Study findings published in the American Journal of Psychiatry revealed that maternal exposure to insecticides during pregnancy was linked to autism in offspring.
“Autism is a neurodevelopmental disorder that causes substantial distress and impairments in psychological and social functioning, and its causes remain largely unknown,” Alan S. Brown, MD, MPH, professor of psychiatry and epidemiology at Columbia University Medical Center and director of the unit in birth cohort studies at New York State Psychiatric Institute, told Infectious Diseases in Children. “Organic pollutants such as pesticides are widespread in the population. Research on this topic offers potential for prevention and a better understanding of the developmental mechanisms that influence brain development and risk for autism.”
Using maternal biomarkers of exposure, researchers examined the relationship between elevated maternal levels of persistent organic pollutants and autism in offspring using data derived from a Finnish national birth cohort study.
In the study, persistent organic pollutants included the insecticide dichlorodiphenyltrichloroethane (DDT), its metabolite p,p:-dichlorodiphenyl dichloroethylene (p,p:-DDE) and polychlorinated biphenyls (PCBs). The investigators examined cases of autism in children born between 1987 and 2005. To determine levels of p,p:-DDE and total levels of PCBs, they assessed maternal serum specimens from early pregnancy in cases of childhood autism and matched control participants (n = 778 pairs).
When maternal p,p:-DDE levels were in the top 75th percentile of the control distribution, the odds of autism in offspring were increased by 32%, adjusting for maternal age, parity and history of psychiatric disorders (OR = 1.32; 95% CI, 1.02-1.71). However, there was no increase in the odds of autism for maternal PCBs exposure above the 75th percentile. Furthermore, the link between high maternal p,p:-DDE levels and the odds of autism was significant among boys (OR = 1.35; 95% CI, 1.02-1.8) but not girls.
The results also showed that the odds of autism with intellectual disability were higher when mothers had p,p:-DDE levels above the 75th percentile threshold (OR = 2.21; 95% CI, 1.32-3.69) compared with case participants without intellectual disability.
“Clinicians will be more aware that there may be important environmental contributors to autism, particularly in pregnant patients, and consider recommending measures aimed at reducing exposure to organic pollutants, including pesticides,” Brown said.
The researchers emphasized that these results need to be replicated in future studies – by Savannah Demko
- Brown AS, et al. Am J Psychiatr. 2018;doi:10.1176/appi.ajp.2018.17101129.
Disclosures: The authors report no relevant financial disclosures.