A task-based assessment of parental occupational exposure to pesticides and childhood acute lymphoblastic leukemia

• Published in: Environmental research 2017-07, Vol.156, p.57-62
• Main Authors: Gunier, Robert B., Kang, Alice, Hammond, S. Katharine, Reinier, Kyndaron, Lea, C. Suzanne, Chang, Jeffrey S., Does, Monique, Scelo, Ghislaine, Kirsch, Janice, Crouse, Vonda, Cooper, Robert, Quinlan, Patricia, Metayer, Catherine
• Format: Article
• Language: English
• Subjects: Adolescent; California - epidemiology; Child; Child, Preschool; Childhood leukemia; Female; Humans; Infant; Infant, Newborn; Job-specific modules; Logistic Models; Male; Maternal Exposure; Occupational Exposure; Paternal Exposure; Pesticides; Pesticides - toxicity; Precursor Cell Lymphoblastic Leukemia-Lymphoma - chemically induced; Precursor Cell Lymphoblastic Leukemia-Lymphoma - epidemiology; Pregnancy; Prenatal Exposure Delayed Effects - chemically induced; Prenatal Exposure Delayed Effects - epidemiology
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2017.03.001

Associations between parental occupational pesticide exposure and childhood acute lymphoblastic leukemia (ALL) vary across studies, likely due to different exposure assessment methodologies. We assessed parental occupational pesticide exposure from the year before pregnancy to the child's third year of life for 669 children diagnosed with ALL and 1021 controls. We conducted expert rating using task-based job modules (JM) to estimate exposure to pesticides among farmer workers, gardeners, agricultural packers, and pesticide applicators. We compared this method to (1) partial JM using job titles and a brief description, but without completing the task-based questionnaire, and (2) job exposure matrix (JEM) linking job titles to the International Standard Classifications of Occupation Codes. We used unconditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for ALL cancer risk and pesticide exposure adjusting for child's sex, age, race/ethnicity and household income. Compared to complete JMs, partial JMs and JEM led to 3.1% and 9.4% of parents with pesticide exposure misclassified, respectively. Misclassification was similar in cases and controls. Using complete JMs, we observed an increased risk of ALL for paternal occupational exposure to any pesticides (OR=1.7; 95% CI=1.2, 2.5), with higher risks reported for pesticides to treat nut crops (OR=4.5; 95% CI=0.9, 23.0), and for children diagnosed before five years of age (OR=2.3; 95% CI: 1.3, 4.1). Exposure misclassification from JEM attenuated these associations by about 57%. Maternal occupational pesticide exposure before and after birth was not associated with ALL. The risk of ALL was elevated in young children with paternal occupational pesticide exposure during the perinatal period, using more detailed occupational information for exposure classification. •Paternal occupational pesticide exposure increased the risk of ALL in offspring.•The relationship was stronger for children diagnosed before five years of age.•The relationship was attenuated when less detailed exposure information was used.•Perinatal maternal occupational pesticide exposure was not associated with ALL.