Brett Smith for redOrbit.com – Your Universe Online
While several recent studies on the risk of a child developing an autism spectrum disorder (ASD) have focused on paternal age or even the age of the grandfather, a new Sweden-based study has found that risk for ASD increases with the age of both parents – but particularly for would-be mothers.
The study, published in the International Journal of Epidemiology, revealed that ASD risk with parental age increased linearly for older fathers, while risk increased rapidly for women after the age of 30.
“The open question at hand really is, what biological mechanisms underlie these age effects?” said Brian K. Lee, an assistant professor in the Drexel University School of Public Health, in a recent statement.
To reach their conclusion, the researchers reviewed a large population database sample of nearly 420,000 children born in Sweden between 1984 and 2003. The study team considered several possible confounding factors that could fluctuate with parental age and also affect risk, including family income and each parent’s psychiatric background. The study also used a detailed case-finding strategy, to determine more ASD cases than other research studies might, based on all routes to care in a socialized healthcare system.
The researchers said their objective was to analyze the effect of parental age in greater detail by investigating possible differing risks of ASD with and without mental disability – one of the most substantial coinciding diagnoses with ASD, with a substantial effect on well-being. The researcher said their study was the first population-based study with an ASD sample sufficiently large enough to analyze ASD risk in populations of children regardless of intellectual disability.
“When considering risk factors, we can’t necessarily lump all ASD cases together, even though they fall under a broad umbrella of autism,” Lee said. “We need to keep an open mind in case intellectual disability might be a marker of a different underlying mechanism.”
Upon discovering that ASD with intellectual disability had a stronger connection with older parents than ASD without intellectual disability, the study team said their work supports further investigation of possible different causes.
Lee mentioned that, even though age effects are critical indicators of risk at the population level, they aren’t very considerable for a couple’s family planning due to the fact that overall risk remains low.
“The absolute risk of having a child with ASD is still approximately 1 in 100 in the overall sample, and less than 2 in 100 even for mothers up to age 45,” Lee said.
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