Having children at a later stage in life may be taxing on most men’s wellness, but you may not realise that this also has an impact on the child’s wellbeing. According to a new study, the findings of which appear in the journal JAMA Psychiatry, children born to fathers aged over 45 were more likely to have mental health problems and do poorly at school. These children were diagnosed with disorders such as autism, psychosis, attention deficit hyperactivity disorder (ADHD), schizophrenia and bipolar disorder more often, as well as reporting more drug abuse and suicide attempts.
Wellness writer Ian Sample points out, ‘Scientists have reported links between fathers’ age and children’s cognitive performance and health before but this study suggests the risks may be more serious than previously thought. The increased risks might be caused by genetic mutations that build up in sperm as men age.’ Study author Brian D’Onofrio, at IndianaUniversity, recalls, ‘We were shocked when we saw the comparisons.’ However, he adds that it’s not possible to be sure that older age was to blame for the problems, and other mental health experts have had reservations about the results.
Sample details, ‘Researchers at IndianaUniversity and the Karolinska Institute in Stockholm studied medical and educational records of more than 2.6 million babies born to 1.4 million men. The group amounted to nearly 90% of births in Sweden from 1973 and 2001. Using the records, the scientists added up diagnoses for psychiatric disorders and educational achievements and compared the figures for children born to fathers of different ages. The numbers told a complex story. When health and school performance were compared across all the children, and factors such as parents’ education and any history of psychiatric illness were taken into account, paternal age made little difference, except for cases of bipolar disorder, which rose with older fathers.’
However, Sample continues, ‘But the researchers went on to do another analysis. This compared the health and performance of siblings in the same families, in the hope of ruling out differences between families that may have skewed the results. This time they found a striking link between paternal age and children’s mental health and educational outcomes. According to the study, the children of fathers aged 45 and over were 3.5 times as likely to have autism, had more than twice the risk of psychotic disorders, suicidal behaviour and drug abuse, and had a 13-fold greater risk of ADHD. Fewer than 1% of children born to fathers younger than 45 had bipolar disorder, a figure that rose to about 14% in their siblings when fathers were 45 or older. In many cases, the risk of each disorder rose steadily with the father’s age.’
While Ryan Edwards, who studies the economics of health and ageing at the City University of New York, admits that the study revealed ‘some evidence that paternal age may worsen children’s psychiatric, behavioural and educational outcomes,’ he also warns that the results hinged on the scientists’ comparisons between siblings. Edwards explains, ‘In that setting, it is difficult to separate the overlapping effects of paternal age, children’s age, and birth order in a convincing way.’ Jennifer Roff, also at the City University of New York, adds, ‘I’m not saying that there is no possible genetic role for paternal age. I simply think that this could be confounded with other environmental factors like birth order. The extent of the problem will vary. I can imagine that for things like cognitive scores, this could be a larger problem than for things like schizophrenia.’