Effects of Ambient Air Pollution on Blood Pressure Among Children and Adolescents: A Systematic Review and Meta-Analysis.

Background Previous studies have investigated the association of ambient air pollution with blood pressure (BP) in children and adolescents, however, the results are not consistent. We conducted a systematic review and meta-analysis to assess the relationship between short-term and long-term ambient air pollutant exposure with BP values among children and adolescents. Methods and Results We searched PubMed, Web of Science, and Embase before September 6, 2020. Two reviewers independently searched and selected studies, extracted data, and assessed study quality. The studies were divided into groups by composition of air pollutants (NO2, particulate matter (PM) with diameter ≤10 μm or ≤2.5 μm) and length of exposure. The beta regression coefficients (β) and their 95% CIs were calculated to evaluate the strength of the effect with each 10 μg/m3 increase in air pollutants. Out of 36 650 articles, 14 articles were included in this meta-analysis. The meta-analysis showed short-term exposure to PM with diameter ≤10 μm (β=0.267; 95% CI, 0.033‒0.501) was significantly associated with elevated systolic BP values. In addition, long-term exposure to PM with diameter ≤2.5 μm (β=1.809; 95% CI, 0.962‒2.655), PM with diameter ≤10 μm (β=0.526; 95% CI, 0.095‒0.958), and NO2 (β=0.754; 95% CI, 0.541‒0.968) were associated with systolic BP values and long-term exposure to PM with diameter ≤2.5 μm (β=0.931; 95% CI, 0.157‒1.705), and PM with diameter ≤10 μm (β=0.378; 95% CI, 0.022‒0.735) was associated with diastolic BP. Conclusions Our study indicates that both short-term and long-term exposure to some ambient air pollutants may increase BP values among children and adolescents.