Environmental and Prenatal Exposure to Persistent Organic Pollutants and the Risk of Asthma and Respiratory Outcomes Across the Lifespan: A Review of Emerging Epidemiological Evidence and Mechanisms

Persistent organic pollutants (POPs) are environmentally persistent, bioaccumulative contaminants that remain an important global public health concern despite international restrictions on their production and use. Owing to their lipophilicity, biomagnification within food webs, and ability to cross the placental barrier, these compounds may adversely influence immune maturation and respiratory development during critical periods of susceptibility. This narrative review synthesizes current epidemiological, clinical, and mechanistic evidence evaluating the association between prenatal and lifelong POP exposure and respiratory health outcomes. A comprehensive literature search was conducted using literature databases to identify relevant studies published between 2000 and 2025. The evidence base included major prospective birth cohorts, such as HELIX, BAMSE, ALSPAC, Generation R, COPSAC, and the Hokkaido Study, in addition to longitudinal, cross-sectional, case-control, and experimental investigations. Current evidence suggests that prenatal and early-life exposure to POPs, particularly hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and dioxin-like polychlorinated biphenyl congeners, is associated with increased risks of asthma, wheezing, allergic disease, airway obstruction, and recurrent respiratory infections. Mechanistic studies support biological plausibility through immune dysregulation, aryl hydrocarbon receptor activation, oxidative stress, inflammatory signaling, endocrine disruption, and epigenetic modifications. However, findings remain heterogeneous, and causal inference is limited by methodological variability, exposure misclassification, co-exposures, and residual confounding. Further longitudinal studies are required to clarify underlying mechanisms.