Physical activity, indoor air pollution, and cognitive function among older-adults in India: Evidence of gendered...

Cognitive health in later life is shaped by both individual behaviours and the social and environmental conditions in which ageing occurs. Guided by the Stress Process Model, this study conceptualises indoor air pollution as a chronic environmental stressor that may constrain the cognitive benefits of health-promoting behaviours such as physical activity in later life. Using nationally representative data from the Longitudinal Ageing Study in India (LASI Wave 1), we examine the independent and joint associations of physical activity and indoor air pollution with cognitive function among 31,902 community-dwelling adults aged 60 years and older, with particular attention to gender differences. Cognitive function was assessed using a composite measure across multiple cognitive domains. Indoor air pollution exposure was defined using information on cooking fuel type, stove technology, cooking location, and ventilation. Physical activity was measured as self-reported engagement in moderate or vigorous activity or yoga-based practices. Multilevel linear regression analyses showed that physical activity was consistently associated with better cognitive performance, whereas exposure to indoor air pollution was associated with poorer cognitive outcomes. Although no overall interaction was observed in the full sample, but a significant gender-specific patterns emerged. Among women, exposure to indoor air pollution substantially reduced the cognitive benefits associated with physical activity, a pattern not observed among men. These findings highlight indoor air pollution as a gendered environmental constraint on healthy cognitive ageing and suggest that behavioural interventions alone may be insufficient in polluted household environments, particularly in low- and middle-income countries such as India.