WASHINGTON, D.C.: A massive study of more than two million people in Sweden has found that those with older dads faced a higher risk of psychiatric problems, autism and attention disorders, researchers said on Wednesday (Thursday in Manila).
Compared to people whose fathers were between the ages of 20 and 24 at the time of their birth, those with dads 45 or older were 25 times more likely to have bipolar disorder, said the findings in JAMA Psychiatry, a journal of the American Medical Association.
The study found people born to older dads also were 13 times more likely to have attention deficit hyperactivity disorder.
The research adds to a growing body of science on the negative effects of delayed procreation in men, an area that has traditionally focused on the risks to women and their offspring.
“We were shocked by the findings,” said Brian D’Onofrio, lead author and associate professor in the Department of Psychological and Brain Sciences in the College of Arts and Sciences at Indiana University, Bloomington.
“The specific associations with paternal age were much, much larger than in previous studies,” said D’Onofrio, who collaborated with researchers at Karolinska Institute in Stockholm.
The size of the data set—2.6 million people—accounted for every person born in Sweden from 1973 until 2001.