Information that helps elucidate the enigmatic origins of autism and further identify risk factors for disease development is a welcome result for many current scientific endeavors. Now, new data from investigators at Kaiser Permanente Southern California (KPSC) and the University of Southern California Keck School of Medicine shows that the risk of autism spectrum disorder (ASD) was increased in children of mothers with the three main types of diabetes that complicate pregnancy. Findings from the new study—published recently in JAMA, in an article entitled “Maternal Type 1 Diabetes and Risk of Autism in Offspring”—add new information on type 1 diabetes (T1D) and extend what is already known about type 2 (T2D) and gestational diabetes mellitus (GDM).
“Maternal preexisting type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) diagnosed by 26 weeks’ gestation has been associated with increased risk of autism spectrum disorder (ASD) in offspring,” the authors wrote. “However, little is known about ASD risk associated with maternal preexisting type 1 diabetes (T1D). We extend previous observations by examining the risk of ASD in offspring associated with maternal T1D, T2D, and GDM.”
For the current study, the researchers assembled a retrospective cohort study including singleton children born at 28 to 44 weeks’ gestation (419,425 total) in KPSC hospitals from January 1, 1995, through December 31, 2012. Electronic health records were utilized to track children from age one until clinical diagnosis of ASD, last date of continuous KPSC membership, death, or study end date (December 31, 2017). This was an observational study. Researchers were not intervening for purposes of the study and could not control all the natural differences that could explain the study findings.
The study investigators found that “of 419,425 children (boys, 51%) meeting study criteria, 621 were exposed to maternal T1D, 9453 to maternal T2D, 11,922 to GDM diagnosed by 26 weeks’ gestation, and 24,505 to GDM diagnosed after 26 weeks’ gestation. During a median follow-up of 6.9 years (interquartile range, 3.4-11.9), 5827 children were diagnosed with ASD. Unadjusted average annual ASD incidence rates per 1000 children were 4.4 for exposure to T1D; 3.6 for T2D; 2.9 for GDM by 26 weeks; 2.1 for GDM after 26 weeks; and 1.8 for no diabetes.”
These results led the authors to surmise that the risk of ASD was higher in children exposed in utero to maternal preexisting T1D, T2D, and GDM diagnosed by 26 weeks compared with no maternal diabetes exposure.
“These results suggest that the severity of maternal diabetes and the timing of exposure (early vs. late in pregnancy) may be associated with the risk of ASD in offspring of diabetic mothers,” the study authors concluded.