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

Abstract

Objectives Associations between parental occupational pesticide exposure and childhood acute lymphoblastic leukemia (ALL) vary across studies, likely due to different exposure assessment methodologies. Methods 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 1,021controls. 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. Results 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. Conclusions 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.

Parental occupational exposure to pesticides, animals and organic dust and risk of childhood leukemia and central nervous system tumors: Findings from the International Childhood Cancer Cohort Consortium (I4C)

“…Our use of JEMs will likely have introduced some nondifferential misclassification of parental occupational exposures since we were not able to assess specific job tasks. In a large case–control study of ALL, Gunier et al . identified occupational pesticide exposure misclassification in 9.4% of fathers and 2.6% of mothers when using a JEM compared to job modules; however, this study showed high specificity with the JEM for both maternal (98%) and paternal (90%) assessments, which is important in reducing the likelihood of bias from exposure misclassification when exposure prevalence is low.…”

“…Our use of JEMs will likely have introduced some nondifferential misclassification of parental occupational exposures since we were not able to assess specific job tasks. In a large case-control study of ALL, Gunier et al 33 identified occupational pesticide exposure misclassification in 9.4% of fathers and 2.6% of mothers when using a JEM compared to job modules; however, this study showed high specificity with the JEM for both maternal (98%) and paternal (90%) assessments, which is important in reducing the likelihood of bias from exposure misclassification when exposure prevalence is low. Additionally, our JEM did not account for changes in these occupational exposures over the different time periods of our cohorts or regional differences in exposures; however, the two Nordic cohorts contributing the most person-years and cases (DNBC and MoBa) were conducted in a similar time frame and would be likely to have more similar exposures for many of the same jobs.…”

Association of Occupational Pesticide Exposure With Immunochemotherapy Response and Survival Among Patients With Diffuse Large B-Cell Lymphoma

“…The use of a JEM, which is more sensitive and less specific than job exposure modules based on specific tasks, is likely to attenuate the OR. 29 We performed 4 analyses using JEM probability and reliability threshold for occupational exposure. The first analysis included all patients with low or high probability of exposure; another analysis considered only agricultural exposure, which is the better known according to the literature; another analysis considered high probability (>75%); and the last one considered high probability and reliability.…”

Pesticide Determination in Water Samples from a Rural Area by Multi-Target Method Applying Liquid Chromatography-Tandem Mass Spectrometry

“…15,16 Recent studies have shown that the exposure of parents before a child's birth increases the risk of infant leukemia and Parkinson's disease to 70%. 17,18 At the South of Brazil, the Paraná State is known for the intensive production and commercialization of pesticides, occupying the third position according to the report made by the Ministries of Health in 2016 and of Agriculture in 2018. 19 The discrepancy might be related to the presence of 36 industries of pesticides in the state.…”