Extreme heat events increase stroke risk among India’s older adults: evidence from longitudinal ageing study in India

Abstract The world is getting hotter and older at the same time, and stroke sits at the intersection of these two crises. These factors are predicted to increase in the future. However, epidemiological studies have focused on different countries; research in the Indian context remains limited. To address the gap, the association between stroke and extreme heat days has been investigated among India’s older adults. The association between extreme heat days, i.e. the average of the number of days exceeding the 90th percentile, and self-reported stroke prevalence was analyzed using generalized linear mixed models, with information from the Longitudinal Ageing Study in India. 14,594 individuals aged 45 years and above were involved in this research study. Stratified analysis was performed for gender, residence, education levels, and comorbidities, including diabetes and hypertension. The extreme heat days over the last 12 years are positively associated with stroke. A one-standard-deviation increase in the frequency of extreme heat days was associated with 18% higher odds for stroke (AOR, 1.18; 95% CI, 1.02–1.38). In stratified analysis females (AOR 1.31, 95% CI 1.04–1.66), urban residents (AOR 1.53, 95% CI 1.19–1.97), individuals with no education (AOR 1.31, 95% CI 1.05–1.64), individuals with hypertension (AOR 1.33, 95% CI 1.08–1.63) and diabetes (AOR 1.40, 95% CI 1.08–1.82) had elevated odds for stroke associated with long term exposure to extreme heat days. Our research study focused on the first evidence that long-term exposure to extreme heat days was positively associated with stroke prevalence, leading to fatal cardiovascular disease, in older adults in India.