New York, Aug 11 (IANS): Common gastrointestinal (GI) symptoms such as diarrhoea, constipation and bloating are linked to troubling sleep problems, self-harm and physical complaints in pre-school children especially those with with autism, say researchers.

According to the new study, published in the journal Autism Research, these GI symptoms are much more common and potentially disruptive in young kids with autism.

"This study highlights the link between GI symptoms and some problematic behaviours we see in preschool-aged children," said study researcher Bibiana Restrepo from the University of California in the US.

Gastrointestinal concerns are frequently reported by parents of children with autism spectrum disorder (ASD).

For the results, the research team evaluated the presence of GI symptoms in preschool-aged children with and without autism.

The study included 255 children with ASD between two and 3.5 years of age and 129 typically developing children in the same age group.

Paediatricians specialising in autism interviewed caregivers during the children's medical evaluation.

They asked the parents how often their children experienced GI symptoms such as difficulty swallowing, abdominal pain, bloating, diarrhoea, constipation, painful stooling, vomiting, difficulty swallowing, blood in stool and blood in vomit.

The researchers grouped children in two categories: those who experienced one or more GI symptom and those who never or rarely had GI symptoms in the last three months.

They compared the children in the two groups on measures of developmental, behavioural and adaptive functioning.

The study found that preschool-aged children with ASD were 2.7 times more likely to experience GI symptoms than their typically developing peers.

In fact, almost 50 per cent of children with ASD reported frequent GI symptoms - compared to 18 per cent of children with typical development.

The findings showed that around 30 per cent of the children with ASD experienced multiple GI symptoms.

Multiple GI symptoms were associated with increased challenges with sleep and attention, as well as problem behaviours related to self-harm, aggression and restricted or repetitive behaviour in both autistic and typically developing children.

The severity of these problems was higher in children with autism.

"Problem behaviours may be an expression of GI discomfort in preschool-aged children," the study authors wrote.

"GI symptoms are often treatable, so it is important to recognize how common they are in children with autism. Treating their GI symptoms could potentially provide some relief to the kids and their parents," they noted.