Table 1.
Associations between organophosphates (OPs) and autism spectrum disorder (ASD).
| Authors and Year | Study Design | Sample Size | ASD Outcome Assessment | Exposure Assessment | Method of Analysis | Adjustment Variables | Time Window of Exposure | Main Findings |
|---|---|---|---|---|---|---|---|---|
| von Ehrenstein et al., 2019 | Case–control | 2961 ASD cases and 10:1 controls |
Diagnosis of autism spectrum disorder based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. | Data from California state mandated Pesticide Use Reporting were integrated into a GIS (Geographical Information System) tool to estimate prenatal and infant exposures to pesticides. | Multivariable logistic regression model | Sex, year of birth, maternal age, maternal race/ethnicity, education and nitrogen oxides. | Pregnancy | Association with prenatal exposures to glyphosate with an odds ratio (OR) of 1.16 (95% confidence interval 1.06, 1.27), chlorpyrifos with an OR of 1.13 (95% CI 1.05, 1.23), diazinon with an OR of 1.11 (95% CI 1.01, 1.21) and malathion with an OR of 1.11 (95% CI 1.01, 1.22). |
| Shelton et al., 2014 | Case–control | 486 ASD case and 316 controls |
Diagnoses of ASD were confirmed combining the Autism Diagnostic Interview, Revised (ADI®-R) and the Autism Diagnostic Observation Scale (ADOS). | Commercial pesticide application data from the California Pesticide Use Report (1997–2008) were linked to the addresses during pregnancy. | Multinomial logistic regression | Paternal education home ownership (binary), maternal place of birth child race/ethnicity and maternal prenatal vitamin intake. | Each trimester pregnancy, pregnancy and preconception | Proximity to orgnanophosphates during gestation was associated with a 60% increased risk of ASD and became higher with third-trimester exposures with an OR of 2.0 (95% CI 1.1, 3.6) and second-trimester exposures with an OR of 3.3 (95% CI: 1.5, 7.4). |
| Schmidt et al., 2017 | Case–control | 296 ASD cases and 220 controls |
Diagnoses of ASD were confirmed by using the Autism Diagnostic Interview, Revised (ADI®-R) and the Autism Diagnostic Observation Schedule–Generic (ADOS-G). | Maternal supplemental folic acid (FA) and household pesticide product use were retrospectively collected in telephone interviews from 2003–2011. | Logistic regression models | Intake of vitamins B6 and D in the first month of pregnancy, home ownership and child’s year of birth. | Pregnancy | In particular, the risk of ASD associated with prenatal exposure to organochlorine pesticides had an OR of 0.8 (95% CI 0.5, 1.6) in mothers who took high amounts of FA in the first month of pregnancy and an OR of 2.3 (95% CI 0.98, 5.3) in mothers who took low amounts of FA in the first month of pregnancy. |
| Sagiv et al., 2018 | Cohort | 600 children | Autistic-related traits assessed with Social Responsiveness Scale, Version 2 (SRS-2) and meeting Diagnostic and Statistical Manual of Mental Disorders −5 (DSM-5) criteria for ASD. | California’s Pesticide Use Reporting (PUR) data. | Linear regression models | Maternal age, education, country of birth, marital status, depression, child’s age at assessment, sex and quality of the home environment. | Pregnancy | No clear evidence of associations between residential proximity to OP use during pregnancy and ASD-related traits. |