New study findings show that children with acute lymphoblastic leukemia (ALL) who were exposed to pesticides during their mother's pregnancy may have a higher risk of death, according to findings published in Cancers.
“This study highlights that exposures in the home environment, even before a child is born, may have lasting effects on survival after a leukemia diagnosis. While more research is needed, the findings underscore the importance of reducing children’s exposure to harmful pesticides whenever possible,” said co-study author Lena Winestone, MD, MSHP, a pediatric hematologist-oncologist at UCSF Benioff Children’s Hospitals.
Rationale and Study Methods
Previous research has shown that pesticide exposure is associated with an increased risk for developing childhood leukemia, but exposure's impact on survival and outcomes has not been explored before.
The researchers looked at the association between residential pesticide exposure during key developmental periods and 5-year survival in children with ALL. They collected parental interviews to determine the use of insecticides, herbicides, rodenticides, and flea control products between preconception through 12 months prior to the diagnosis of their child's ALL for 837 children diagnosed between 1995 and 2008 in California.
Key Study Findings
Thirteen percent of the studied children with ALL died within 5 years of their diagnosis; these children had higher exposure to any pesticides during their mother's pregnancy and/or after birth compared with children who were still alive after 5 years (95.4% vs 91.5%; P = .23).
For rodenticides specifically, the rates of use were 25% in children who died within 5 years of their ALL diagnosis vs 15.5% in those who did not (P = .02). Rodenticide exposure was associated with an increased mortality risk in adjusted models (hazard ratio [HR] = 1.70; 95% confidence interval [CI] = 1.08‒2.64; P = .02). The risk was even greater for children exposed during pregnancy (HR = 1.90; 95% CI = 1.15‒3.16; P = .01). The hazard ratio for children exposed within 12 months of their diagnosis was 1.60 (95% CI = 0.98‒2.61; P = .06).
The study authors noted that this was the first study to report reduced survival among children with ALL who were previously exposed to rodenticides during pregnancy. Although there was a greater risk for death observed with prenatal exposure to other types of pesticides, those associations were not considered statistically significant.
Higher overall death rates were observed among children diagnosed with ALL before the age of 1 year, those from families with lower rates education and income, and among Black children. White children exposed to rodenticides showed higher death rates compared with other groups. Children that were breastfed showed lower mortality risks.
“This research is a powerful reminder that cancer outcomes aren’t determined only by medical care—they’re also linked to the environmental exposures and conditions in which families live,” said first study author Seema Desai, MD, MPH, of the University of California, Berkeley School of Public Health.
The researchers also highlighted that further research needs to explore mechanisms of environmental exposure during key developmental stages and their impact on later cancer diagnoses and outcomes.
Disclosure: For full disclosures of the study authors, visit mdpi.com.
