Air pollution and self-perceived stress and mood: A one-year panel study of healthy elderly persons

Abstract

Background and objectives: Previous studies have suggested that air pollution is associated with depression and anxiety symptoms. Here, we investigate the association between personal exposure to NO2 and perceived stress and mood in a panel of healthy elderly persons. Methods: In a one-year panel study, we included 20 healthy volunteers (10 male-female couples aged 58-76 years) with air pollution and health parameters measured every two months (120 observations). We measured personal exposure to NO2 in the previous 5 days, perceived stress using the Perceived Stress Scale (PSS) and positive and negative affect with the Positive and Negative Affect Schedule (PANAS). We used linear and Poisson mixed models to evaluate the associations between the health outcomes and NO2 adjusted for age, sex, temperature in the previous 5 days, sunlight in the previous day and physical activity (daily average number of steps on the previous week). Also, the interaction terms between NO2 and physical activity were tested. We report % changes for PSS scores and unit changes (beta) for positive and negative affect, and their 95% confidence intervals (CI), for changes in 10 mu g/m(3) of NO2. Results: After adjustment, an increase by 10 mu g/m(3) in NO2 concentrations was associated with a decrease of 1.3 points in the positive affect (95% CI -2.49 to - 0.17) and an increase of 0.11 points in the negative affect (95% CI 0.02 to 0.20). The association with positive affect was stronger when physical activity was below median value of 9,362 steps per day (beta = -2.68; CI: 4.87 to - 0.49); p-value for interaction was 0.08. No statistically significant associations were observed with perceived stress. Conclusion: Short-term exposure to air pollution may produce non-pathological alterations in mood in healthy elderly population.