Impact of Abdominal Obesity on Frailty Development: A Web-Based Survey Using a Smartphone Health App

Background/Objectives: Identifying adults with high frailty risk and intervening appropriately are critical issues for extending healthy life expectancy. This study examined whether abdominal obesity influences the progression to frailty among community-dwelling adults in Osaka Prefecture. Methods: Data were obtained from 2,962 individuals aged 30–79 years (62.7 ± 8.8 years) who responded to annual surveys via a health app in both 2023 and 2024, with available records on waist circumference. Frailty was assessed using the Kihon Checklist. Logistic regression analysis was conducted to identify predictors of frailty progression. Results: At baseline (2023), 23% of the participants had abdominal obesity and 18% were categorized as frailty. Among 2,431 participants initially without frailty, frailty incidence in the subsequent year was higher in those with abdominal obesity than those without (10.5% vs. 7.2%, p = 0.011). However, logistic regression analysis revealed that frailty awareness and exercise habits, not abdominal obesity, were significant predictors of frailty development in the following year. Conclusions: Although abdominal obesity was associated with frailty onset in crude analyses, its independent effect disappeared after adjustment. Knowledge of frailty and regular exercise appears to mitigate the risk, suggesting that lifestyle education and awareness campaigns may offset the impact of abdominal obesity on frailty development.