Size At Birth Affects Risk Of Mental Health Conditions

Above-average sized babies have a higher risk of autism and a lower risk of schizophrenia, while the opposite is true for below-average sized babies.

AsianScientist (Sep. 23, 2014) – A child’s birth weight and length can partially predict the likelihood of being diagnosed with mental health conditions such as autism and schizophrenia later in life, according to a paper published in the Proceedings of the Royal Society B.

The research, led by University of Melbourne researcher Dr. Sean Byars while based at the Copenhagen Center for Social Evolution, 

analysed medical records of 1.75 million Danish births and suggested that genetic imprints established at conception could influence both size at birth and mental health during childhood and adolescence. 

Dr. Byars said the findings were consistent with evolutionary theory, which predicts that disruptions to specialised genes may have effects on fetal growth and neurodevelopment. Birth size was used to capture the later risk of autism and schizophrenia. Very small babies had increased risks for most mental disorders.

“We found that heavier and longer babies had enhanced risk for autism and reduced risk for schizophrenia, while the opposite held for lighter and shorter babies,” he said.
“For example, Danish newborns are on average 52 centimetres long and being born at 54 centimetres increases autism risk by 20 percent. However, these are relative risks and these disorders remain rare.” 

“Risk patterns are opposite in smaller newborns, who have higher risk for schizophrenia and lower risks for autism,” Dr. Byars said.

Dr. Byars said these findings will contribute to a more comprehensive understanding of the factors that make people vulnerable to such conditions.

The article can be found at: Byars et al. (2014) Opposite Risk Patterns for Autism and Schizophrenia are Associated with Normal Variation in Birth Size: Phenotypic Support for Hypothesized Diametric Gene-dosage Effects.


Source: University of Melbourne; Photo: Dave Herholz/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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