Exposure to air pollution and cognitive impairment risk: a meta-analysis of longitudinal cohort studies with dose-response analysis

J Glob Health. 2020 Jun;10(1):010417. doi: 10.7189/jogh.10.010417.

Abstract

Background: We conducted a meta-analysis to explore the relationship between exposure to air pollution and the risk of cognitive impairment of longitudinal cohort studies.

Methods: PubMed, Web of Science and Wan Fang databases were searched for relevant articles of longitudinal cohort studies published between January 1950 and September 2019. The pooled relative ratio (RR) and 95% confidence interval (CI) were calculated using the random effect model.

Results: Ten articles involving 519 247 cases among 12 523 553 participants were included in this meta-analysis. The pooled RR of cognitive impairment per 5 μg/m3 increments in exposure to particulate matter ≤2.5 μm (PM2.5) was 1.08 (95% CI = 1.03, 1.13; I2 = 82.2%; Pheterogeneity <0.001). No association was found between nitrogen dioxide/nitrogen oxide (NO2/NOx) and ozone (O3) and cognitive impairment. For PM2.5 exposure, in subgroup analysis, the above-mentioned significant positive association was found among studies conducted in population (RR p er 5 μg/m 3 = 1.05; 95% CI = 1.01,1.09; I2 = 57.4%; Pheterogeneity = 0.016), in North America (RR per 5 μg/m 3 = 1.13; 95% CI = 1.01,1.26; I2 = 86.7%; Pheterogeneity <0.001) and with follow-up duration >10 years (RR p er 5 μg/m 3 = 1.10; 95% CI = 1.03,1.17; I2 = 86.3%; Pheterogeneity <0.001).

Conclusions: This meta-analysis suggests that exposure to PM2.5 might increase the risk of cognitive impairment.

Publication types

  • Meta-Analysis

MeSH terms

  • Air Pollution / adverse effects*
  • Cognitive Dysfunction / diagnosis*
  • Cohort Studies
  • Environmental Exposure / adverse effects*
  • Humans
  • Longitudinal Studies
  • Ozone / analysis
  • Particulate Matter / adverse effects*
  • Particulate Matter / analysis

Substances

  • Particulate Matter
  • Ozone