Air Pollution and Symptoms of Depression in Elderly Adults

Background: Although the effect of air pollution on various diseases has been extensively investigated; few studies have examined its effect on depression. Objectives: We investigated the effect of air pollution on symptoms of depression in an elderly population. Methods: We enrolled 537 participants in the study who regularly visited a community center for the elderly located in Seoul, Korea. The Korean version of the Geriatric Depression Scale-Short Form (SGDS-K) was used to evaluate depressive symptomatology during a 3-year follow-up study. We associated ambient air pollutants with SGDS-K results using generalized estimating equations (GEE). We also conducted a factor analysis with items on the SGDS-K to determine which symptoms were associated with air pollution. Results: SGDS-K scores were positively associated with interquartile range (IQR) increases in the 3-day moving average concentration of particulate matter with an aerodynamic diameter ≤ 10 µm (PM₁₀) [17.0% increase in SGDS-K score, 95% confidence interval (CI): 4.9%, 30.5%], the 0-7 day moving average of nitrogen dioxide [NO₂; 32.8% (95% CI: 12.6%, 56.6%)], and the 3-day moving average of ozone [O₃; 43.7% (95% CI: 11.5%, 85.2%)]. For these three pollutants, factor analysis showed that air pollution was more strongly associated with emotional symptoms such as feeling happy and satisfied than with somatic or affective symptoms. Conclusions: Our study suggests that increases in PM₁₀, NO₂, and O₃ may increase depressive symptoms among the elderly. Of the symptoms evaluated, ambient air pollution was most strongly associated with emotional symptoms.