Common ear infections and nose and throat problems in children may be linked to autism, research suggests.
Experts say their large study found a link between rarely listening, mouth breathing, snoring, pulling and poking ears, ears turning red, and having worse hearing during a cold with high scores on key autism traits and with a diagnosis of autism.
They also found evidence of a link between pus or sticky mucus discharge from the ears and autism, and with inconsistent speech.
However, the team stressed that their study, published in the journal BMJ Open, does not prove that these conditions cause autism, or that children with autism are more likely to suffer from these conditions.
Previous studies have also suggested a link between these types of infections and autism.
Dr Amanda Hall, Honorary Senior Research Fellow at Bristol Medical School in the UK and Senior Lecturer in Audiology at Aston University, said: ‘I think the type of study design doesn’t allow us to say whether it has an influence causal or not.
“I think what it does is add to the pattern of findings that have been reported in the literature for a long time that children with autism have a different early history than children who are not autistic.
“The initial medical history — so ear infections and more generally — is different in autistic children than in children who don’t have autism.”
He said the team found that common ear and upper respiratory symptoms appear to be more common in children with a subsequent diagnosis of autism or high levels of autistic traits.
“However, it’s also important to note that these ENT (ear, nose, and throat) symptoms are very common in childhood, and most children who experience these signs and symptoms do not receive a diagnosis of autism,” she said.
“For example, of the group of approximately 1,700 children who snored at age 30 months, most of them (1,660 children) did not receive a subsequent diagnosis of autism.”
She said her “take-home” message for parents of autistic children is to “consult your GP or pediatrician if you have concerns about your child’s ear and hearing.”
The researchers used data from the long-term Children Of The 90s study, also known as the Avon Longitudinal Study Of Parents And Children, which has tracked children since birth.
They looked at data from more than 10,000 young children who were closely monitored during their first four years of life.
Their mothers completed three questionnaires between 18 and 42 months, recording the frequency of several signs and symptoms related to the upper respiratory system, as well as ear and hearing problems.
They also completed three questionnaires when their children were just over three, almost six and nine years old.
These were designed to identify speech coherence, social and communication problems, repetitive and abnormal behaviors and sociability – traits that are linked to autism.
Recordings showing an autism diagnosis have also been used.
Questions posed to the mothers included “Has your baby had earache?”, “Does he breathe through his mouth rather than through his nose?” and “Does he pull or scratch or touch his ears?”
Overall, 177 children in the study had a probable diagnosis of autism.
Early evidence of mouth breathing, snoring, ears pulled or poked, ears red and sore, hearing worse during a cold, and hearing infrequently, were all more commonly associated with high autism trait scores and with an autism diagnosis.
Pus or sticky discharge from the ears was also associated with autism and poor speech coherence.
Even when 10 possible environmental factors were taken into consideration, the results didn’t really change.
For example, children with pus discharge or sticky mucus from their ears were three times more likely to have autism by age 30 months, while those with hearing impairment during a cold were more than twice as likely.
The head of research at the Autistics charity, Dr Amanda Roestorf, said: ‘Over the past 30 years, there has been converging evidence to show that autistic children are likely to have more medical conditions than non-autistic children.
“This study provides new insights into the potential association between early childhood ENT symptoms and autism… Given the issues raised in the previous literature, the study findings provide a basis for considering treatment pathways for ENT problems in autistic children in general practice and secondary care”.
She said there were some potential methodological challenges to the study, including the full impact of environmental factors and relying on self-reported data provided by mothers, which may not accurately reflect symptoms.