(Un)Healthy in the city: Adverse health effects of traffic-related noise and air pollution

We investigated the adverse health effects of urbanity, traffic-related noise and air pollution. We used harmonized data from multiple European cohort studies: LifeLines, HUNT, FINRISK, EPIC-Oxford and KORA. Based on our studies, we concluded that the living environment may be associated with adverse health effects. Urban inhabitants had a decreased lung function, and more anxiety and depression, while metabolic syndrome was more prevalent in rural inhabitants. We also found a relation between road traffic noise and increased heart rate, but relations between noise and blood pressure differed per cohort study. Additionally, road traffic noise was not associated with prevalence of common somatic symptoms, such as headache, stomachache, and chest pain, but we did find a relation between noise annoyance and an increase in somatic symptoms. The results for the association between air pollution and depression were inconsistent.
Our findings also illustrate that heterogeneity between cohort studies can be challenging for multi-cohort research. The main advantages of using multiple cohort studies were the very large sample sizes, broad exposure ranges, and the ability to make comparisons across cohorts. In our study populations, exposure to traffic-related noise and air pollution was not consistently associated with our study outcomes. These findings are meaningful because they show us to be cautious with interpreting results from a single cohort study. The use of data from multiple cohort studies provides excellent opportunities for studying harmful environmental exposures. The scientific community should invest in the sharing and harmonization of their cohort data, supporting research on large geographical scales.