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Serum 25-Hydroxyvitamin D and Physical Function in Older Adults: The Cardiovascular Health Study All Stars

Authors


  • Portions of this work were presented in abstract form at the Gerontological Society of America Annual Meeting, Atlanta, Georgia, November 21, 2009, and the American Geriatrics Society Annual Meeting, Orlando, Florida, May 15, 2010.

Address correspondence to Denise K. Houston, Section on Gerontology and Geriatric Medicine, Department of Internal Medicine, Sticht Center on Aging, Wake Forest School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157. E-mail: dhouston@wakehealth.edu

Abstract

Objectives

To examine the association between 25-hydroxyvitamin D (25(OH)D) and physical function in adults of advanced age.

Design

Cross-sectional and longitudinal analysis of physical function over 3 years of follow-up in the Cardiovascular Health Study All Stars.

Setting

Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.

Participants

Community-dwelling adults aged 77 to 100 (N = 988).

Measurements

Serum 25-hydroxyvitamin D 25(OH)D), Short Physical Performance Battery (SPPB), and grip and knee extensor strength assessed at baseline. Mobility disability (difficulty walking half a mile or up 10 steps) and activities of daily living (ADLs) disability were assessed at baseline and every 6 months over 3 years of follow-up.

Results

Almost one-third (30.8%) of participants were deficient in 25(OH)D (<20 ng/mL). SPPB scores were lower in those with deficient 25(OH)D (mean (standard error) 6.53 (0.24)) than in those with sufficient 25(OH)D (≥30 ng/mL) (7.15 (0.25)) after adjusting for sociodemographic characteristics, season, health behaviors, and chronic conditions (P = .006). Grip strength adjusted for body size was also lower in those with deficient 25(OH)D than in those with sufficient 25(OH)D (24.7 (0.6) kg vs 26.0 (0.6) kg, P = .02). Participants with deficient 25(OH)D were more likely to have prevalent mobility (OR = 1.44, 95% confidence interval (CI)) = 0.96–2.14) and ADL disability (OR = 1.51, 95% CI = 1.01–2.25) at baseline than those with sufficient 25(OH)D. Furthermore, participants with deficient 25(OH)D were at greater risk of incident mobility disability over 3 years of follow-up (hazard ratio = 1.56, 95% CI = 1.06–2.30).

Conclusion

Vitamin D deficiency was common and was associated with poorer physical performance, lower muscle strength, and prevalent mobility and ADL disability in community-dwelling older adults. Moreover, vitamin D deficiency predicted incident mobility disability.

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