Very young children who have exhibited common ear and upper respiratory signs appear to have an increased risk of a subsequent diagnosis of autism or demonstrated high levels of autism traits, according to a new study using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), also known as the 'Children of the 90s' study.
ALSPAC has tracked the health of more than 14,000 children whose mothers were resident in the Avon area and were enrolled when pregnant between 1991 and 1992. The latest study on the cohort drew on data from more than 10,000 young children followed throughout their first four years. Their mothers completed three questionnaires between 18-42 months, recording the frequency of nine different signs and symptoms relating to the upper respiratory system, as well as ear and hearing problems.
The researchers correlated these with various later measures of autistic spectrum disorder, including statements of special educational provision for children diagnosed with autism by age 11; maternal reports of their child's diagnosis with autism, Asperger's syndrome, or autistic spectrum disorder at age 9; a classification as pervasive development disorder by a child psychiatrist based on a questionnaire at 91 months; responses to questionnaires from 6 months to 11 years suggesting the child had been given an autism diagnosis; and ad hoc letters from parents to the study director.
The analysis, published in BMJ Open, revealed that, overall, 177 children (139 boys and 38 girls) had a probable diagnosis of autism, while those with autism traits – including problems with speech coherence, social and communication issues, repetitive and abnormal behaviours, and sociability – were defined as the 10% of the sample with the highest trait scores.
Mouth Breathing and Ear Symptoms Associated With Autism
After adjustment for gestation, sex, parity, breast-feeding, maternal depression, education, prenatal smoking, maternal locus of control, child exposure to environmental tobacco smoke, and starting crèche by age 30 months, symptoms, including mouth breathing (all or much of the time), snoring, pulling/poking ears, ears going red, hearing being worse during a cold, and rarely listening, were significantly associated with high scores on all 15 autistic traits assessed and with diagnosed autism.
There was also evidence of associations with pus or sticky mucus discharge from the ears, especially with diagnosed autism and with poorly coherent speech.
Overall there were substantially more adjusted associations than expected by chance – 41 observed compared with 0.01 expected – and this was highly significant (p<0.001).
The researchers concluded: "Very young children exhibiting common ear and upper respiratory signs appear to have an increased risk of a subsequent diagnosis of autism or demonstrated high levels of autism traits."
Early Identification Could Improve Quality of Life
They cautioned that these signs and symptoms are "very common" in childhood, and "most children who experience them do not go on to be diagnosed with autism". However: "Early identification and treatment of ENT conditions may improve these children’s quality of life and potentially help shed light on some of the origins of autism."
Commenting to the Science Media Centre, Dr Amanda Roestorf, head of research at autism charity Autistica, 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. Of relevance to this paper, autistic children are more likely to experience problems and physical health conditions related to ear infections, auditory sensitivities and hearing problems, including conductive hearing loss, ENT problems such as snoring or sleep apnoea, and are more likely to be on antibiotics.
She added: "The study provides new insights into the potential association between early childhood ENT symptoms and autism. The longitudinal data suggest that autistic children are 3.29 times more likely to have symptoms akin to 'glue ear' or similar ear infections, and 2.18 times more likely to have hearing loss or difficulties related to cold infection. This was particularly of relevance to very young children.
"Given the issues raised in previous literature, the study findings provide a basis for considering treatment pathways for ENT problems in autistic children in general practice and secondary care."
Results Indicate a 'Possible Association'
Asked to comment by Medscape News UK, Tim Nicholls, head of influencing and research at the National Autistic Society, said: "These results should be treated with caution. They only indicate a possible association – and we know that correlation is not the same as causation. Therefore, we suggest that firm conclusions should not be drawn from it.
"Medical professionals need to be aware, however, that at least 1% of their patients are autistic. Therefore, in any consultation they should be trained and prepared to support autistic people, whether that is in being referred for a diagnosis, or with a medical issue."
Funding for the study was provided by the UK Medical Research Council, the John Templeton Foundation, and the Wellcome Trust. JG and RM are retired. YIC and SG are funded by the John Templeton Foundation. The other authors declared no conflicts of interest.