Both parental and grandparental age may affect odds of ASD

A new study adds to evidence that children born to older parents have higher odds of having an autism spectrum disorder (ASD). In addition, the study suggests that grandparental age might be a factor. 

Using Danish national health registries, Yu Gao and colleagues analyzed data from nearly 1.5 million children born from 1990 to 2013. Of the group, more than 27,000 had an ASD diagnosis. The researchers also examined data for fathers and mothers for whom information on grandparental age was available. 

The researchers report, “When parental age was analyzed continuously, we estimated that a five-year increase in maternal or paternal age was associated with a 9% increase in odds for ASD in children.” When they adjusted for the age of the spouse, this was attenuated to 3% for maternal age and 7% for paternal age. The highest odds were seen in women over 40 years of age and men over 50 years of age, where the odds of having a child with ASD were 50% higher than for parents between 25 and 29 years of age. 

These findings,” the researchers say, “corroborate previous studies suggesting that advanced parental age is independently associated with increased ASD risk in children.” 

In addition, study coauthor Zeyan Liew says, “We observed that children with young maternal grandparents and children with young and old paternal grandparents had higher [autism] risk compared with children of grandparents who were 25 to 29 years old at the time of the birth of the parents.” The reason for the increased risk seen in younger grandparents is unknown, but the researchers speculate that grandparents who gave birth as teenagers may have come from poorer and less supportive environments that could affect pregnancy and child health

Citations

“Association of grandparental and parental age at childbirth with autism spectrum disorder in children,” Yu Gao, Yongfu Yu, Jingyuan Xiao, Jiajun Luo, Yawei Zhang, Ying Tian, Jun Zhang, Jørn Olsen, Jiong Li, and Zeyan Liew, JAMA Network, April 15, 2020 (online). Address: Zeyan Liew, Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Yale School of Public Health, 1 Church St., New Haven, CT 06510, [email protected]. 

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“Children born to older parents have a 50 percent higher chance of autism,” Roz Plater, Healthline, April 20, 2020.