Study links bipolar disorder with older fathers

Men, here is yet another reason why you shouldn't delay starting a family on the pretext of a career -- older fathers are more likely to have children with
bipolar disorder, a new study has revealed.

And, according to the study, the risk of bipolar disorder -- a severe mood disorder involving episodes of mania and depression -- goes up when men are older than 29 before they start their family, and is highest if they are over 55.

In fact, researchers in Sweden have found that unlike women who are born with all their eggs, men make sperm throughout their adult life and the process of making semen, which involves copying DNA, is prone to error as men age.

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

"(However), 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," lead researcher Emma Frans was quoted by the 'Archives of General Psychiatry' journal as saying.

For the study, they identified 13,428 patients in Swedish registers with a diagnosis of bipolar disorder. For each one, they randomly selected five controls who're the same sex and born the same year but did not have bipolar disorder.

After controlling for other factors like age of the individual's mother, number of siblings and family history of mental health problems, the researchers found a clear link between risk of bipolar disorder and the father's age.

The older an individual's father, the more likely he or she was to have bipolar disorder, the study found. "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," Frans wrote in the latest issue of the journal.