Risk of Autism greater in older fathers

September 6, 2006

Brussels, 05 Sep 2006

A joint US-UK-Israeli study has shown for the first time that older male parents have an increased risk of autistic children. A second study indicates that autistic children may benefit from probiotics in the treatment of the condition. The first study followed 132,1 Israeli children born over six years in the 1980s. They found that while maternal age at birth had a negligible effect on the incidence of autism spectrum disorder (ASD), the paternal age did.

Israeli children were particularly useful for this study because, 'Virtually all men and about three quarters of women in this cohort underwent draft board assessment at age 17 years,' according to the paper. This means that there was a reliable clinical diagnosis of ASD.

'There was a significant monotonic association between advancing paternal age and risk of ASD,' reads the report. The study split the fathers into three groups, aged 15-29, aged 30-39 and 40-49.

The 15-29 group was found to have six ASD children in every 10,000. The 30-39 group found a slightly raised incidence of nine ASD children in every 10,000. However, for the 40-49 age group, the incidence of ASD rose dramatically, with 32 ASD children in every 10,000 - 5.75 times the incidence in the 15-29 age group.

Researcher Dr Abraham Reichenberg, from Sinai School of Medicine in New York, and the Institute of Psychiatry spoke to the Press Association. 'This research adds to our knowledge that men also have a biological clock when it comes to reproducing.'

A fourth group, of fathers aged 50+, had a very small sample, but was thought to have a yet higher incidence. 'The sample size for the over-50s was small so we added it to the results for fathers aged over 40, but our research suggests that very old fathers have around nine times the risk. The research shows a linear effect - with every 10 years, the risk doubles,' he said.

In a second, preliminary, study, researchers from the University of Reading in the UK examined the possibility of treating ASD with probiotics - 'beneficial' bacteria.

Autism sufferers regularly suffer stomach complaints. The team examined stool samples from ASD and non-ASD children aged between four and eight years old. They found high levels of the bacteria Clostridium in the samples of ASD children.

'Whatever is going on there, [it] is not doing these children any good, and I think almost certainly explains their gastro problems,' said Professor Glenn Gibson to the British Association Festival of Science in Norwich, UK, reported in the Guardian newspaper.

The study was confounded because parents noticed improvements in their children when given the probiotic, but not the placebo. 'Some of the parents worked out that their child was on the [probiotic] and didn't want to move on to the placebo because they were seeing some positive results,' he said. This caused the parents to drop out of the study.

These two results paint a complicated picture for ASD. Recent research has also pointed to a genetic basis for the condition. Together, these results point to a varied and complex basis for the disease, which is both debilitating and mysterious.

For further information, read the study into ASD and paternal age:

Go to the British Association Festival of Science:

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