Seasonal and spatial considerations in assessing home environment characteristics, indoor dust microbiota and frailty

Seasonal variation and indoor environmental factors play important roles in shaping frailty risk among old adults. A recent study conducted by Yin et al. (Association between home environment characteristics, indoor dust microbiota and frailty among community-dwelling older adult couples. Age Ageing 2025;54:afaf321.) provided new evidences for the relationships between home conditions and indoor dust microbiota and frailty in older couples. However, this commentary highlights two key methodological challenges that may affect the interpretation of the findings of the study. First is seasonal confounding, given the seasonal variation of wet-bulb globe temperature (WBGT), particulate levels and indoor microbiota; and the limited temporal and spatial representativeness of single-time environmental and microbiological measurements, which may reduce the accuracy and interpretability of the results. Addressing these issues can promote causal inference and generalizability of the relationship between environmental factors and frailty among older adults. Furthermore, incorporating measurements of fine airborne particulate matter in future studies is recommended to better elucidate the role of indoor air quality in the frailty development pathway.