Background and aimClimate change has far reaching consequences on all aspects of life, including health. Cardiovascular diseases (CVDs), the global leading cause of death, have also been found to be climate sensitive, mainly to temperature. However, the associations between CVDs and temperature are region-specific with relatively few studies focusing on low and middle-income countries. This study explores this association in Puducherry, a coastal district in the Eastern part India.Methods We analyzed the association between apparent temperature (Tapp) and in-hospital CVD mortalities in Puducherry between 2010 and 2020 using a binomial regression model. We used a distributed lag non-linear model to capture the delayed and non-linear trends and identify the optimal temperature range for Puducherry. The results are expressed as the fraction of CVD mortalities attributable to non-optimal temperatures. We also performed stratified analysis to explore the associations between Tapp and age and sex combined and different types of CVDs.Results We found that the optimal temperature range for Puducherry is between 33⁰C and 35⁰C with respect to CVDs. Temperatures both above and below the optimal temperature range were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Up to 20% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to cold (11.2%) than heat (9.1%). We also found that males above 60 years of age were more vulnerable to colder temperatures, while females above 60 years were more vulnerable to heat. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature.Conclusions We found the optimal temperature range for Puducherry to be higher than that previously reported for India as a whole, with a relatively high burden attributable to ‘cold’ temperatures, despite being an inherently hot region. Our study also identified the age and gender differences in temperature attributable CVD mortalities, which can be socio-cultural. Further studies from India could identify the regional associations and enhance the development of region and context specific climate-health action plans.
