Hazard ratio 1.93 if 6 years earlier had vitamin D level of less than 20 nanograms/ml

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Low 25-Hydroxyvitamin D Predicts the Onset of Mobility Limitation and Disability in Community-Dwelling Older Adults: The Health ABC Study

Denise K. Houston1, Rebecca H. Neiberg2, Janet A. Tooze2, Dorothy B. Hausman3, Mary Ann Johnson3, Jane A. Cauley4, Doug C. Bauer5, M. Kyla Shea1, Gary G. Schwartz6, Jeff D. Williamson1, Tamara B. Harris7 and Stephen B Kritchevsky1 for the Health ABC Study
J Gerontol A Biol Sci Med Sci (2012); doi: 10.1093/gerona/gls136
1 Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
2 Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina
3 Department of Foods & Nutrition, University of Georgia, Athens
4 Department of Epidemiology, University of Pittsburgh, Pennsylvania
5 Department of Medicine, University of California, San Francisco
6 Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
7 Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland
Address correspondence to Denise Houston, PhD, Sticht Center on Aging, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1207. Email: dhouston at wakehealth.edu
Received November 22, 2011; Accepted April 13, 2012; First published online: May 9, 2012

Background. Although low 25-hydroxyvitamin D (25(OH)D) is prevalent among older adults and is associated with poor physical function, longitudinal studies examining vitamin D status and physical function are lacking. We examined the association between 25(OH)D, parathyroid hormone (PTH), and the onset of mobility limitation and disability over 6 years of follow-up in community-dwelling, initially well-functioning older adults participating in the Health, Aging and Body Composition study (n = 2,099).

Methods. Serum 25(OH)D and PTH were measured at the 12-month follow-up visit (1998–1999). Mobility limitation and disability (any/severe difficulty walking 1/4 mile or climbing 10 steps) was assessed semiannually over 6 years of follow-up. The association between 25(OH)D, PTH, and mobility limitation and disability was examined using Cox proportional hazard regression models adjusted for demographics, season, behavioral characteristics, and chronic conditions.

Results. At baseline, 28.9% of the participants had 25(OH)D <50 nmol/L and 36.1% had 25(OH)D of 50 to <75 nmol/L. Participants with 25(OH)D <50 and 50 to <75 nmol/L were at greater risk of developing mobility limitation (HR (95% CI): 1.29 (1.04–1.61) and 1.27 (1.05–1.53), respectively) and mobility disability (HR (95% CI): 1.93 (1.32–2.81) and 1.30 (0.92–1.83), respectively) over 6 years of follow-up compared with participants with 25(OH)D ?75 nmol/L. Elevated PTH, however, was not significantly associated with developing mobility limitation or disability.

Conclusions. Low 25(OH)D was associated with an increased risk of mobility limitation and disability in community-dwelling, initially well-functioning black and white older adults. Prevention or treatment of low 25(OH)D may provide a pathway for reducing the burden of mobility disability in older adults.
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See also Vitamin D Life

• Overview Seniors and Vitamin D
• Items in category Seniors and Vitamin D 341 items
• Seniors with less than 12 ng of vitamin D were not stable – March 2012
• Loss of muscle strength –sarcopenia – one of the suspects is vitamin D – Aug 2012
• Fraser Health in Canada is giving 20000 IU vitamin D weekly to reduce falls – Nov 2011
• Overview Falling, Fractures and Vitamin D
• Senior women more physically able if vitamin D higher than 30 ng – Sept 2011
• Seniors with more than 30ng of vitamin D walked better – May 2011
• Seniors with more than 20 ng of vitamin D were 14 percent stronger – May 2011
• Seniors who increased vitamin D got more physical exercise – Feb 2011
• Seniors low on vitamin D walk slower – April 2011
• Vitamin D improves muscle strength if deficient – meta-analysis - Oct 2010