Association of body mass index with self-report and performance-based measures of balance and mobility.

ABSTRACT

BACKGROUND: The incidence of obesity is increasing in older adults, with associated worsening in the burden of disability. Little is known about the impact of body mass index (BMI) on self-report and performance-based balance and mobility measures in older adults. OBJECTIVE: The purposes of this study were (1) to examine the association of BMI with measures of balance and mobility and (2) to explore potential explanatory factors. DESIGN: This was a cross-sectional, observational study. METHODS: Older adults (mean age=77.6 years) who participated in an ongoing observational study (N=120) were classified as normal weight (BMI=18.5-24.9 kg/m(2)), overweight (BMI=25.0-29.9 kg/m(2)), moderately obese (BMI=30.0-34.9 kg/m(2)), or severely obese (BMI ≥ 35 kg/m(2)). Body mass index data were missing for one individual; thus, data for 119 participants were included in the analysis. Mobility and balance were assessed using self-report and performance-based measures and were compared among weight groups using analysis of variance and chi-square analysis for categorical data. Multiple linear regression analysis was used to examine the association among BMI, mobility, and balance after controlling for potential confounding variables. RESULTS: Compared with participants who were of normal weight or overweight, those with moderate or severe obesity were less likely to report their mobility as very good or excellent (52%, 55%, 39%, and 6%, respectively); however, there was no difference in self-report of balance among weight groups. Participants with severe obesity (n=17) had the lowest levels of mobility on the performance-based measures, followed by those who were moderately obese (n=31), overweight (n=42), and of normal weight (n=29). There were no differences on performance-based balance measures among weight groups. After controlling for age, sex, minority status, physical activity level, education level, and comorbid conditions, BMI still significantly contributed to mobility (ß=-.02, adjusted R(2)=.41). CONCLUSIONS: Although older adults with severe obesity were most impaired, those with less severe obesity also demonstrated significant decrements in mobility.