Air Pollution and Brain Tumors in Children. A Systematic Review

Prenatal and early-life exposures to environmental pollutants may significantly influence the risk of childhood brain tumors. This systematic review critically appraised and synthesized existing epidemiological evidence on the association between air pollution exposure and childhood brain tumor risk. Following PRISMA guidelines and registered with PROSPERO (CRD420251071700), four databases were searched without date restrictions, yielding 14 eligible studies from the USA, Europe, and Australia. Study designs included case-control, cross-sectional, and cohort approaches. Pollutants examined encompassed particulate matter (PM10, PM2.5), nitrogen dioxide (NO2), black carbon (BC), BTEX compounds, 1,3-butadiene, formaldehyde, chloroform, acetaldehyde, styrene, PAHs, heavy metals, and parental passive smoking. Evidence from the reviewed studies indicates that prenatal and early-life exposure to polycyclic aromatic hydrocarbons (PAHs) was most consistently associated with an increased risk of childhood brain tumors, particularly primitive neuroectodermal tumors (PNET) and medulloblastoma. Associations with other pollutants, particularly BTEX, 1,3-butadiene, formaldehyde, chloroform, acetaldehyde, styrene, cobalt (Co), and selenium (Se), as well as general PM, NO2, and BC, were limited, inconsistent, or based on single studies. Key limitations included exposure misclassification, small sample sizes, and residual confounding, limiting causal inference. These findings emphasize the heightened vulnerability of developing children and the urgent need for public health interventions, including stricter air-quality standards, reduced traffic and industrial emissions, systematic exposure monitoring, and protection of pregnant women and children.