BRISTOL, United Kingdom — Could common childhood illnesses actually be a warning sign that a toddler has autism? A new study finds that young children experiencing recurring ear and upper respiratory problems may be at greater risk of receiving an autism diagnosis later on. The findings could shed more light on the origins of the neurodevelopmental disorder.
There is no single cause for autism. Instead, scientists believe it is a combination of genetic, environmental, and biological factors. Autism is called a spectrum disorder because it affects individuals in different ways and to varying degrees. Previous research into the origins of autism has pointed out a relationship between the condition and ear, nose, and throat (ENT) issues such as ear infections, “glue ear,” and sleep-disordered breathing.
However, the evidence pointing to a possible relationship could have been biased since it came from personal health records. For example, parents of children with suspected autism may be more likely to seek medical care than parents without autistic children.
The current study sought to remove bias and decide once and for all if there is a link between the two conditions. The researchers took health information from people who enrolled in a study of children born in the 1990s. This long-term study has been tracking the health of over 14,000 children and their parents since that time.
Study authors examined data on more than 10,000 young children in their first four years of life. Their mothers filled out three questionnaires when their child was 18, 30, and 42 months — including having them write down how often they experienced nine symptoms related to the ear, nose, throat, and hearing problems. They completed another set of three questionnaires when their children were three, nearly six, and nine years-old. The surveys asked about any problems with speech, social and communication issues, repetitive and abnormal behaviors, and sociability — all traits connected to autism. Researchers also collected official autism diagnoses from educational records, parents, and other sources.
Certain ear problems have a strong connection to autism
A total of 177 children received a diagnosis or likely diagnosis of autism. Results show a link in preschool-aged children who breathed through their mouth, snored, pulled or poked their ears, had reddened and sore ears, and had worse hearing during a cold with traits related to autism. These children scored high on four autism traits and were more likely to receive an autism diagnosis. Additionally, having pus or sticky discharge from the ears also displayed a link to autism onset and poor coherent speech.
The signs of possible autism are most prevalent when a child is between 30 and 42 months. For example, children scoring high for autistic traits at 30 months had more ENT signs. Those with discharge in their ears were three times more likely to have autism, while those with impaired hearing were twice as likely. Children who did not react to nearby noise were six more likely to have autism at this age.
Despite the multiple associations between ENT symptoms and autism, the authors warn that this doesn’t mean every child who experiences ear or nose problems is autistic. They focused the associations on a small group of children suspected of autism. Of the 1,700 children who snored at 30 months, 1,660 did not receive an autism diagnosis.
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There are other study limitations to consider, including losing track of some children’s lack of response or follow-up. There’s also the lack of diversity in these studies, which was a widespread issue in the 90s, meaning these results cannot be generalized to people who are not White. Additionally, not every child received an official diagnosis. Instead, the authors calculated the probability of a diagnosis based on the sources and health records available.
According to the authors, who were based in the United Kingdom, the study cannot definitively prove that ENT conditions cause autism since other influencing factors could be at play.
“One possibility, for example, could be the consequence of the increased prevalence of minor physical anomalies in individuals with autism, including anatomical differences in the structure and/or positioning of the ear, with such differences in ear morphology increasing the risk of ENT conditions,” the study authors conclude in a media release.
The study is published in the journal BMJ Open.
