Autism figures higher than thought

Autism affects many more people than has previously been recognised, but not because of any connection with the triple MMR vaccine, according to a new review of evidence to be published today.

The review, led by scientists at the Institute of Child Health at Great Ormond Street Hospital, found that two recent studies both agreed that around six children in every 1,000 are affected by "autism spectrum disorders" (ASDs). This is a higher figure than was expected by experts.

However, the review announced by the Medical Research Council also found that there was still no evidence to suggest that this was in any way connected to the use of the triple mumps, measles and rubella vaccine (MMR).

"We conclude that the current epidemiological evidence does not support the the proposed link of MMR to ASDs," the review finds. "Our conclusions are consistent with the findings of other expert groups that have reviewed this question." Neither does current evidence support conclusively any link with gastrointestinal disorders, or that diet could control the condition, says the review. Properly controlled studies have been conducted on too few children to come to a conclusion in either case, it says.

It finds instead that diagnosis of the disorders has greatly improved, and that autism has always been more common than was generally recognised, said Dr Carol Dezateux, consultant paediatrician and epidemiologist at the Institute of Child Health and leader of the review. "Ideas about autism have changed, and our identification of it has changed. It is not a true rise." In the past, she says, only one form of autism was recognised - the "classical"-version in which children are withdrawn, aloof, unable to communicate and have characteristic, repetitive or obsessive behaviours.

"That is only one end of the spectrum," she said. "We recognise now more and more that the pattern of severity differs between children.

"At the other end of the scale there might be a child who, for example, does not make normal eye contact with other children and does not communicate with them nonverbally, and whose language is fluent but inappropriate, so that it, too, is about communication."

The review also concludes that virtually nothing is known about the prospects for later life of children with autism. "It really is not known what life holds for them," said Dr Dezateux. "It is a life-long condition, but there is only broad research that suggests that if you are of normal intelligence you may be able to hold down a job in later life, but that you might not be a very happy adult."