in the sun, equivalent to oral intake of 3000IU of Vitamin D(3). CONCLUSIONS: Intake of 2000IU/day of Vitamin D(3), and, when possible, very moderate exposure to sunlight, could raise serum 25(OH)D to 52ng/ml, a level associated with reduction by 50% in incidence of breast cancer, according to observational studies.
Comment: this literature is interesting for its correlation of serum levels to intake and sunlight.