Low vitamin D levels again linked to higher death risk

October 01, 2009

Low levels of vitamin D may increase the risk of dying from all causes by 150%, according to the results of a new study that included 714 independently living, elderly women between the ages of 70 to 79 who were participating in the Women's Health and Aging Studies I and II and who were followed for 6-years on average. For the study Johns Hopkins researchers worked in collaboration with scientists from Wake Forest University, National Institute on Aging, University of Pennsylvania, and Columbia University.

It was found that women with blood levels of the inactive form of Vitamin D, lower than 15.3 nanograms per millilitre were more likely to die from causes such as heart disease and cancer, than women with higher levels (above 27 ng/ml). This is not the first study of its type to show increased likelihoods of dying in the elderly who are low in the nutrient. The researchers noted that several biologic mechanisms could explain a causal relationship between vitamin D deficiency and mortality, with the vitamin’s active form (1,25-dihydroxyvitamin D) linked to a range of effects including control of inflammatory compounds, regulating immune health and blood pressure, or reducing arterial hardening. “The role that vitamin D plays in different tissues may account for the associations between vitamin D deficiency and cardiovascular disease, cancer, and mortality,” they said.

During 6 years of follow-up, 100 of the 714 women died with the main causes of death included cardiovascular disease (36 %), respiratory disease (18 %), cancer (15 %), and other causes (27 %), state the researchers. When the researchers divided women into four groups (quartiles) according to their inactive Vitamin D levels, the proportion of women who died in during those 6 years in each quartile (from lowest to highest) was 19, 13 %, 15%, and 8.1 %, said the researchers. Increasing blood levels of vitamin D were linked to increasing survival rates, with women with the lowest average 25(OH)D levels having “significantly worse survival” than women with the highest average levels of 25(OH)D. The study results are published in the journal Nutrition Research