Air pollution and mortality in acute lymphoblastic leukemia patients across different age groups in Northern Thailand (1999-2020).

This study investigated the impact of air pollution on 604 patients diagnosed with acute lymphoblastic leukemia (ALL) between 1999 and 2020 in upper northern Thailand. Patients were categorized into three age groups: pediatric (<15 years), adolescent and young adult (AYA) (15-39 years), and adult (≥40 years). The cohort included 344 (57.0%) pediatric, 152 (25.1%) AYA, and 108 (17.9%) adult patients, with 5-year survival rates of 64.5%, 19.6%, and 6.7%, respectively. Concentrations of PM2.5, PM10, O₃, and CO were significantly higher in patients who died, particularly among pediatric cases. Among AYA patients, those who died had higher levels of PM2.5, PM10, and CO than survivors. Compared to the pediatric group, the risk of death was higher in AYA (adjusted hazard ratio [aHR]: 3.76) and adult (aHR: 8.10) groups. Patients diagnosed before 2010 had an increased risk of death (aHR: 1.38). Notably, PM2.5 levels ≥50 µg/m³ were associated with increased mortality in pediatric patients. These findings highlight the adverse effects of air pollution on survival outcomes in ALL patients, particularly children under 15 years of age.