Lower levels of Vitamin D tied to the development of peripheral vascular disease

January 13, 2009

Racial differences in cardiovascular risk factors do not fully explain the higher prevalence of lower-extremity peripheral arterial disease (PAD) in black adults. This damage to the circulatory system of the legs leads to pain and swelling, great discomfort, poorly healing wounds, difficulty in walking and exercising, and a heightened risk of dangerous or painful blood clot development.
The researchers sought to determine whether any of this excess risk may be explained by vitamin D status, which has been widely documented to be lower in blacks than in whites. They designed a population-based cross-sectional study that included 2987 white and 866 black persons aged 40 or older who were followed from the 2001–2004.

The average (mean) Vitamin D level measured as 25-hydroxyvitamin D were significantly lower in black than in white adults (39.2 ± 1.0 and 63.7 ± 1.1 nmol/L, respectively). The higher the level of Vitamin D the lower the risk of suffering with PAD. Adjusted odds ratios for PAD decreased in a dose-dependent fashion with increasing quartiles (25% increments) of Vitamin D in white adults with a 47% decreased risk in the top quarter. In black adults, the association was nonlinear. The results suggested evidence of greater odds for PAD and a trend for lower odds for PAD at the lowest and highest concentrations of 25(OH)D respectively. After adjustment for racial differences in socioeconomic status and for traditional and novel risk factors, odds for PAD in black compared with white adults were reduced from 2.11 (95% CI: 1.55, 2.87) to 1.67 (1.11, 2.51). After additional adjustment for 25(OH)D, the odds were further reduced to 1.33 (0.84, 2.10). Racial differences in vitamin D status may explain nearly one-third of the excess risk of PAD in black compared with white adults. Additional research is needed to confirm these findings. The researchers were from the Welch Center for Prevention, Epidemiology, and Clinical Research and Johns Hopkins Bloomberg School of Public Health, Baltimore, and the Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, MD, and University of California, San Diego, CA. The study is published in the December 2008 issue of the American Journal of Clinical Nutrition, a journal of the American Society for Clinical Nutrition.