Kids of older dads at higher risk for bipolar disorder, study suggests
02.09.2008 20:02
Health
- Source: cbc.ca
Children born to older fathers may be more likely to develop bipolar disorder, according to researchers who point to a greater risk of mutations appearing in sperm with advancing age. The latest study adds to the evidence linking increasing age to neurodevelopmental disorders such as schizophrenia, autism and bipolar disorder — a severe mood disorder that involves episodes of mania and depression. In the September issue of the Archives of General Psychiatry, Emma Frans of the Karolinska Institutet in Stockholm analyzed a Swedish national registry to identify 13,428 people with bipolar disorder who were born between 1932 and 1991. For each person with bipolar disorder, the researchers randomly matched the cases with controls who were the same sex and born the same year but did not have the disorder. After controlling for number of children, maternal age, socio-economic 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 study's authors wrote. The effect of having an older father was much stronger for early-onset bipolar disorder, which is diagnosed before age 20 and is strongly linked with genetics, the researchers said. The risks started to increase for fathers around age 40 and were strongest among those 55 or older. Children born to these oldest dads were 37 per cent more likely to develop bipolar disorder than those born to men in their 20s, the researchers found. Biological factorsAs men age, there are more opportunities for DNA copy errors to occur in sperm that result in mutations that may contribute to disorders, the study's authors said. "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 lifetime risk of developing bipolar disorder is estimated to be between one per cent and four per cent. If further research confirms the results of this study, the findings would still mean most people with older fathers won't get bipolar disorder, said Dr. Harold Pincus, vice-chair of psychiatry at Columbia University in New York. The finding "reinforces the notion that there's a strong biological component" to how older men seem more prone to having children with bipolar disorder, Pincus said. Since the prevalence of bipolar disorder is low, the slight increase in odds from advanced age should not discourage older men from becoming fathers, Frans said. Other factors besides a family history of psychotic disorders are thought to play a role in bipolar disorder, but few risk factors have been found. Factors involving mothers, including age and health, have long been thought to be most closely linked with birth defects and other abnormalities. But the new study adds to mounting evidence that paternal factors also play an important role. With files from the Associated PressStory Tools: E-MAIL | PRINT | Text Size: SMLXL | REPORT TYPO | SEND YOUR FEEDBACKRelatedInternal LinksIN DEPTH: Bipolar disorder2nd genetic code could provide clues to schizophrenia, bipolar disorderBipolar disorder diagnoses increasing: U.S. studyExternal LinksAdvancing paternal age and bipolar disorder, Archives of General Psychiatry(Note: CBC does not endorse and is not responsible for the content of external sites - links will open in new window) Health HeadlinesKids of older dads at higher risk for bipolar disorder, study suggestsChildren born to older fathers may be more likely to develop bipolar disorder, according to researchers who point to a greater risk of mutations appearing in sperm with advancing age.Fewer kids died after Ont. adopted bike helmet lawFewer young people in Ontario died of bike-related injuries after the introduction of a law requiring their use, Canadian researchers have found.Severe side effects from HPV vaccine rare: studySevere side effects of the HPV vaccine Gardasil appear to be rare, according to a study that may help calm the fears of some parents as schools prepare for another round of inoculations against one of the most common sexually transmitted infections.Web tools keep watch for drug names that look, sound alikeMixing up drug names because they look or sound alike is among the most common types of medical mistakes, and it can be deadly. 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