On the compound effect of humidity and temperature on mortality in the Eastern Mediterranean

The Mediterranean region has seen a rapid rise in the frequency, intensity, and duration of temperature extremes over the past two decades. These conditions have increased heat stress, posing serious threats to human health, particularly among vulnerable groups like the elderly. Investigating the effects of moist heat on mortality is crucial to understanding the broader impacts of climate change and improving response strategies.

This study focuses on Cyprus, a Mediterranean island, to examine the relationship between temperature, vapour pressure, and mortality. Meteorological data were obtained from the Copernicus European Regional Reanalysis (CERRA) at high spatial (5.5 km) and hourly temporal resolution, then aggregated across the five districts of Cyprus. Daily mortality data, including deaths from cardiovascular and respiratory diseases (ICD10: I00-I99 and J00-J99), were analyzed for the period 2004–2019. Distributed Lag Non-Linear Models (DLNMs), within the Generalized Additive Models (GAMs) framework, were applied to assess the lagged effects of temperature, vapour pressure, and relative humidity on mortality rates. The results highlight significant health risks for elderly individuals (65+), revealing a strong correlation between environmental factors and mortality in this age group. The combined impact of elevated temperatures and high vapour pressure significantly increases these risks, aligning with thermo-physiological findings. The study also compares both coastal and non-coastal cities, demonstrating the pronounced influence of humidity on health outcomes. These results highlight the importance of implementing targeted interventions and integrating aging populations into early warning systems to safeguard them from climate-related health risks.