OBESITY AND MUSCLE WEAKNESS AS RISK FACTORS FOR MOBILITY LIMITATION IN COMMUNITY-DWELLING OLDER JAPANESE WOMEN: A TWO-YEAR FOLLOW-UP INVESTIGATION

Objectives: To examine the combined association of obesity and low muscle strength with mobility limitation in older adults. Design, setting and participants: This two-year follow-up longitudinal study included pooled data from 283 older community-dwelling Japanese women without mobility limitations who were 65 to 87 years of age (mean age 72.2 +/- 5.0 years). Measurements: Muscle strength was measured by hand-grip strength (HGS). The participants were categorized by HGS (high muscle strength: HGS >= 19.6 kg, low muscle strength: HGS <19.6 kg) and body mass index (BMI) (obese: BMI <25 kg/m(2), normal weight: BMI <25 kg/m(2)). The main outcome was mobility limitation, assessed by a self-reported questionnaire (difficulty walking one-half mile or climbing 10 steps without resting). Multivariate logistic regression analysis was performed to determine the combined effect of HGS and BMI on mobility limitation, adjusting for age, exercise habits, medications, and knee pain. Results: During the follow-up period, 82 of 283 participants (29.0%) developed mobility limitation. The adjusted odds ratios (95% confidence interval) for the incidence of mobility limitation were 1.53 (0.86-2.73) and 2.05 (1.08-3.91) in the obese and low muscle strength groups, respectively. Obesity combined with low muscle strength exhibited a significant and strong association with mobility limitation (odds ratio: 3.88, 1.08-13.91) compared with participants with normal weight and high muscle strength. Conclusion: Among community-dwelling older Japanese women, obesity alone was not associated with the incidence of mobility limitation, but when combined with low muscle weakness, the risk of developing mobility limitation was 3.9-fold greater than for the reference group.