The Journals of Gerontology Series A: Biological Sciences and Medical Sciences Advance Access published online on October 12, 2009
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, doi:10.1093/gerona/glp150
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© Published by Oxford University Press on behalf of The Gerontological Society of America 2009.
Joint Association of Obesity and Metabolic Syndrome With Incident Mobility Limitation in Older Men and Women—Results From the Health, Aging, and Body Composition Study
1 Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, Baltimore, Maryland
2 Living Conditions, Health and Wellbeing Unit, Division of Welfare and Health Policies, Helsinki, Finland
3 Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland
4 Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore
5 Sticht Center on Aging, Wake Forest University School of Medicine, Winston-Salem, North Carolina
6 Division of General Internal Medicine, University of California, San Francisco
7 Department of Foods and Nutrition, University of Georgia, Athens
8 Department of Epidemiology, University of Pittsburgh, Pennsylvania
9 Health Science Center, University of Tennessee, Memphis
10 Department of Health Sciences, VU University Amsterdam
11 EMGO Institute, VU University Medical Center, The Netherlands
Address correspondence to Sari Stenholm, PhD, Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, Harbor Hospital, 5th Floor, 3001 South Hanover Street, Baltimore, MD 21225. Email: stenholmsm{at}mail.nih.gov
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Abstract |
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Background: Although both obesity and the metabolic syndrome (MetS) are known risk factors for decline in physical function, the joint association of obesity and metabolic alterations with risk of incident mobility limitation is unknown.
Methods: Data are from 2,984 women and men aged 70–79 years participating in the Health, Aging, and Body Composition Study without mobility limitation at baseline. Obesity was defined as body mass index greater than or equal to 30 kg/m2 and the MetS as meeting greater than or equal to 3 of the ATP III criteria. Mobility limitation was defined as any difficulty walking one-quarter mile or climbing 10 steps during two consecutive semiannual assessments for more than 6.5 years.
Results: Incidence of mobility limitation was 55% in women and 44% in men. In women, adjusted risk of developing mobility limitation was progressively greater in nonobese participants with the MetS (hazard ratio [HR] = 1.49, 95% confidence interval [CI] = 1.24–1.80), obese participants without the MetS (HR = 1.95, 95% CI = 1.51–2.53), and obese participants with the MetS (HR = 2.16, 95% CI = 1.78–2.63) relative to the nonobese without the MetS. In men, the corresponding adjusted HRs (95% CI) were 1.07 (0.87–1.32), 1.64 (1.19–2.25), and 1.41 (1.12–1.78). Elevated inflammatory markers partly explained the association between obesity, the MetS, and mobility limitation, particularly in nonobese and obese participants with the MetS.
Conclusions: Obesity itself, independent of its metabolic consequences, is a risk factor for mobility limitation among obese older adults. In addition, having the MetS increases the risk of functional decline in older nonobese women but not in men.
Keywords Obesity; Metabolic syndrome; Mobility limitation; Inflammation; Older people
Received: July 27, 2009; Accepted: September 15, 2009