Racial Differences in the Association of Serum 25-Hydroxyvitamin D Concentration With Coronary Heart Disease Events
Are low circulating concentrations of 25-hydroxyvitamin D (25[OH]D) associated with an increased risk of coronary heart disease (CHD) among non-white populations?
The Multi-Ethnic Study of Atherosclerosis (MESA), a multicenter, community-based, prospective cohort study of clinical and subclinical cardiovascular disease, was used for the present analysis. From 2000 to 2002, MESA enrolled 6,814 adults, ages 45-84 years, with no prior history of cardiovascular disease, from six field centers. The present analysis included only subjects with baseline serum concentrations of 25(OH)D. Subjects with elevated serum 25(OH)D concentrations suggestive of high-dose vitamin D supplementation and those with missing follow-up data were also excluded. Serum 25(OH)D concentrations were measured using a mass spectrometry assay. The primary outcome was time to first adjudicated CHD event, defined as myocardial infarction, angina, cardiac arrest, or CHD death.
A total of 6,436 participants were included. At baseline, the mean age was 62 years, and 53% of participants were women. The mean (standard deviation) serum 25(OH)D concentration was 25.5 ng/ml, and varied substantially by race/ethnicity. Participants with lower serum 25(OH)D concentrations were less likely to be white, were more likely to smoke or have diabetes or chronic kidney disease, and were characterized by larger body mass, higher serum parathyroid hormone concentration, and lower physical activity levels. During a median follow-up of 8.5 years, 361 participants had an incident CHD event (7.38 events per 1,000 person-years). Associations of 25(OH)D with CHD differed by race/ethnicity (p for interaction < 0.05). 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% confidence interval [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).
The investigators concluded that 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.
These data suggest that serum 25(OH)D concentration is not associated with cardiovascular outcomes in all ethnic groups. Whether vitamin D supplementation reduced risk and varies by ethnicity remains to be determined. Hopefully the VITAL study will be able to address these questions.
Keywords: Ethnic Groups, Biological Markers, Cardiovascular Diseases, Hispanic Americans, Vitamin D, Mass Spectrometry
< Back to Listings