Outdoor Air Pollution and Depression in Canada: A Population-Based Cross-Sectional Study from 2011 to 2016.

To assess whether exposure to increased levels of outdoor air pollution is associated with psychological depression, six annual iterations of the Canadian Community Health Survey (n ≈ 127,050) were used to estimate the prevalence of a major depressive episode (2011-2014) or severity of depressive symptoms (2015-2016). Survey data were linked with outdoor air pollution data obtained from the Canadian Urban Environmental Health Research Consortium, with outdoor air pollution represented by fine particulate matter ≤2.5 micrometers (µm) in diameter (PM2.5), ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2). Log-binomial models were used to estimate the association between outdoor air pollution and depression, and included adjustment for age, sex, marital status, income, education, employment status, urban versus rural households, cigarette smoking, and chronic illness. No evidence of associations for either depression outcomes were found. Given the generally low levels of outdoor air pollution in Canada, these findings should be generalized with caution. It is possible that a meaningful association with major depression may be observed in regions of the world where the levels of outdoor air pollution are greater, or during high pollution events over brief time intervals. Future research is needed to replicate these findings and to further investigate these associations in other regions and populations.

The Association of Active Living Environments and Mental Health: A Canadian Epidemiological Analysis.

Environments that promote use of active transport (walking, biking, and public transport use) are known as "active living environments" (ALE). Using a Canadian national sample, our aim was to determine if ALEs were associated with mental health outcomes, including depressive symptoms, and mood and anxiety disorders. Data from the Canadian Community Health Survey from 2015-2016 was used for demographic characteristics and mental health outcomes (n ≈ 110,000). This data was linked to datasets from the Canadian Urban Environmental Health Research Consortium, reporting ALE and social and material deprivation. Depressive symptoms were evaluated using standard dichotomized scores of 5+ (mild) and 10+ (moderate/severe) from the Patient Health Questionnaire-9. Self-reported diagnosed mood and anxiety disorders were also included. Logistic regression was used to determine the association of mental health outcomes with four classes of ALE. The analysis included adjustments for social and material deprivation, age, sex, chronic conditions, marital status, education, employment, income, BMI, and immigrant status. No association between any mental health outcome and ALE were observed. While the benefits of ALE to physical health are known, these results do not support the hypothesis that more favorable ALE and increased use of active transport is associated with better mental health outcomes.

Electronic cigarette use and mental health: A Canadian population-based study.

BACKGROUND: To examine the association between electronic cigarette (e-cigarette) use and adverse mental health status. METHODS: A cross-sectional analysis was conducted using data from the 2015 and 2016 Canadian Community Health Survey (n = 53,050). Sampling weights and associated bootstrap procedures were used to account for survey design effects. Multivariable logistic regression was employed to examine the association between e-cigarette use and the following mental health outcomes: depressive symptom ratings (using the Patient Health Questionnaire 9), self-reported professionally diagnosed mood and anxiety disorders, perceived mental health, suicidal thoughts/attempts, and binge drinking. RESULTS: The overall prevalence of past 30-day e-cigarette use was 2.9% (95% CI: 2.6-3.1). 11.5% (95% CI: 10.4-12.7) of smokers reported also using e-cigarettes. Dual users had the highest prevalence of adverse mental health status. The association between e-cigarette use and mental health was found to be modified by smoking status and sex in most of the logistic models. E-cigarettes had less than multiplicative effects among smokers. Female e-cigarette users tended to have higher odds of adverse mental health than male users. Overall, in the multivariable modeling, e-cigarette use was consistently associated with poor mental health among non-smokers and women, a finding that persisted after adjustment for additional covariates. CONCLUSIONS: These results indicate that e-cigarette use is associated with adverse mental health status, particularly among the non-smoking general population and women. LIMITATIONS: The study relied on respondent self-report, and the cross-sectional nature of the study does not allow us to clarify the direction of this association.