Association of 25-hydroxyvitamin D with incident coronary heart disease in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study

Abstract

Background: Low circulating 25-hydroxyvitamin D (25[OH]D) has been associated with increased risk of coronary heart disease (CHD), but whether this association differs by race is unclear.

Methods: We examined the association of 25[OH]D with incident CHD in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a prospective cohort study of black and white adults ≥45 years of age enrolled between 2003 and 2007 with follow-up through December 31, 2011. Using a case-cohort design, we measured 25[OH]D in 829 participants who developed incident CHD (cases) and in 813 participants without CHD randomly selected from the REGARDS cohort (comparison subcohort). Cox proportional hazards models were used to examine associations of 25[OH]D with incident CHD adjusting for established CHD risk factors in the study sample overall and stratified by race.

Results: In the fully adjusted model, lower quintiles of 25[OH]D were associated with a greater risk of incident CHD (25[OH]D > 33.6 ng/mL reference; 25[OH]D > 27.1-33.6 ng/mL, hazard ratio [HR] 2.79, 95% CI 1.64-4.76; 25[OH]D > 22.4-27.1 ng/mL, HR 2.77, 95% CI 1.57-4.89; 25[OH]D > 16.5-22.4 ng/mL, HR 5.52, 95% CI 3.21-9.50; 25[OH]D ≤ 16.5 ng/mL, HR 7.46, 95% CI 4.19-13.25). The results were similar when 25[OH]D was examined on a continuous scale (HR per 10-ng/mL decrement in 25[OH]D 2.04, 95% CI 1.65-2.52). The results did not statistically differ by race whether 25[OH]D was examined as a categorical or continuous variable (P_interaction > .10).

Conclusions: Lower plasma 25(OH)D concentrations were associated with higher risk of incident CHD. In contrast to prior studies, these associations did not differ by race.

Figure 1.

Association between race-specific quintiles of 25-hydroxyvitamin D and incident coronary heart disease in black (A) and white (B) REGARDS participants. This is a graphical representation of the estimates from the adjusted model, reported fully in Table 3. Hazard ratios were determined from a Cox proportional hazards model adjusted for age, sex, season of blood draw, systolic blood pressure, diastolic blood pressure, body mass index, income, current smoking, diabetes status, left ventricular hypertrophy, and medication use (statins, aspirin, angiotensin II receptor blockers, angiotensin converting enzyme inhibitors, spironolactone), estimated glomerular filtration rate, log-transformed urine albumin to creatinine ratio, log-transformed high-sensitivity C- reactive protein, intact parathyroid hormone, triglycerides, high-density lipoprotein-cholesterol, and total cholesterol.

Figure 1.

Association between race-specific quintiles of 25-hydroxyvitamin D and incident coronary heart disease in black (A) and white (B) REGARDS participants. This is a graphical representation of the estimates from the adjusted model, reported fully in Table 3. Hazard ratios were determined from a Cox proportional hazards model adjusted for age, sex, season of blood draw, systolic blood pressure, diastolic blood pressure, body mass index, income, current smoking, diabetes status, left ventricular hypertrophy, and medication use (statins, aspirin, angiotensin II receptor blockers, angiotensin converting enzyme inhibitors, spironolactone), estimated glomerular filtration rate, log-transformed urine albumin to creatinine ratio, log-transformed high-sensitivity C- reactive protein, intact parathyroid hormone, triglycerides, high-density lipoprotein-cholesterol, and total cholesterol.