(HealthDay News) – Low levels of 25-hydroxyvitamin D (25[OH]D) and high levels of parathyroid hormone (PTH) are associated with increased mortality in older black and white adults, according to a study published online Aug 31 in the Journal of Clinical Endocrinology & Metabolism.
Noting that previous studies have included mainly individuals of European descent, Stephen B Kritchevsky, PhD, from Wake Forest University in Winston-Salem, NC, and colleagues analyzed data from 2,638 well-functioning black and white participants (aged 71–80 years) with measured 25(OH)D and PTH, who were part of the Health ABC prospective cohort.
The researchers found that mean 25(OH)D concentrations were significantly higher in whites than in blacks, but serum 25(OH)D concentrations by race interactions were not significant. Overall, lower 25(OH)D concentrations correlated with increased mortality in blacks and whites combined (hazard ratio of 2.27 for 25(OH)D concentrations <10ng/mL; 1.48 for 10 to <20; and 1.25 for 20 to <30, compared with levels ≥30ng/mL). Without considering 25(OH)D levels, blacks had 22% higher mortality than whites, but the association was diminished after including 25(OH)D in the model. There was also an association with PTH and mortality (hazard ratio, 1.8 for ≥70 vs. <23pg/mL).
“In conclusion, both low 25(OH)D and high PTH were independently associated with increased all-cause and cause-specific mortality in both black and white community-dwelling older adults,” the authors write. “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.”