Polycyclic aromatic hydrocarbons exposure in humans and reproductive health outcomes: An umbrella review

Abstract

Background: Polycyclic aromatic hydrocarbons (PAHs) are a public health threat, but evidence linking PAHs exposure to adverse reproductive health outcomes remains unclear. Methods: PubMed, Embase, and Web of Science were searched from inception to April 17, 2024, for systematic reviews and meta-analyses of observational studies on PAHs exposure and reproductive outcomes. Methodological quality was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR). Random-effects models generated pooled estimates, without conversion among beta coefficients (β), odds ratios (OR), and risk ratios (RR). Evidence credibility was evaluated using evidence-class criteria and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results: Five articles reporting 15 associations were included. Four (26.7%) were significant: bladder cancer in aluminum production workers (RR = 1.26, 95% CI= 1.16, 1.36) and iron and steel foundry workers (RR = 1.36, 95% CI= 1.14, 1.62), birth weight reduction associated with PAHs DNA-adducts (OR = 1.02, 95% CI = 1.01, 1.03), and offspring attention deficit hyperactivity disorder (ADHD) associated with prenatal PAHs exposure (RR = 1.73, 95% CI = 1.15, 2.58). Dietary PAHs were not associated with birth length (β = -0.04, 95% CI = -0.09, 0.01) or birth weight (β = -5.65, 95% CI = -16.35, 5.06). Overall, the certainty of evidence was generally low or very low. Conclusion: Occupational and prenatal PAHs exposures may be associated with adverse outcomes, but evidence was low or very low certainty, and most birth-size outcomes showed no significant pooled associations.