Older fathers are at an increased risk of having children with bipolar disorder, a new study from Sweden's largest centre for medical training and research has suggested.

Published in the Archives of General Psychiatry and led by staff from the Karolinska Institute in Stockholm, the study pinpointed 13,428 people with the condition.

For each one, they then randomly selected five control participants who were the same age and gender but did not have bipolar disorder.

"After controlling for parity, 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," the researcher stated.

The risk of developing bipolar disorder may be linked to ageing sperm in men, the scientists from the medical university suggest, noting that the production process is prone to error as males age.

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