Wednesday, September 06, 2006

OLDER men are far more likely to father autistic children

Since autism seems to be linked to high intelligence, these results may mean that smart older guys tend to have more children than dumb older guys

A study involving more than 100,000 children found that those born to fathers aged 40 and over were nearly six times more likely to suffer from autism and related disorders than those with a father under 30. Scientists from the Institute of Psychiatry at King's College, London and Mount Sinai School of Medicine in New York, said that their research supported the theory that men also have a "biological clock" when it comes to producing healthy babies.

They described the findings as "the first convincing evidence that advanced paternal age is a risk factor for autism spectrum disorder". However the authors could not find a link between a mother's advancing age and autism.

The exact causes of autism remain unknown, but cases of it and related conditions such as Asperger's syndrome - known collectively as autism spectrum disorders (ASDs) - have increased tenfold in the past two decades. They now affect the lives of more than half a million families in Britain. A recent study suggested that the rate could be as high as 116 ASD cases per 10,000 children...

The latest study, published in the Archives of General Psychiatry, analysed 132,271 Jewish children born during the 1980s in Israel. The researchers found that, if the father was aged 15 to 29 when the child was born, the risk of autism was 6 in every 10,000 children. If the father was 30 to 39, then 9 in 10,000 children suffered autism (1.6 times higher), going up to 32 in 10,000 (5.75 times higher) for fathers aged 40 to 49. The risk was even higher for older fathers.

"This research adds to our knowledge that men also have a biological clock when it comes to reproducing," Dr Reichenberg said. "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 ten years, the risk doubles."

The researchers emphasised that the results related to autism and could not necessarily be generalised to apply to related disorders such as Asperger's syndrome. But they added: "This data suggests a significant association between advancing paternal age and risk of ASD."

They said that there were several genetic factors which could be at play, including spontaneous mutations in sperm-producing cells, or discrepancies in how genes are expressed.

Although the fact that all the children were Jewish was a limitation of the study, Dr Reichenberg did not believe it affected the results. More research was needed to see if the findings were replicated across other racial and ethnic backgrounds.

More here

A weighty problem: Neither Australia nor the world can tax itself thin

Robert Malthus, call your office. Contrary to your 1798 prediction that the world would face starvation as population outstripped food supply, the greatest consumption problem of the 21st century is that the world is eating too much. Around the world, humans are getting fatter and experts are tipping all manner of health crises as a result, from an epidemic of diabetes to the possibility that today's young may be the first generation in recent history not to live longer than their elders.

Making the problem particularly difficult for Australia is that ours is thought to be the only country in the world where the childhood obesity rate has overtaken that of adults. At the International Congress on Obesity presently being held in Sydney, experts from around the world have gathered to discuss what to do about the problem. But too many solutions on offer focus on simplistic state action such as taxes on junk food, regulation of fat content and bans on advertising.

At the heart of the matter is choice and what people choose to put in their bodies. Given that obesity rates tend to increase as one moves down the socio-economic ladder, calls for regulation of how people eat have more than a whiff of elitism about them. But there is little evidence that taxing something as vaguely defined as "junk food" would steer consumption in more healthy directions. Processed food and fast food are all more expensive ways to feed a family than some fresh vegetables, pasta or meat quickly and simply prepared; there is more to people's food choices than economics.

Rather than micromanaging menus, governments would do far better to encourage healthy eating through public awareness campaigns demonstrating that eating healthily leaves one with less fat on the waistline, more money in the pocket and more years of life. Demonising weight problems only contributes to eating disorders at the other end of the spectrum. Schools can play a part in ensuring that students are physically active every day, not just for a couple of hours a week. Obese people and parents with overweight kids require positive encouragement to help them change, not the punitive cudgel of taxes and regulations.


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