By Laura Donnelly
9:00PM GMT 22 Jan 2014
Men warned - ‘biological’ clock means children of older fathers are more likely to suffer mental disorders
Children of older fathers are far more likely to develop mental health disorders like autism and schizophrenia, a mass study has found, with risks one third higher among men aged 45 and over.
Researchers who carried out the study on almost three million children said the findings show that it is not only women who have a “biological clock,” with the risk of genetic mutations in men increasing with age.
The international study found that children of fathers aged 45 or over had a 34 per cent higher risk of developing a mental disorder, compared with the offspring of men aged between 25 and 29.
Lead researcher, Professor John McGrath, from the University of Queensland in Australia, said the study showed the risk to older men of “a mutational time bomb”.
“For a long time, it was thought the age of the father didn’t make a difference – we were wrong,” he said. “The biological clock ticks for men.”
Professor McGrath said further research was needed before public health experts advised older men against having children but “we need to worry about it”.
“The father’s age may have implications for the health of the offspring,” he said.
“There are many benefits for having an older father – sometimes they have more stable jobs or may have had kids already and be better dads. But we are starting to pick up the risks associated with older fathers.”
More than 75,000 babies in Britain are born to fathers aged 40 and over each year, or more than one in 10 of all births.
This includes more than 6,000 born to fathers aged 50 or over. The average age of fathering a child in this country is 32.
Dr Allen Pacey, fertility expert from the University of Sheffield, said: “This is consistent with a lot of previous research but this is probably the biggest dataset yet, and it does confiirm that men are not immune to reproductive ageing. “
The senior lecturer in andrology said: “Men produce sperm throughout their lives so it’s possible to get a woman pregnant but the evidence says the health of the chidlren born to older fathers is not as good - the risks are small, but they are detectable.”
He said men needed to think about the extra risks attached with older parenthood, though health risks to the child from older motherhood are far greater.
The research, conducted by the University of Queensland, used Danish health registers to examine 2,894,688 people born in Denmark from 1955 to 2006.
The study, published in the journal JAMA Psychiatry, examined the age of mothers and fathers, and levels of mental disorders in their offspring.
However, it did not consider socio-economic factors, which previous studies suggest are likely explain to explain the higher risk amoung teenage mothers.
Researchers said it was possible that men who had their first child late in life had a higher likelihood of mental health disorders than other men.
Previous studies which adjusted for age at first fatherhood did not find an increased risk among older fathers who already children.
While men can often reproduce into old age and until they die, numerous studies have linked older fathers to negative health outcomes in their children.
A study in Iceland last year found older fathers were more likely to pass on a greater number of genetic mutations, or traits not typically found in either parent.
Professor McGrath said the latest findings suggest the sperm of older men may contain an increasing number of DNA errors.
“Mutation in the developing sperm cell may contribute to an increased risk for a surprisingly wide range of mental health disorders, including schizophrenia, autism and mental retardation,” he said. “The absolute risk of these disorders is still very low – but people should know about them.”
— Last Edited by Dixie at 2014-01-23 07:35:39 —