Children exposed to traffic-related air pollution face a significantly higher risk of developing childhood cancers, according to a comprehensive meta-analysis of international research. The study, which synthesized findings from over three decades of data, identified a clear correlation between exposure to pollutants like fine particulate matter and nitrogen dioxide and an increased incidence of specific childhood leukemias and retinoblastoma.
Key Findings on Air Pollution and Childhood Cancer
A joint research team, including experts from the National Cancer Center and Ewha Womans University College of Medicine, analyzed 1632 relevant studies published between 1990 and 2024. After applying stringent selection criteria, 25 studies were chosen for a meta-analysis, a method that combines results from multiple independent studies to identify common trends. The pollutants examined included fine particulate matter (PM2.5), nitrogen dioxide, and benzene, all commonly found in vehicle exhaust and road dust.
Fine particulate matter, particles less than 1/20th the thickness of a human hair, can penetrate deep into the lungs or enter the bloodstream. Benzene, a component of vehicle exhaust and petrochemical products, is classified as a carcinogen by the International Agency for Research on Cancer.
Specific Cancer Risks Identified
- Acute Lymphoblastic Leukemia (ALL): For every 10 μg/m³ increase in PM2.5 concentration, the risk of developing ALL in children rose by 29%. ALL is the most common type of leukemia in children, characterized by the abnormal proliferation of immature white blood cells.
- Retinoblastoma: The risk of retinoblastoma, a cancer of the retina primarily affecting infants and young children, increased by 68% with higher PM2.5 exposure.
- General Childhood Leukemia: A 1 μg/m³ increase in benzene levels was associated with a 12% rise in the overall risk of childhood leukemia.
- Acute Myeloid Leukemia (AML): The risk of AML also saw an increase of 22% with a 1 μg/m³ rise in benzene concentration.
Postnatal Exposure More Critical
The research team noted a particularly strong association between traffic-related air pollution exposure during infancy and early childhood and an increased risk of childhood leukemia. While prenatal exposure to pollutants was also considered, the impact of exposure after birth appeared more significant in the study’s findings.
Unlike adult cancers, which are often linked to lifestyle factors like smoking and alcohol consumption over extended periods, childhood cancers can be more heavily influenced by genetic factors and environmental exposures during critical growth periods. The study suggests that inhaled pollutants can trigger inflammatory responses and oxidative stress within the body, potentially damaging the cells and DNA of developing children.
Call for Policy Action and Further Research
Dr. Byung-mi Kim, a researcher at the National Cancer Center’s Cancer Prevention Branch and a participant in the study, emphasized the systematic confirmation of the link between traffic-related air pollution and increased risks for specific childhood cancers. “This research systematically confirms that exposure to traffic-related air pollution can elevate the risk of developing certain childhood cancers, including leukemia,” Dr. Kim stated.
“To protect children’s health, we need more aggressive policy measures to reduce exposure to air pollutants, alongside continuous follow-up research,” she added. The findings underscore the urgent need for stricter environmental regulations and public health initiatives aimed at mitigating air pollution, particularly in areas with high traffic density.
