Association of Body Mass Index With Self-Report and Performance-Based Measures of Balance and Mobility

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/m2), moderately obese (BMI=30.0-34.9 kg/m2), or severely obese (BMI >= 35 kg/m2). 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 (beta=-.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.