Kaiser Permanente study adds to evidence that neurodevelopmental disorders may have ties to inflammation in mother
Mothers with asthma or obesity during pregnancy had higher rates of children diagnosed with autism, according to a new Kaiser Permanente analysis published in the journal Biological Psychiatry: Global Open Science.
The study adds to evidence that maternal inflammation could affect neurodevelopment in children, said study lead author Lisa Croen, PhD, a senior research scientist and director of the Autism Research Program in the Kaiser Permanente Division of Research.
“There have been studies showing that conditions during pregnancy, such as obesity, infection, fever, and gestational diabetes are related to autism,” Croen said. “We wanted to look at these factors both individually and in combination to find out if there is a profile of mothers who have a higher likelihood of having an autistic child.”
The analysis found mothers with asthma were 62% more likely to deliver an infant later diagnosed with autism spectrum disorder; developmental disabilities were 30% more likely. In mothers with obesity, autism was 51% more likely, and risk increased with extreme obesity.
The association with autism was even stronger among mothers with both asthma and obesity.
There were also differences by the child’s gender; the likelihood of an autism diagnosis related to maternal asthma and hypertension was significantly higher in girls than boys.
The study population was from the Immune and Metabolic Markers during Pregnancy and Child Development study (IMPaCT), which included children aged 3 to 8 and born at Kaiser Permanente Northern California between 2011 and 2016. There were 311 children diagnosed with autism; 1,291 children with developmental disorders involving intellectual disability, cerebral palsy, language delay, motor disorder, global delay, or learning disorder; and 967 children who served as comparisons.
The researchers initially looked at 10 maternal health conditions during pregnancy that relate to the hypothesis of inflammation and autism. The mothers’ medical records were examined for diagnoses of infection, asthma, allergy, gestational diabetes, preeclampsia, hypertension, and obesity. They found that asthma — a condition that causes systemic inflammation — and obesity, which may be related to metabolic disorder, stood out.
This analysis provides the research community with directions to pursue in future studies, to paint a more complete picture of what might be happening in the origins of autism.
—Lisa Croen, PhD
These medical conditions were chosen to study because they relate to maternal “immune activation,” which could affect the immune, metabolic, and neurological systems of the fetus with long-lasting effects into adulthood. Other epidemiological studies have found associations between neurodevelopmental disorders and maternal immune-related conditions such as infection, asthma, allergy, autoimmune disease, and cardiometabolic conditions such as hypertension and gestational diabetes.
“What all these conditions have in common is fluctuations of maternal inflammatory molecules during pregnancy, which can have adverse developmental consequences for the fetus,” Croen said.
The study adds to researchers’ understanding of the potential origins of autism but should not be of immediate concern to pregnant patients, she said. “This analysis provides the research community with directions to pursue in future studies, to paint a more complete picture of what might be happening in the origins of autism,” she said.
The researchers also explored whether maternal genetics played a role in the association and could not find a relationship. The researchers looked specifically at genetic risk factors for asthma and obesity in the mothers to see whether these would proportionately increase risk for neurodevelopmental outcomes in the children but found no evidence for this model. The mothers all participated in the Research Program on Genes, Environment, and Health pregnancy cohort, which involved providing a blood sample during the first and second trimesters of pregnancy.
The study was funded by the National Institute of Child Health and Human Development.
Co-authors included Jennifer Ames, PhD, Yinge Qian, PhD, Stacey Alexeeff, PhD, and Erica Gunderson, PhD, of the Division of Research; Paul Ashwood, PhD, and Judy Van de Water, PhD, of the University of California, Davis; Yvonne W. Wu, MD, and Andrew S. Boghossian and Lauren A. Weiss, PhD, of the University of California, San Francisco; and Robert Yolken, MD, of Johns Hopkins University.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and society at large. It seeks to understand the determinants of illness and well-being, and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 450 epidemiological and health services research projects. For more information, visit divisionofresearch.kaiserpermanente.org or follow us @KPDOR.