Relationship between chronic exposure to ambient air pollution and mental health in Korean adult cancer survivors and the general population

Although a significant association between air pollution and mental health has been identified, few studies have addressed this relationship based on cancer diagnosis. This study investigated whether associations between long-term air pollution and mental health conditions differ based on whether the individual has been diagnosed with cancer. Nationally representative data were used and a total of 38,101 adults were included in the analyses. We assessed mental health factors such as perceived stress, depressive symptoms, and suicidal ideation, and analyzed the associations between these factors and individuals' annual average exposure to air pollutants, including particulate matter with an aerodynamic diameter ≤ 10 μm (PM ), nitrogen dioxide, sulfur dioxide, and carbon monoxide. Compared with the general population, PM exposure in cancer survivors predicted a higher risk of depressive symptoms (odds ratio [OR] =1.34; 95% confidence interval [CI] = 1.06-1.69) and suicidal ideation (OR = 1.29; 95% CI = 1.01-1.64). Notably, the statistically significant relationship between PM exposure and suicidal ideation in cancer survivors disappeared after further adjustment for depressive symptoms (p = 0.3103). This pattern was also observed in the result of propensity score-matched analysis for comparison between cancer survivors and the general population. This study provides the first evidence that cancer survivors with depressive symptoms may be more susceptible to suicidal ideation in the context of persistent PM exposure.