Long-term exposure to ambient air pollution, genetic susceptibility, and the incidence of bipolar disorder: A prospective cohort study

Dankang Li; Yudiyang Ma; Feipeng Cui; Yingping Yang; Run Liu; Linxi Tang; Jianing Wang; Yaohua Tian

doi:10.1016/j.psychres.2023.115396

Long-term exposure to ambient air pollution, genetic susceptibility, and the incidence of bipolar disorder: A prospective cohort study

Psychiatry Res. 2023 Sep:327:115396. doi: 10.1016/j.psychres.2023.115396. Epub 2023 Aug 3.

Authors

Dankang Li¹, Yudiyang Ma¹, Feipeng Cui¹, Yingping Yang¹, Run Liu¹, Linxi Tang¹, Jianing Wang¹, Yaohua Tian²

Affiliations

¹ Ministry of Education Key Laboratory of Environment and Health, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, No.13 Hangkong Road, Wuhan, 430030, China; Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, No.13 Hangkong Road, Wuhan, 430030, China.
² Ministry of Education Key Laboratory of Environment and Health, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, No.13 Hangkong Road, Wuhan, 430030, China; Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, No.13 Hangkong Road, Wuhan, 430030, China. Electronic address: yaohua_tian@hust.edu.cn.

PMID: 37549511
DOI: 10.1016/j.psychres.2023.115396

Abstract

There is mounting recent evidence showing that air pollution exposure may be related to the risk of mental health, yet the association between long-term exposure to air pollution and the risk of incident bipolar disorder (BD) remains unclear. Thus we aim to identify associations between air pollution and the incidence of BD in a prospective population-based cohort. In total, 482,726 participants who were free of BD from the UK Biobank were included in this prospective study. We applied time-varying Cox proportional hazards models, accounting for relevant confounders, and used annual-year moving averages of air pollution as time-varying exposures. The genetic risk for BD was categorized into three categories (low, intermediate, and high) according to the tertiles of polygenic risk score. During a median of 10.79-year follow-up, 923 incident BD events were recorded. Long-term exposures to PM_2.5, PM₁₀, NO₂, and NO_x were associated with increased BD risk. Estimated HRs (95% CIs) for each interquartile range increase in PM_2.5, PM₁₀, NO₂, and NO_x concentrations were 1.31 (1.18-1.45), 1.19 (1.09-1.31), 1.19 (1.08-1.30), and 1.16 (1.07-1.26), respectively. Associations were still observed and even stronger at pollutant concentrations lower than WHO air quality guideline. In subgroup analysis stratified by genetic risk, we observed consistent associations between all pollutants and BD risk in intermediate and high genetic risk groups, but not in low genetic risk group. For example, the HRs (95% CIs) for PM_2.5 were 1.00 (0.94-1.53), 1.30 (1.06-1.59), and 1.34 (1.16-1.54) in low, intermediate, and high genetic groups, respectively. In conclusion, long-term exposure to air pollution was significantly associated with an elevated risk of BD. Associations of air pollution with BD occurred only within intermediate and high genetic risk categories and were even stronger at the pollutants levels below WHO air quality guidelines. These findings could help inform policy makers regarding ambient air quality standards and BD management.

Keywords: Air pollution; Bipolar disorder; Cohort study; Genetic susceptibility; Long-term exposure.

MeSH terms

Air Pollutants* / adverse effects
Air Pollutants* / analysis
Air Pollution* / adverse effects
Air Pollution* / analysis
Bipolar Disorder* / epidemiology
Bipolar Disorder* / genetics
Environmental Pollutants* / analysis
Genetic Predisposition to Disease
Humans
Incidence
Nitrogen Dioxide / analysis
Particulate Matter / adverse effects
Particulate Matter / analysis
Prospective Studies

Substances

Air Pollutants
Nitrogen Dioxide
Particulate Matter
Environmental Pollutants