The impact of air temperature on mortality in İstanbul

Climate change negatively impacts İstanbul as a Mediterranean city. The observed trends of air temperature over the last decades shows an overall increase in air temperature and extreme events. İstanbul is also at an increased risk of heat stress due to the effect of increasing urbanization. Reliable estimates of air temperature’s health impacts in İstanbul are needed to understand the relationship between city’s climate and health of its residents. This study examined the relationship between ambient temperatures and respiratory, cardiovascular, and total (non-accidental) mortality to reveal the health effects of ambient temperatures between 2007 and 2012 in İstanbul. A distributed lag non-linear model (DLNM) paired with a quasi-Poisson regression was employed to analyze the city-specific lag effects of temperature on mortality. The temperature–mortality associations were modeled using a period of up to 21 days (lag 0–20) to examine the delayed and non-linear effects of cold and hot temperatures after the day of exposure. The findings of this study showed that extreme cold temperatures have the highest relative risk for cardiovascular mortality and extreme hot temperatures have the highest relative risks on respiratory and total mortality. Extreme hot days (above 97.5th percentile) and extreme cold days (below 2.5th percentile) accounted for 1.9 (95% CI [CI], 0–7.5) and 9.0 (95% CI, 3.1–21.0) excess deaths for every 1000 cardiovascular deaths, respectively.