Richard D. Semba, from The Johns Hopkins University School of Medicine (Maryland, USA), and colleagues studied data from 13,331 men and women participating in NHANES III (The Third National Health and Nutritional Examination Survey), to ascertain the role of vitamin D levels (serum 25(OH)D) as contributors to risks of death.  The researchers found that women with blood levels of the vitamin lower than 15.3 nanograms per milliliter were more likely to die from causes such as heart disease and cancer, as compared to women with higher levels (above 27 ng/ml).  The team observes that:  “Older community-dwelling women with low [vitamin D] levels are at an increased risk of death.”  The team notes that several biologic mechanisms could explain a causal relationship between vitamin D deficiency and mortality, because the active form of vitamin D (1,25-dihydroxyvitamin D) is associated with controlling inflammatory compounds, regulating immune health and blood pressure, and reducing arterial hardening.