A study conducted by researchers at the University of California, San Diego School of Medicine and published yesterday in the American Journal of Public Health indicates that persons with lower blood levels of vitamin D may be twice as likely to die prematurely as people with higher blood levels of vitamin D. The study was based on a systematic review of 32 previous studies that included analyses of vitamin D, blood levels, and human mortality rates. The specific variant of vitamin D assessed was 25 hydroxyvitamin D, the primary form found in blood.
“Three years ago, the Institute of Medicine (IOM) concluded that having a too-low blood level of vitamin D was hazardous,” says Cedric Garland, DrPH, lead author of the study. “This study supports that conclusion, but goes one step further. The 20 nanograms per milliliter (ng/ml) blood level cutoff assumed from the IOM report was based solely on the association of low vitamin D with risk of bone disease. This new finding is based on the association of low vitamin D with risk of premature death from all causes, not just bone diseases.”
Garland says the blood level amount of vitamin D associated with about half of the death rate was 30 ng/ml. He notes that two-thirds of the U.S. population has an estimated blood vitamin D level below 30 ng/ml. The average age when the blood was drawn in this study was 55 years; the average length of follow-up was nine years. The study included residents of 14 countries, including the United States, and data from 566,583 participants. Read the study abstract.
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