Association of Ambient Air Pollution with Blood Pressure in Adolescence: A Systematic-review and Meta-analysis

We systematically reviewed the association of ambient air pollution with blood pressure (BP) as a primary outcome in adolescents (10-19 years). Five databases (Ovid Medline, Ovid Embase, Web of Science, The Cochrane Library, and LILACS) were searched for relevant articles published up to August 2022. Meta-analyses were conducted using STATA v17 (Protocol - OSF Registries https://doi.org/10.17605/OSF.IO/96G5Q). Eight studies (5 cohort, 3 cross-sectional) with approximately 15,000 adolescents were included. Data from 6 studies were suitable for inclusion in the meta-analyses. In sub-group analyses, non-significant positive associations were observed for cohort studies assessing long-term exposure to PM10, PM2.5, and NO2 on systolic and diastolic BP. At age 12 years old (3702 adolescents), we found significant positive associations for long-term exposure to PM2.5(beta=5.33 (1.56, 9.09) mmHg) and PM10 (beta=2.47 (0.10, 4.85) mmHg) on diastolic BP. Significant positive associations were observed (3,592 adolescents) for long-term exposure to PM10(beta=0.34 (0.19, 0.50) mmHg) and NO2 on diastolic BP (beta=0.40 (0.09, 0.71) mmHg), and PM10 on systolic BP (beta=0.48 (0.19, 0.77) mmHg). The overall quality of evidence analysed was graded as low/very low. Insufficient data for short-term exposures to PM2.5, PM10, NO2, CO on BP led to their exclusion from the meta-analysis. Inconsistent associations were reported for gender-stratified results. The evidence, though of low-quality and limited, indicated that ambient air pollution was positively associated with adolescent BP. Future studies need improved measures of air pollutant exposures, consideration of gender and socio-economic circumstances on the observed pollution effects, as well as adjustment for other potential confounding factors.

Automated summary

This study systematically reviewed the association between ambient air pollution and blood pressure in adolescents. The analysis of eight studies with approximately 15,000 adolescents revealed generally positive but non-significant associations between long-term exposure to PM10, PM2.5, and NO2 and blood pressure. However, at age 12, significant positive associations were found between long-term exposure to PM2.5 and PM10 and diastolic blood pressure.