Serum 25-hydroxyvitamin D is associated with incident peripheral artery disease among white and black adults in the ARIC study cohort

Background and aims Low 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with peripheral artery disease (PAD). Prevalence of low 25(OH)D and PAD differ between whites and blacks. However, these associations have not been studied prospectively or in a population based cohort. We tested the hypothesis that low 25(OH)D is associated with greater risk of incident PAD in white and black adults. Methods 25(OH)D was measured in serum collected at ARIC visit 2 (1990–1992). We followed 11,789 ARIC participants free of PAD at visit 2 through 2011 for incident PAD events. 25(OH)D (ng/mL) was categorized as deficient (<20), insufficient (20 to <30) or sufficient (≥30). PAD was defined by an ankle brachial index (ABI) of <0.9 at ARIC visits 3 or 4 or a hospital diagnosis with an ICD-9 code indicating PAD during follow-up. Analysis used multivariable-adjusted Cox proportional hazards regressions. Results Over a mean follow-up of 17.1 years, 1250 incident PAD events were identified. 22% of whites and 61% of blacks were 25(OH)D deficient. After adjustment for demographic characteristics, the hazard ratio (95% CI) of PAD in participants with deficient versus sufficient 25(OH)D was 1.49 (1.26, 1.76). Inclusion of BMI, physical activity, and smoking status attenuated the association [1.25 (1.06, 1.48)]. The association between 25(OH)D and PAD was qualitatively stronger in blacks (p for interaction = 0.20). Conclusions Deficient 25(OH)D was associated with increased risk of PAD in black and white participants. Whether treatment of low vitamin D through supplementation or modest sunlight exposure prevents PAD is unknown.