Research published in the Journal of Clinical Endocrinology and Metabolism reports low vitamin D levels and high parathyroid hormone levels are associated with increased mortality among African American and Caucasian elderly.
Past research on the vitamin D has examined the relationship between vitamin D status and mortality among individuals of European descent only.
Dr Stephen Kritchevsky and colleagues measured serum vitamin D levels as well as parathyroid hormone (PTH) for 2,638 well-functioning, community-dwelling African American (AA) and Caucasian (CA) men and women aged 71-80 years. The participants were contacted every 6 months for in-person examinations or telephone interviews to assess their medical condition. The authors calculated the number of deaths among participants with differing vitamin D levels.
Mean vitamin D status was higher among CAs (29 ng/mL) than AAs (20.8 ng/mL). The researchers found that only 15.4% of AA participants had vitamin D levels >30 ng/mL compared with 42.8% of Caucasians. Vitamin D levels <20 ng/mL were observed in one third of all participants. Elevated PTH (≥70 pg/mL) was associated with all cause mortality in both groups compared with levels less than 23 pg/mL; however, the increased risk in AAs wasn’t statistically significant.
The authors report that low 25(OH)D status (< 30 ng/mL) and high PTH were both associated with a significantly increased risk of all cause mortality. “When 25(OH)D and PTH were included together in the fully adjusted model, both independently predicted all-cause mortality,” They explained.
The association between vitamin D status and mortality persisted after adjusting for physical function, disease biomarkers, health behaviors, and prevalent chronic conditions. Dr Kritchevsky concludes,
“Although this study cannot establish causality, the potential impact of remediating low 25(OH)D concentrations is greater in Blacks than whites because low 25(OH)D concentrations are more common in Blacks. Randomized trials will be required to evaluate the ability of vitamin D supplementation to reduce mortality disparities between Black and white older adults.”