Association between perceived neighborhood environment, sedentary behavior, walking, and moderate-to-vigorous physical activity and frailty: an isotemporal substitution model

IntroductionWith the rapid increases of older population and growing demand for longevity worldwide, frailty has become a major hurdle to sustaining healthy aging. As residential areas are the primary domains of mobility for older adults, the neighborhood environment is a crucial factor for their daily living and physical activity. This study aims to investigate whether replacing sedentary behavior with physical activity and having a supportive neighborhood environment are associated with frailty status in older adults.MethodsA cross-sectional analysis was conducted with 2,650 participants aged 70-84 years from the Korean Frailty and Aging Cohort Study (KFACS). The main explanatory variables included self-reported physical activity, sedentary behavior (SB), and perceived neighborhood environment. Frailty as the response variable was defined using the Fried frailty phenotype. Multinomial regression was performed to analyze the outcome. The Isotemporal Substitution Model (ISM) was applied to examine the effects of replacing sedentary behavior with physical activity.ResultsThe frailty status of participants was categorized as 45.3% robust, 47.3% pre-frail, and 7.6% frail. Accessibility factor was associated with a decreased risk of being pre-frail (odds ratio (OR): 0.750, 95% CI: 0.673-0.836) and frail (OR: 0.654, 95% CI: 0.541-0.789) compared to being robust. According to ISM, substituting 10 min of SB with any type of physical activity was associated with a reduced risk of pre-frailty [if 10 min of SB was replaced by 10 min of walking (OR: 0.972, CI: 0.960-0.985)] and frailty [if 10 min of SB was replaced by MVPA (OR: 0.877, CI: 0.836-0.921); or by walking (OR: 0.852, CI: 0.814-0.891)].ConclusionsReplacing SB with walking and improving neighborhood accessibility were significantly associated with reduced risk of being pre-frail or frail. These findings highlight the importance of considering these factors when designing age-friendly environments for older adults.