THE latest Australian data on autism contradicts research indicating that new cases have levelled off in the UK, according to an expert.
Local rates appear to be in line with recent US data, which found that one in 88 eight-year-olds had been diagnosed with autism spectrum disorder.However, UK researchers examined the General Practice Research Database (GPRD), which contains three million records, and found the annual prevalence and incidence of autism did not materially change between 2004 and 2010 for boys or girls.
The UK prevalence of about four per 1000 children was substantially lower than the equivalent US figure of about 11 per 1000 children in 2008.
Previous UK research, based on the same database, showed that the cumulative incidence of autism had increased continuously by a factor of five between 1988 and 1995.
Professor Cheryl Dissanayake, of the Olga Tennison Autism Research Centre at La Trobe University, Melbourne, said she was surprised by the results.
A 2010 study she was involved in found one case per 119 children, which “confirmed what the US Centers for Disease Control was saying at that time”, she said.
She said two new Australian data sets were also set to match recent parent-reported prevalence at school age of around one in 52 children.
Professor Jon Jureidini, head of psychological medicine at the Women and Children’s Hospital, Adelaide, said evidence that the epidemic of diagnosis was not growing would be positive.
“I would prefer to move away from diagnosis towards more of an attempt to understand what’s happening in an individual, and I don’t think that happens enough in Australia,” he said.
BMJ Open 2013; online 16 Oct