Higher serum vitamin D [25(OH)D] concentrations have been associated with lower risk of multiple cancer types. Researchers investigated whether previously reported inverse association between 25(OH)D and cancer risk could be replicated, and if a 25(OH)D response region could be identified among women 55 and older across a broad range of 25(OH)D concentrations. Data from two cohorts representing different median 25(OH)D concentrations were pooled to afford a broader range of concentrations. The analysis of over 2300 women included all invasive cancers excluding skin cancer. Breast cancer was the most common type of cancer diagnosed during the study (43% of all cancers in the pooled cohort). Results show that cancer incidence was substantially lower at higher concentrations of 25(OH)D with women with concentrations ≥40 ng/ml having a 67% lower risk of cancer than women with concentrations ≤20 ng/ml.
McDonnell SL, et al. Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml Are Associated with >65% Lower Cancer Risk: Pooled Analysis of Randomized Trial and Prospective Cohort Study. PLOS ONE doi:10.1372/journal.pone.0152441 April 6, 2016