Friday, March 22, 2013

Men who have daughters after the age of 50 are 'twice as likely to have a grandchild with autism'

This is all rather improbable and the effect is small anyway.  It is unusual to have children late in life and for some such people late marriage may reflect poor mental health.  That they pass on a tendency towards poor mental health should be no surprise.  Thus it is probably poor mental health rather than age which is the causative factor

Men who have daughters when they are over 50 have almost double the risk of a grandchild being diagnosed with autism.  The risk to grandchildren from older fathers of sons is also higher than for younger dads, warn psychiatrists.

Mounting research suggests the older age of parents might be partly responsible for growing numbers of children with autism, but for the first time the risk of autism in the grandchild has been linked to the age of the grandfather at the time of his child's birth.

Findings from a new study suggest that genetic risk factors for the condition accumulate over generations.

Researchers from Britain, Sweden and Australia analysed the family and psychiatric records of almost 6,000 individuals with autism born in Sweden from 1932.  The data was compared with that from 31,000 unaffected members of the population.

The age when grandfathers on both sides had children was analysed and details of any psychiatric diagnosis considered.

The study found that autism risk in a grandchild increased the older the grandfather was when his son or daughter was born.

Men who had a daughter at the age of 50 or older were 1.79 times more likely to have a grandchild with autism than those aged 20 to 24.  Having a son at 50 or older increased a man's chance of having an autistic grandchild 1.67 times.

The findings were published in the journal JAMA Psychiatry.

In the UK, around one in 100 adults is thought to be affected by autism, mostly men, although the true rate is far higher according to some researchers.

Autism is an umbrella term for a range of developmental disorders that have a lifelong effect on someone's ability to interact socially and communicate.

Study co-author Dr Avi Reichenberg, from King's College London's Institute of Psychiatry, said:

'We tend to think in terms of the here and now when we talk about the effect of the environment on our genome. For the first time in psychiatry, we show that your father's and grandfather's lifestyle choices can affect you.

'This doesn't mean that you shouldn't have children if your father was old when he had you, because whilst the risk is increased, it is still small. However, the findings are important in understanding the complex way in which autism develops.'

Lead researcher Emma Frans, from the Karolinska Institute in Stockholm, said: 'We know from previous studies that older paternal age is a risk factor for autism

'This study goes beyond that and suggests that older grandpaternal age is also a risk factor for autism, suggesting that risk factors for autism can build up through generations.'

Autism is known to be caused by a combination of genetic and environmental factors.

Previous studies have shown that fathers aged 50 and older are more than twice as likely to have a child diagnosed with autism than younger fathers, while some research suggests older mothers may also be more at risk.

Experts think the link with paternal age could be explained by genetic errors creeping into sperm production as men get older.

The new research suggests that 'silent' mutations that leave a son or daughter unaffected may increase the risk of autism in later generations.

A combination of mounting mutations and interactions with other risk factors including persistent environmental chemicals in the body could finally cause the disorder to emerge.


Statins bad for kidneys (and other things)

Taking statins in high doses increases the risk of emergency hospital treatment for kidney damage, warn researchers.

They found patients taking high potency statins had a 34 per cent higher risk of being hospitalised for acute kidney injury, compared with those taking low doses.

Those in the high-risk group were taking 40 milligram and higher statin pills.

More than eight million adults take statins, with most taking 20-40 mg of simvastatin a day. They are the most widely prescribed drugs in the UK, with about 61 million prescriptions in England alone in 2011.

Anti-cholesterol drugs are used to reduce the risk of cardiovascular disease, with higher doses for those most at risk, and previous research has suggested they may trigger  kidney side effects.

Canadian researchers carried out an analysis comparing patients prescribed high potency statins to those who were prescribed low potency statins in seven Canadian provinces and two international databases (UK and U.S.) between 1997 and 2008.

The health records of two million people were used from the Canadian Network for Observational Drug Effect Studies for those with and without chronic kidney disease. The average age was 68 years.

The drugs Rosuvastatin at doses of 10mg or higher, atorvastatin at doses of 20mg or higher, and simvastatin at doses of 40mg or more were defined as high potency and all others as low potency.

High potency statin users were 34 per cent  more likely to be hospitalised for acute kidney injury (AKI) compared with low potency statin users in the first 120 days of treatment.

Rates were not significantly increased in patients with chronic kidney disease. This risk seemed to remain elevated for two years after starting treatment.

The researchers estimate that 1,700 patients with no previous kidney problems need to be treated with a high potency statin instead of a low potency statin in order to cause one additional hospitalisation.

But the risk could have been ‘underestimated’ they say in a report in the online medical journal

The researchers conclude that prescribing high potency statins is ‘associated with an increased rate of hospital admission with AKI compared with lower potency statins’.

The most serious adverse reaction to statins is myopathy in about one in 1,000 users, resulting in muscle pain, tenderness and weakness.

This condition can progress to rhabdomyolysis - a complete breakdown of muscle cells that can lead to kidney failure and death.

In some patients muscle weakness may persist even after stopping the drugs.

Other side-effects include cataracts, constipation or diarrhoea, headaches, loss of appetite and loss of sensation or pain in the nerve endings of the hands and feet.

The Medicines and Healthcare Regulatory Products Agency has warned about additional risks of sleep disturbances, memory loss, sexual dysfunction, depression and (very rarely) interstitial lung disease.

The risk of type 2 diabetes is raised by 12 per cent with high dose statins compared with moderate doses, according to a study.

Lead researcher Professor Colin Dormuth, of the University of British Columbia, Vancouver, said further investigation was necessary to determine how statins might be causing kidney injury.

It could be due to the increased risk of rhabdomyolysis, or  because use of statins can deplete the body's stores of CoQ10, a naturally-occurring nutrient important for energy production in cells.

Some studies suggest statins may protect against health problems, including blood clots, Alzheimer's and eye disorders, by maintaining a healthy supply of blood to the brain.

They may also cut the risk of dying from pneumonia.


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