Temperature extremes and human health in Cyprus: Investigating the impact of heat and cold waves

In Mediterranean countries like Cyprus, extreme temperatures and especially heatwaves during summer months are increasingly common, leading to heightened bio-climatic stress. While coldwaves are less frequent and understudied in this region, they still pose significant health risks. This study utilizes temperature data from ERA5-Land in conjunction with mortality and hospitalization data from Cyprus. Employing statistical machine learning methods such as Distributed Lag Models (DLMs) and Generalized Additive Models (GAMs), mortality and hospitalization risks for major health concerns in Cyprus, along with attributable deaths and hospital admissions associated with temperature fluctuations and extreme events over two seasons, were estimated. This study also examines temperature trends over the past four decades in Cyprus, noting a significant increase in both maximum and minimum temperatures as well as an increase in extreme high-temperature days and a decrease in extreme low-temperature days. For mortality, elevated risks were identified at very high temperatures, peaking at shorter lags with up to a 7.5% above-average risk, which further increased to 14.3% during heatwave events in the warm season. Conversely, mortality risks at very low temperatures during the cold season reached 4.2% particularly for longer lag days. Hospitalization risks were notably higher during periods of cold temperatures. Importantly, our findings confirm that cold-related mortality exceeds heat-related mortality in absolute terms. However, during heatwave days, the rate of increase in attributable deaths is five times higher compared to typical days in the warm season, whereas for cold days it is about twice as high as on non-cold days.