Exposure to Particulate Matter (PM) During Pregnancy and Non-Hodgkin Lymphomas in Children.

Background/

Objectives

Lymphomas are the third most common pediatric malignancy, with non-Hodgkin lymphoma (NHL) comprising around 7% of childhood cancers. Environmental exposures have been linked to its etiology. Particulate matter (PM) prenatal exposure is increasingly scrutinized for potential effects on early-life carcinogenesis. We investigated whether exposure during pregnancy to PM2.5 and PM10 was associated with childhood NHL incidence.

Methods

A population-based case-control study was conducted in Spain (2009-2016), including 3,682,038 children < 15 years. Incident NHL cases (n = 289) were identified through the Spanish Childhood Tumor Registry. Prenatal PM2.5 and PM10 exposures were estimated using a random forest model. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs). Exposures were modeled continuously and categorically by tertiles (low, medium, or high exposure) to assess nonlinearity; trimester-specific analyses were also explored.

Results

In the analysis with the continuous exposure, higher prenatal PM2.5 was associated with increased odds of NHL, and PM10 showed smaller associations. With categorical variables, medium and high-level exposure to PM2.5 showed an association with higher NHL incidence, especially in the third trimester. High-level exposure to PM10 during the first and second trimesters was linked to a higher NHL incidence in children under five years.

Conclusions

Maternal PM2.5 and PM10 exposure during pregnancy could be associated with childhood NHL incidence, with stronger associations among children diagnosed before age 5. These findings warrant replication and mechanistic investigation.