Vitamin D deficiency is associated with worse cognitive performance and lower bone density in older African Americans.
BACKGROUND
Vitamin D deficiency is common in older adults and is more prevalent among persons with darker pigmented skin. The detrimental effects of vitamin D deficiency on the bone are widely known; however, recent data suggest that vitamin D deficiency may contribute to other disorders, including low mood, cognitive impairment, and impaired mobility.


OBJECTIVE
The purpose of this study was to determine whether nonskeletal diseases such as depression, cognitive impairment, and physical disability, which have been associated with vitamin D deficiency, are more commonly seen in older African Americans.


METHODS
In a cross-sectional study of 60 older adults (30 African Americans and 30 European Americans), vitamin D status, cognitive performance, physical performance, and bone mineral density (BMD) were assessed. Differences between groups and differences between those with vitamin D deficiency and those with normal vitamin D levels were tested.


RESULTS
African Americans had a lower mean 25-hydroxyvitamin D level (17.98 ng/ml; SD, 6.9) compared to European Americans (25.20 ng/ml; SD, 7.0; p < .0001). Participants with vitamin D deficiency performed worse on a measure of cognitive performance, the Short Blessed Test (10.87 vs 6.31; p = .016); the Physical Performance Test (PPT) (27.00 vs 28.96; p = .039); and had lower BMD (0.823 vs 0.914; p = .005) and t scores (-1.29 vs -0.72; p = .008) of the hip. Among African Americans, vitamin D deficiency was associated with worse cognitive performance and lower BMD of the hip.


CONCLUSIONS
Vitamin D deficiency in older African Americans was associated with worse cognitive performance and lower BMD of the hip.
Wilkins
Consuelo H
CH
Department of Medicine, Division of Geriatrics and Nutritional Science, Alzheimer's Disease Research Center, Washington University School of Medicine, St Louis, Missouri 63108, USA. cwilkins@wustl.edu
Birge
Stanley J
SJ
Sheline
Yvette I
YI
Morris
John C
JC
D001741:Black or African American / Q000706:statistics & numerical data*; D000367:Age Factors; D000368:Aged; D015519:Bone Density; D016022:Case-Control Studies; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D009752:Nutritional Status; D010024:Osteoporosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology
D014807:Vitamin D; C104450:25-hydroxyvitamin D