Geographic Variation in Mentally Unhealthy Days: Air Pollution and Altitude Perspectives.

Abstract

Mental health incorporates our emotional, psychological, and social well-being and it is critical at each phase of life, from youth and preadulthood through adulthood. We assessed the association between mentally unhealthy days (MUDs), air pollutant concentrations, and altitude on the basis of cross-county studies. Data on poor mental health days for the United States were based on health-related telephone surveys conducted by the Behavioral Risk Factor Surveillance System (BRFSS). Average annual regional air pollution data were obtained from Center for Disease Control and Prevention (CDC) WONDER Environmental data, and altitude data were collected from the U.S. Geological Survey (USGS). In the data set (across 2589 U.S. counties for 2011), even after accounting for potential confounding variables and multicollinearity, a significant association between altitude, air pollution, and poor mental health days was found, explaining that poor mental health days increase with increasing air pollution concentrations and with decreasing altitude (R2 = 0.663, p < 0.001). Controlling for socioeconomic (e.g., education and employment) and social (including social relationship and crime) factors did not change these findings. In this study, we found that counties with lower air pollution and higher altitude had significantly lower average number of MUDs reported within the past 30 days. This association has not been reported before in the literature. These findings suggest a need for further investigation into the extent that air quality and altitude may serve as significant factors for mental health and have major implications in our understanding of the etiology of mental health by medical professionals.