Childhood serum DDE concentrations and acute lymphoblastic leukemia in a high-exposure region of south-central Mexico

Background Childhood acute lymphoblastic leukemia (ALL) is the most common pediatric cancer but its etiology remains largely unknown. Persistent organochlorine pollutants such as p,p’-DDE have been implicated in leukemogenesis, although epidemiological evidence remains scarce and contradictory. We aimed to evaluate the association between childhood serum p,p’-DDE concentrations and ALL in individuals between > 2.5 and < 20 years of age from south-central Mexico. Methods We conducted a population-based case-control study from 2021 to 2024, including 200 ALL cases and 428 controls. We obtained sociodemographic and environmental exposures information, through face-to-face interviews. We determined childhood serum p,p’-DDE concentrations by gas chromatography with an electron capture micro detector. We applied logistic regression models to assess the association between ALL and p,p’-DDE. We explored the interaction between p,p’-DDE and sex on ALL association including a multiplicative interaction term in the final adjusted model. Results Concentrations of p,p’-DDE were detected in 97.93% of serum samples. Higher serum p,p’-DDE concentrations were positively associated with ALL: compared with the lowest tertile (<357.45 ng/g), the second tertile (357.45–1216.64 ng/g) had an adjusted OR of 2.22 (95% CI: 1.34, 3.67) and the highest (>1216.64 ng/g) had an OR of 2.32 (95% CI: 1.38, 3.89). A linear association was observed for log-transformed concentrations (OR=1.25; 95% CI: 1.11, 1.40), remaining after adjusting for other organochlorine pesticides. We identified a higher association between log-transformed p,p’-DDE serum concentrations and ALL among males (OR=1.39; 95% CI: 1.17, 1.66) compared to females (OR=1.10; 95% CI: 0.92, 1.30), resulting in a positive p,p’-DDE X sex interaction (p = 0.051). Conclusion Although DDT is currently banned in most countries of the world, this substance continues to pose a potential health risk and might partially contribute to the incidence of ALL.