Long-term exposure to ambient nitrogen dioxide and ozone modifies systematic low-grade inflammation: The CHCN-BTH study

Int J Hyg Environ Health. 2022 Jan:239:113875. doi: 10.1016/j.ijheh.2021.113875. Epub 2021 Oct 29.

Abstract

The potential effect of long-term exposure to ambient air pollutants on low-grade systematic inflammation has seldom been evaluated taking indoor air pollution and self-protection behaviors on smog days into account. A total of 24,346 participants at baseline were included to conduct a cross-sectional study. The annual (2016) average pollutant concentrations were assessed by air monitoring stations for PM2.5, PM10, SO2, NO2, O3 and CO. Associations between annual ambient air pollution and low-grade systematic inflammation (hsCRP>3 mg/L) were estimated by generalized linear mixed models. Stratification analysis was also performed based on demographic characteristics, health-related behaviors and disease status. Annual ambient NO2 and O3 were all associated with low-grade systematic inflammation in single-pollutant models after adjusting for age, sex, blood lipids, blood pressure, lifestyle risk factors, cooking fuel, heating fuel and habits during smog days (NO2 per 10 μg/m3: OR = 1.057, P = 0.018; O3 per 10 μg/m3: OR = 0.953, P = 0.012). The 2-year and 3-year ozone concentrations were consistently associated with lower systematic inflammation (2-year O3 per 10 μg/m3: OR = 0.959, P = 0.004; 3-year O3 per 10 μg/m3: OR = 0.961, P = 0.014). In two-pollutant models, the estimated effects of annual NO2 and O3 on low-grade systematic inflammation remained stable. The effect size of annual pollutants on inflammation increased in participants without air-purifier usage (NO2 per 10 μg/m3: OR = 1.079, P = 0.009; O3 per 10 μg/m3: OR = 0.925, P = 0.001), while the association was null in the air-purifier usage group. Thus, long-term exposure to ambient NO2 and O3 was associated with low-grade systemic inflammation, and the results were generally stable after sensitivity analysis. The usage of air purifiers on smog days can modify the association between gaseous pollutants and systematic inflammation.

Keywords: Long-term gaseous pollutant; Low-grade systematic inflammation; Nitrogen dioxide; Ozone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Air Pollutants* / analysis
  • Air Pollution* / analysis
  • Cross-Sectional Studies
  • Environmental Exposure / analysis
  • Humans
  • Inflammation
  • Nitrogen Dioxide / analysis
  • Ozone* / analysis
  • Particulate Matter / analysis

Substances

  • Air Pollutants
  • Particulate Matter
  • Ozone
  • Nitrogen Dioxide