Influences of Body Composition, Multimorbidity and Polypharmacy on Physical Mobility of Older Adults

Abstract

Background and Purpose: The prevalence of falls, and the resulting injuries and complications reflect a key concern in the older adult population. An increased risk of falls is highly correlated with decreases in physical mobility and related functions. The Timed Up-and-Go test (TUG) has an established reliability and validity in assessing physical function and the risk of falling in the older adult population. With age, a person typically has an increased number of health morbidities, which may be reflected in changing body composition and the number of medications associated with diseases. However, the influence of these factors on physical mobility in the older adult population has not been quantified. The purpose of this study was to investigate how common indicators of health, including body mass index (BMI), presence of multimorbidity and polypharmacy influence the TUG performance in the older adult population. Methods: A total of 222 individuals ≥ 65 years of age were recruited (68 men and 154 women, mean age = 75.1 yrs). Additional subjects (28 men and 54 women, mean age = 72.7 yrs) from previous research were included in the analysis of BMI on TUG performance with a total of 304 subjects (96 men and 208 women, mean age= 74.4 yrs). Height and weight were obtained in conjunction with a medical history survey. Subjects completed 3 trials of the TUG test at 3 and 9 m walking distances. Comparison was made between 3 participant groups according to their BMI (underweight: BMI 30 kg/m2). Multimorbidity was categorized into 2 groups (multimorbidity: ≥ 2 morbidities, non-multimorbidity: 0-1 morbidity). Polypharmacy was categorized into 2 groups (polypharmacy: ≥ 5 medications, non-polypharmacy: 0-4 medications). Non-parametric tests were run for all 3 variables (BMI, multimorbidity, and polypharmacy). Results: The underweight BMI group exhibited a trend of slower performance than normal weight BMI group for the 3 m (underweight = 8.8±5.3s, normal weight = 8.5±3.3s, p = 0.055) and the 9 m TUG distances (underweight = 17.3±8.9s, normal weight = 17.0±6.1s, p = 0.071). There was a trend toward the overweight BMI group having slower performance than the normal weight BMI group on the 9 m distance (normal weight = 17.0±6.1s, overweight = 18.0±5.5s, p = 0.069). The group with ≥ 2 morbidities had slower performance on the 3 m (multimorbidity = 9.2±3.9s, non-multimorbidity = 7.7±2.1s, p < 0.001) and 9 m TUG distances (multimorbidity = 18.3±6.8s, non-multimorbidity = 15.6±4.0s, p < 0.001). The polypharmacy group had slower performance on the 3 m (polypharmacy = 9.6±3.3s, non-polypharmacy = 8.3±3.4s, p = 0.001) and 9 m TUG distances (polypharmacy = 19.1 ± 5.9s, non-polypharmacy = 16.7±6.0s, p = 0.001). Discussion: Being underweight and overweight were shown to impact a person’s walking ability. We expected overweight individuals to have a slower performance on the TUG but underweight individuals did as well. This could be due to frail older adults having decreased…