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Zdero, Svetlana

University of British Columbia

Background: Emerging evidence suggests that long-term exposure to outdoor fine particulate matter (PM₂.₅) may increase the risk of major depressive disorder (MDD). However, few studies have explored this relationship in low- and middle-income countries, where individuals disproportionately experience higher disease burden from air pollution exposure and higher risk for poor mental health. This study aimed to characterize associations between ambient PM₂.₅ exposure and depressive symptoms within urban and rural communities in 21 high-, middle-, and low-income countries. Methods: This cross-sectional analysis used baseline data from the Prospective Urban Rural Epidemiology (PURE) cohort. Adults aged 35-70 completed the Short-Form Composite International Diagnostic Interview (CIDI-SF), where ⩾4 of 7 depressive symptoms was predictive of MDD. Participants were assigned community-level annual average PM₂.₅ estimates for the year before cohort entry. Multilevel logistic regression models estimated associations in each country, among urban and rural communities, and country-level odds ratios were pooled using random-effects meta-regression. Results: The analysis included 156,634 adults enrolled between 2001 and 2019, with complete data on relevant covariates. The prevalence of reporting ⩾4 symptoms of feeling sad, blue, or depressed for two weeks or longer in the past year was 13.3% in urban communities (from 0.7% in Bangladesh to 44.2% in Palestine), and 9.7% in rural communities (from 0.6% in Philippines to 32.3% in Zimbabwe). Annual average PM₂.₅ concentrations varied widely in urban areas, from 9.6 µg/m³ in Canada to 70.1 µg/m³ in Pakistan, with a similar range in rural areas. In adjusted models, the pooled association was moderately strong in rural populations (OR=1.60, 95% CI: 0.97-2.64 per average increase in 10 µg/m³ of ambient PM₂.₅ in a given country, 𝐼²=78.6%), and weaker in urban populations (OR=1.08, 95% CI: 0.69-1.70, 𝐼²=94.9%). Effect estimates were highly variable between countries, but statistically non-significant across the entire cohort. Conclusions: These findings suggest that the relationship between long-term ambient PM₂.₅ exposure and depressive symptoms is highly context-dependent, and further location-specific studies are warranted to address this heterogeneity. Given the well-documented health risks of ambient PM₂.₅, efforts to reduce air pollution levels could provide dual benefits for both physical and mental health.

Text

2025-04-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90823

Population and Public Health

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/