Electric appliance usage measured by a sensor and frailty in Japan

Abstract Background The measurement of in-home activity for frailty is limited by poor adherence, recall bias in self-reported measurements, and difficulties with long-term tracking. Data on electrical appliance usage can estimate in-home activities and be measured every minute, objectively, and continuously for over a year with a single sensor. The aim of this study is to investigate whether long- or short-term electric appliance use is associated with frailty symptoms in older adults. Methods This is a cross-sectional study. The participants were recruited from two municipalities in Japan: one urban and one rural. Eligibility criteria included: (1) completion of measurement and provision of consent, (2) age 65 years or older, and (3) no missing data. The study used electric appliances and self-reported questionnaire data collected between February 2022 and February 2024 in Japan. Electric appliance data were collected using non-intrusive load-monitoring technology, which monitors usage regardless of appliance type. Usage times were monitored over one year, and mean daily usage (one unit: 3 h/day) per appliance was used as the exposure. Frailty symptom was defined using the “Kihon Checklist”, with a cutoff point of 6/7. Modified Poisson regression models were used to estimate the associations between appliance usage and frailty symptoms. In adjusted model, the covariates included age, sex, years of education, depressive symptoms, and municipality. Risk ratios (RR) and 95% confidence intervals (95% CI) were calculated. Results Of 71 participants, 12 (16.9%) had frailty symptoms. The mean age and standard deviations (SD) were 80.1 (SD: 7.3) for the participants with frailty symptoms and 78.2 (SD: 5.7) for the participants without frailty symptoms. In crude model, spring and winter air conditioner usage was significantly associated with frailty symptoms (RR [95% CI]: 2.85 [1.02–7.93] for spring; RR [95% CI]: 1.31 [1.06–1.61] for winter). After adjustment for covariates, winter air conditioner usage was significantly associated with frailty symptoms (RR [95% CI] 1.34, [1.03–1.72]). Other appliances (television, washing machines, microwave ovens, and rice cookers) and air conditioners in summer and autumn showed no significant association. Conclusions Monitoring winter electrical appliance usage may aid in detecting frailty symptoms in older adults.