Vitamin D deficiency connected to higher mortality risk

A lack of vitamin D might increase mortality risk, according to researchers.

Previous research has demonstrated connections between mortality risk and vitamin D deficiency. The current study, according to researchers, supports a causal relationship while underscoring the importance of health strategies to keep the general public at healthy vitamin D levels.

Joshua P. Sutherland, BHSc Nut Med (Hons), a PhD candidate with the University of South Australia, and colleagues conducted a nonlinear Mendelian randomization study using data from the U.K. Biobank. The results were recently published in Annals of Internal Medicine.

The researchers assessed data from 307,601 participants aged 37 to 73 years, including genetic data and available measurements of 25-hydroxyvitamin D (25-[OH]D). They estimated genetically predicted 25-(OH)D using 35 confirmed variants and collected mortality data up to June 2020.

During a 14-year follow-up period, Sutherland and colleagues identified 18,700 deaths and observed an L-shaped association between all-cause mortality and genetically predicted 25(OH)D; as vitamin D concentration rose, the risk for death decreased.

The U.S. National Academy of Medicine recommends 25-(OH)D concentrations of at least 50 nmol/L. Notably, the researchers found that participants who were severely vitamin D deficient — with concentrations less than 25 nmol/L — had a 25% increased odds for all-cause mortality (OR = 1.25; 95% CI, 1.16-1.35) compared with those who had concentrations of at least 50 nmol/L.

“Recent estimates for the prevalence of severe deficiency range from 5% to 50%, with rates varying by geographic location and population characteristics,” the researchers wrote. “Therefore, our study affirms the potential for a notable effect on premature death and the continued need for efforts to abolish vitamin D deficiency.”

Sutherland and colleagues also found evidence for an association between vitamin D deficiency and mortality from cancer, respiratory diseases and cancer (P 0.033 for all outcomes).

“The association of vitamin D deficiency with CVD, respiratory illness, and cancer is biologically plausible,” they wrote.

The researchers concluded that the study “supports a causal relationship between vitamin D deficiency and mortality.”

“Additional research needs to identify strategies that meet the National Academy of Medicine's guideline concentration of greater than 50 nmol/L and that reduce the premature risk for death associated with low vitamin D levels,” they wrote.