JAMA Letter: Autism Risk Higher When Mother Has Type 1 Diabetes

The risk of autism spectrum disorder (ASD) in children was higher in mothers with type 1 diabetes (T1D) diagnosed by 26 weeks’ gestation, according to a new research letter in JAMA.

The risk of ASD in offspring of mothers with type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) diagnosed by 26 weeks’ gestation was also higher, although that association was known previously, the researchers said. However, GDM diagnosed after 26 weeks’ gestation was not associated with an increased risk.

The researchers said the results suggest that the severity of maternal diabetes and the timing of exposure—early versus late in pregnancy—may be a factor.

This retrospective study using electronic health records included singleton children born at 28 to 44 weeks’ gestation in Kaiser Permanente Southern California (KPSC) hospitals from January 1, 1995, through December 31, 2012. Children were tracked through from age 1 until the first date of the following: clinical diagnosis of ASD, last date of continuous KPSC membership, death, or study end date of December 31, 2017.

Of the 419,425 children (boys, 51%) who met the 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
• 1.8 for no diabetes

Relative to no diabetes exposure, the adjusted hazard ratios for exposure to maternal diabetes were 2.36 (95% CI, 1.36-4.12) for T1D; 1.45 (95% CI, 1.24-1.70) for T2D; 1.30 (95% CI, 1.12-1.51) for GDM by 26 weeks’ gestation; and 0.99 (95% CI, 0.88-1.12) for GDM after 26 weeks.

Confounding due to risk factors from the father and other intrauterine and postnatal exposures could not be assessed, the researchers said. Further areas for study include the potential role of maternal glycemia; other features of T1D, such as autoimmunity and genetic factors prematurity; and neonatal hypoglycemia.

Reference

Xiang AH, Wang X, Martinez MP, Page K, Buchanan TA, Feldman K. Maternal Type 1 diabetes and risk of autism in offspring. [published online June 23, 2018]. JAMA. doi:10.1001/jama.2018.7614