Serum 25-hydroxyvitamin D, parathyroid hormone, and mortality in older men

Abstract

Context: Low 25-hydroxyvitamin D [25(OH)D] and high PTH may contribute to increased mortality risk in older adults.

Objective: The aim of the study was to test the association between 25(OH)D, PTH, and mortality in older men.

Design and setting: The prospective Osteoporotic Fractures in Men (MrOS) study was conducted at six U.S. clinical centers.

Participants: We studied community-dwelling men at least 65 yr old (n = 1490).

Main outcome measure: Multivariate-adjusted proportional hazards models estimated the hazard ratio (HR) for mortality; cause of death was classified as cancer, cardiovascular, and other by central review of death certificates.

Results: During 7.3 yr of follow-up, 330 (22.2%) participants died: 97 from cancer, 110 from cardiovascular disease, and 106 from other causes. The adjusted HR per sd decrease in 25(OH)D for all-cause mortality was 1.01 (95% CI, 0.89, 1.14); no association between 25(OH)D and cardiovascular or other-cause mortality was seen. Unexpectedly, lower 25(OH)D levels were modestly associated with a decreased risk of cancer mortality (adjusted HR per sd decrease, 0.80; 95% CI, 0.64, 0.99). Analyzing 25(OH)D as a categorical variable did not alter these results. Higher PTH levels (log-transformed) were associated with an increased risk of all-cause mortality (adjusted HR per sd increase, 1.15; 95% CI, 1.03, 1.29) and cardiovascular mortality (adjusted HR per sd increase in PTH, 1.21; 95% CI, 1.00, 1.45).

Conclusions: In contrast to previous studies, lower 25(OH)D levels were not associated with an increased risk of all-cause or cause-specific mortality in older men. Higher PTH levels were associated with a modest increase in mortality risk.

Figure 1

Adjusted survival plots for participants in the MrOS study, by quartile of total intact PTH or 25(OH)D. Plots are adjusted for age, clinic, season of blood draw, serum calcium and phosphate, GFR, percentage body fat, weight, race, health status, presence of at least one medical condition, alcohol use, education, activity level (PASE score), marital status, and presence of a functional or mobility limitation.