Effects of Climate Change on Seasonal Morbidity and Mortality of Respiratory Diseases in Germany

Daily weather affects human health in several ways and not only concerning climate change. In a previous study it was shown for Germany, that the occurrence of ischemic heart diseases is strongly linked with the thermal environment. In particular, the mortality due to ischemic heart diseases increases with higher temperatures and during heat waves. For the morbidity, however, no significant relationship to the thermal environment could be found. Besides ischemic heart diseases, respiratory diseases like asthma, bronchitis, and chronic obstructive pulmonary disease (COPD) are globally immense heath factors. In this study, we focus on the occurrence of respiratory diseases in Germany and possible effects of daily weather, climate, and climate change.

Therefore, a systematic literature review on this subject is conducted in the first step. In databases like PubMed and Science Direct, about 300 publications relevant for this issue were selected. In many of these studies, a negative effect of heat waves and cold temperature on respiratory diseases is found as well as the negative impact of air pollution.

In the second step, a retrospective analysis studying the relationship between respiratory diseases and weather is assessed. For this, daily mortality and morbidity (hospitalization) data on a county level of Germany for the period 2001-2015 are used in combination with meteorological observations from the German Meteorological Service (DWD) network. Mortality due to chronic respiratory diseases increases at higher temperatures and shows a stronger reaction to heat waves (+ 18 % excess-mortality) than ischemic heart diseases (10 % excess-mortality). Also hospitalizations due to respiratory diseases rise during hot days with the exception of asthma diagnosis, which shows no relationship with temperature. For daily mean temperatures below 17 °C, the risk of hospitalization increases as well, while mortality shows only a slight cold effect at temperatures below approximately 5 °C. Generalized Additive Models will be used to identify further significant meteorological parameters like Perceived Temperature, wind speed, and vapor pressure, which may have a significant influence on the occurrence of respiratory diseases.

In the last step, the change of specific parameters and weather patterns in the context of climate change is assessed using regional climate model simulations from the CORDEX project. Two different RCP scenarios (4.5 and 8.5) are selected to display the possible range of future effects. Several approaches based on single parameters, simple (humidex) and complex thermal indices like Perceived Temperature will be applied. This will allow us to estimate potential changes in the occurrence of respiratory diseases due to climatic changes for different periods in the future.