Children of Older Fathers at Risk for Bipolar Disorder

(HealthDay News) -- The older the father, the greater his child's risk for bipolar disorder.

That's the conclusion of a new study by Swedish researchers who compared 13,428 people with bipolar disorder to more than 67,000 people without the condition.

"After controlling for parity (number of children), maternal age, socioeconomic status and family history of psychotic disorders, the offspring of men 55 years and older were 1.37 times more likely to be diagnosed as having bipolar disorder than the offspring of men aged 20 to 24 years," wrote Emma M. Frans, of the Karolinska Institute in Stockholm, and colleagues.

Children of older mothers also had an increased risk, but the risk was less pronounced than that associated with older fathers. In cases of early onset bipolar disorder (diagnosed before age 20), the effect of the father's age was much stronger, while the mother's age had no effect, the study found.

"Personality of older fathers has been suggested to explain the association between mental disorders and advancing paternal age. However, the mental disorders associated with increasing paternal age are under considerable genetic influence," the study authors wrote.

This suggests a genetic link between the advancing age of the father and bipolar and other disorders among children, the researchers said.

"As men age, successive germ cell replications occur, and de novo (new, not passed from parent to offspring) mutations accumulate monotonously as a result of DNA copy errors," the researchers noted.

"Women are born with their full supply of eggs that have gone through only 23 replications, a number that does not change as they age. Therefore, DNA copy errors should not increase in number with maternal age. Consistent with this notion, we found smaller effects of increased maternal age on the risk of bipolar disorder in the offspring."

The study was published the September issue of the journal Archives of General Psychiatry.

Bipolar disorder is a common, severe mood disorder involving episodes of mania and depression. Other than a family history of psychotic disorders, few risk factors for the condition have been identified, according to background information in the article.

More information
The U.S. National Institute of Mental Health has more about bipolar disorder.

Study: Kids of older dads have higher bipolar risk

CHICAGO, Illinois (AP) -- Children born to older fathers face a greater chance of developing bipolar disorder, according to one of the largest studies linking mental illness with advanced paternal age.

Research has connected schizophrenia and autism with older dads, and a Danish study published last year added bipolar disorder to the list. The new study led by researchers at Sweden's Karolinska Institute strengthens the evidence.

The leading theory is that older men's sperm may be more likely to develop mutations. Even so, the odds of a person becoming bipolar are so low that the study's authors said it shouldn't dissuade older men from becoming fathers.

Researchers analyzed Swedish national registry data from more than 80,000 people, including 13,428 with bipolar disorder who were born between 1932 and 1991.

The risks started increasing around age 40 but were strongest among those 55 and older. Children with these dads were 37 percent more likely to develop bipolar disorder than those born to men in their 20s.

They also faced more than double the risk of developing bipolar disorder before age 20. Scientists call that early onset disease, and although they have long known that bipolar disorder tends to run in families, early onset disease has been thought to be most strongly linked with genetics. Continue Reading >>