Patten SB, et al. – The intent of this analysis was to establish a link between secondhand smoke exposure and major depressive episode (MDE). With the aid of the findings, the public health measures directed towards reducing secondhand smoke exposure gained additional support. A causal connection between secondhand smoke exposure and MDEs could not be affirmed owing to the cross–sectional nature of the data. In order to establish temporal sequencing, advanced research was necessitated.

Methods

• Data was yielded from a series of 10 population surveys carried out in Canada between 2003 and 2013.
• The surveys targeted the Canadian household population, with the inclusion of a brief structured interview for past year major depressive episode (MDE) and included items examining secondhand smoke exposure.
• The two-stage individual-level random-effects meta-regression synthesized results from these surveys.

Results

• Approximately 20% of non-smokers reported considerable exposure to secondhand smoke, over the study interval.
• The pooled annual prevalence of MDE was 6.1% (95% CI 5.3-6.9) compared to 4.0% (95% CI 3.7-4.3) in non-smokers without secondhand smoke exposure, in this group.
• The crude odds ratio was disclosed to be 1.5 (95% CI 1.4-1.7).
• With adjustment for a set of potential confounding variables, the odds ratio remained unchanged, 1.4 (95% CI 1.2 - 1.6).