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22-08-2011 | Bone health | Article

Vitamin D insufficiency more prevalent in African Americans than Whites

Abstract

Free abstract

MedWire News: Older African Americans suffer from vitamin D insufficiency to a greater extent than older whites, according to recent findings.

Vitamin D insufficiency has been found to cause reduced bone strength and other age-related chronic conditions. The ability to synthesize vitamin D through the skin through exposure to ultraviolet light decreases with age.

In general, African Americans cannot synthesize vitamin D as easily as whites, and therefore often have vitamin D insufficiency for this and other reasons, but previously there had been no studies on what exactly determines vitamin D insufficiency in older whites and African Americans.

M Kyla Shea (Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA) and colleagues enrolled 2581 participants from the larger Health, Aging, and Body Composition Study population - well-functioning, community-dwelling adults between age 70 and 79 years. Of this subgroup, 62% were white and 38% were African American. The 25-hydroxyvitamin D (25[OH]D) levels were assessed through blood samples, and at a Year 2 clinic visit enrollees were surveyed about their diet over the past year, vitamin D supplement and multivitamin use, level of weekly physical activity, and lifestyle characteristics (eg, alcohol use). Body weight and height were also measured.

Overall, the investigators found lower serum 25(OH)D levels in African Americans than in whites (21.0 ± 10.4 vs 29.2 ± 10.9 ng/ml), as reported in the Journal of the American Geriatrics Society. About 54% of the African American enrollees had 25(OH)D levels of 20 ng/ml or less versus only 18% of the white enrollees. Whites were more likely to be taking vitamin D supplements or multivitamins and had a higher calcium intake.

In both and African Americans, obesity and female gender increased the odds of having a vitamin D insufficiency. Other risk factors for insufficiency were winter season, low dietary vitamin D intake, and type 2 diabetes in whites; and vitamin D supplement use in African Americans.

The investigators conclude that the information obtained from this study, plus the knowledge of other characteristics, "may provide additional pertinent information to identify older adults who are at risk for vitamin D insufficiency and, thus, for whom 25(OH)D screening and vitamin D supplementation might be appropriate."

MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Stephanie Leveene

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