Environmental exposure assessment in the German National Cohort (NAKO)

BACKGROUND: The environment plays a major role in human health and wellbeing. Air pollution, non-optimal temperatures, noise and lack of greenspace have been identified as the main external drivers, but their interplay is not well understood. Moreover, negative impacts are expected to increase in the coming decades due to population growth and climate change, especially in urban areas. Therefore, we aimed to assess the exposure to multiple environmental indicators and compare the spatial variation across NAKO participants to lay the foundation for subsequent health analyses. METHODS: We collected German-wide data from different sources for the following environmental indicators: short- and long-term air pollution (particulate matter, nitrogen dioxide, ozone), short- and long-term meteorology (air temperature, relative humidity), noise and greenness. All exposures were assigned to the NAKO participants based on their baseline residential addresses. RESULTS: The NAKO study regions ranged from highly urbanized areas (Berlin, Hamburg) with up to 4,123 inhabitants/km(2) to rural regions (Neubrandenburg) with 732 inhabitants/km(2). This large variation is reflected in the individual environmental exposures. PM2.5 and NO2 levels ranged from 7.7-16.2 and 4.2-32.6 µg/m(3), respectively. Annual mean temperature for 2017 ranged between 8.1-11.7 °C. Noise data were available only for 22% of participants, of which 42% fell into the lowest and 1.9% into the highest category of Lden 55-59 and Lden >75 dB(A), respectively. Greenness also showed considerable contrasts (Normalized Difference Vegetation Index between 0.09-0.82). CONCLUSIONS: An extensive population-based data set with high-quality environmental indicators is available for the first time across Germany. Expanding the database by adding innovative indicators (e.g. light pollution, walkability) as well as socioeconomic factors (e.g. unemployment rate, deprivation) will further increase its impact on science and public health.