Recent findings from a large California-based case-control study published in Environmental Health Perspectives reveal a concerning link between perinatal exposure to fine particulate matter (PM2.5) and outdoor artificial light at night (O-ALAN) with increased pediatric thyroid cancer risk in children aged 0–19. Specifically, children exposed to higher PM2.5 levels at birth had a 7% increased risk per 10 μg/m³ increment. Those born in areas with the highest O-ALAN exposure were 23–25% more likely to develop pediatric papillary thyroid cancer.

Environmental Exposures and Thyroid Cancer

Both PM2.5 and O-ALAN are recognized as environmental carcinogens and endocrine disruptors, influencing thyroid function and cancer risk in adults. This pivotal study is among the first to link early-life exposure to pediatric thyroid cancer risk in a large cohort. The association was strongest among adolescents aged 15–19 and Hispanic children, suggesting age and ethnic disparities in susceptibility.

The study used advanced geospatial modeling and satellite measurements to assess exposure at the individual level based on residence at birth. This approach improved the precision of risk estimates and provided critical insights into environmental contributions to pediatric thyroid cancer.

Understanding PM2.5 and O-ALAN

Per the WHO and EPA, PM2.5 primarily comes from urban transportation, industrial emissions, and combustion. These ultrafine particles can penetrate deep into the respiratory system, disrupting hormonal and immune responses. The IARC classifies outdoor air pollution, especially PM2.5, as carcinogenic, with emerging evidence of endocrine disruption.

O-ALAN inhibits melatonin production and disrupts circadian rhythms, both linked to hormone-related cancers. Urbanization has increased artificial light exposure globally.

Economic and Health Implications

The rising incidence of pediatric thyroid cancer tied to environmental exposures may strain health systems. Increased surveillance and prevention efforts could raise healthcare costs but also create opportunities for public health initiatives targeting pollution reduction.

Key findings highlight the need for stricter environmental regulations and urban planning to reduce PM2.5 and light pollution. Such measures could improve childhood health and lower future healthcare costs. Rising thyroid cancer cases may also drive demand for new diagnostics and treatments. Payers and policymakers should consider environmental factors in health assessments.

For detailed findings, refer to the original article in Environmental Health Perspectives here.