[BACKGROUNDS] Walking speed is a simple assessment tool to measure the physical performance in older adults. Previous epidemiology studies suggest that phthalate exposure may contribute to cognitive deficits, neurobehavioral disorders and decreased muscle strength, which may all be associated with the decreased in physical performance.
[OBJECTIVES] We investigated the associations between urinary phthalate metabolites and walking speed in Korean elderly population.
[METHODS] We analyzed 1,180 older adults (≥ 60 years of age) recruited in Korean urban and rural areas (Seoul and Asan) between 2012 and 2014. Laboratory tests and physical examinations were repeatedly conducted during the follow up visit (visits range from 1 to 3). Phthalate exposure was estimated using the measures of three phthalate metabolites in urine: mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MnBP). Walking speed (m/s) was computed as walked distance (2.5 m) divided by measured time to walk (in seconds). The associations between urinary phthalate metabolites and walking speed were evaluated using linear mixed models adjusted for potential confounders.
[RESULTS] The geometric means of urinary concentrations of MEHHP, MEOHP, and MnBP were 21.11 (95% confidence interval (CI): 20.02-22.25) μg/L, 15.45 (95% CI: 14.68-16.27) μg/L, and 28.45 (95% CI: 27.23-29.72) μg/L, respectively. Urinary MEHHP concentration was dose-dependently associated with decrease in walking speed (p-trend=0.009). The highest (vs. lowest) quartiles of MEHHP and MEOHP were associated with a 0.05 (95% CI: 0.02-0.08) and 0.03 (95% CI: 0.00-0.06) m/s reduction in walking speed.
[CONCLUSIONS] Phthalate exposures, estimated by urinary phthalate metabolites, were associated with slower gait speed.