Long-term exposure to ambient air pollutants and their interaction with physical activity on insomnia: A prospective cohort study

Yijuan Lin; Yinyan Gao; Xuemei Sun; Jiali Wang; Shuzi Ye; Irene X Y Wu; Fang Xiao

doi:10.1016/j.envres.2023.115495

Long-term exposure to ambient air pollutants and their interaction with physical activity on insomnia: A prospective cohort study

Environ Res. 2023 May 1:224:115495. doi: 10.1016/j.envres.2023.115495. Epub 2023 Feb 20.

Authors

Yijuan Lin¹, Yinyan Gao¹, Xuemei Sun¹, Jiali Wang¹, Shuzi Ye¹, Irene X Y Wu¹, Fang Xiao²

Affiliations

¹ Xiangya School of Public Health, Central South University, Changsha, 410078, PR China.
² Xiangya School of Public Health, Central South University, Changsha, 410078, PR China. Electronic address: fangxiao@csu.edu.cn.

PMID: 36813065
DOI: 10.1016/j.envres.2023.115495

Abstract

Exposure to air pollution or lack of physical activity (PA) increases the risk of insomnia. However, evidence on joint exposure to air pollutants is limited, and the interaction of joint air pollutants and PA on insomnia is unknown. This prospective cohort study included 40,315 participants with related data from the UK Biobank, which recruited participants from 2006 to 2010. Insomnia was assessed by self-reported symptoms. The annual average air pollutant concentrations of particulate matter (PM_2.5, PM₁₀), nitrogen oxides (NO₂, NO_X), sulfur dioxide (SO₂) and carbon monoxide (CO) were calculated based on participants' addresses. We applied a weighted Cox regression model to evaluate the correlation between air pollutants and insomnia and newly proposed an air pollution score to assess joint air pollutants effect using a weighted concentration summation after obtaining the weights of each pollutant in the Weighted-quantile sum regression. With a median follow-up of 8.7 years, 8511 participants developed insomnia. For each 10 μg/m³ increase in NO₂, NO_X, PM₁₀, SO₂, the average hazard ratios (AHRs) and 95% confidence interval (CI) of insomnia were 1.10 (1.06, 1.14), 1.06 (1.04, 1.08), 1.35 (1.25, 1.45) and 2.58 (2.31, 2.89), respectively; For each 5 μg/m³ increase in PM_2.5 and each 1 mg/m³ increase in CO, the corresponding AHRs (95%CI) were 1.27 (1.21, 1.34) and 1.83 (1.10, 3.04), respectively. The AHR (95%CI) for insomnia associated with per interquartile range (IQR) increase in air pollution scores were 1.20 (1.15, 1.23). In addition, potential interactions were examined by setting cross-product terms of air pollution score with PA in the models. We observed an interaction between air pollution scores and PA (P = 0.032). The associations between joint air pollutants and insomnia were attenuated among participants with higher PA. Our study provides evidence on developing strategies for improving healthy sleep by promoting PA and reducing air pollution.

Keywords: Ambient air pollutants; Insomnia; Interaction; Long-term exposure; Physical activity; Prospective cohort study.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Environmental Exposure / analysis
Environmental Pollutants*
Humans
Nitrogen Dioxide
Particulate Matter / analysis
Prospective Studies
Sleep Initiation and Maintenance Disorders*

Substances

Air Pollutants
Environmental Pollutants
Nitrogen Dioxide
Particulate Matter