Racial differences in the association of serum 25-hydroxyvitamin D concentration with coronary heart disease events

Abstract

Importance: Low circulating concentrations of 25-hydroxyvitamin D (25[OH]D) have been consistently associated with an increased risk of coronary heart disease (CHD) in white populations. This association has not been rigorously evaluated in other races or ethnicities, in which the distributions of 25(OH)D concentration and possibly other aspects of 25(OH)D metabolism differ.

Objective: To examine the association of serum 25(OH)D concentration with risk of CHD in a multiethnic population.

Design, setting, and participants: We studied 6436 participants in the Multi-Ethnic Study of Atherosclerosis (MESA), recruited from July 2000 through September 2002, who were free of known cardiovascular disease at baseline. We measured baseline serum 25(OH)D concentrations using a mass spectrometry assay calibrated to established standards. We tested associations of 25(OH)D with adjudicated CHD events assessed through May 2012.

Main outcome and measures: Primary outcome measure was time to first adjudicated CHD event, defined as myocardial infarction, angina, cardiac arrest, or CHD death.

Results: During a median follow-up of 8.5 years, 361 participants had an incident CHD event (7.38 events per 1000 person-years). Associations of 25(OH)D with CHD differed by race/ethnicity (P for interaction < .05). After adjustment, lower 25(OH)D concentration was associated with a greater risk of incident CHD among participants who were white (n = 167 events; hazard ratio [HR], 1.26 [95% CI, 1.06-1.49] for each 10-ng/mL decrement in 25(OH)D) or Chinese (HR, 1.67 [95% CI, 1.07-2.61]; n = 27). In contrast, 25(OH)D was not associated with risk of CHD in participants who were black (HR, 0.93 [95% CI, 0.73-1.20]; n = 94) or Hispanic (HR, 1.01 [95% CI, 0.77-1.33]; n = 73).

Conclusions and relevance: Lower serum 25(OH)D concentration was associated with an increased risk of incident CHD events among participants who were white or Chinese but not black or Hispanic. Results evaluating 25(OH)D in ethnically homogeneous populations may not be broadly generalizable to other racial or ethnic groups.

Figure. Race/Ethnicity-Specific Associations of 25-HydroxyvitaminD, Examined as a Continuous Variable, with Incident Coronary Heart Disease Events

The smooth spline estimates the hazard ratio of the combined coronary heart disease event, according to annualized serum concentrations of 25(OH)D (nanograms per milliliter). Splines are adjusted for age, sex, and study site. Dotted lines represent 95% confidence intervals. Below each spline is the histogram of the distribution of serum 25(OH)D concentration.