Washington DC: Living with bipolar disorder, a serious mental condition that can produce both manic and depressive mood swings, can be difficult.
It also comes with a higher risk of dying early. Now, a study puts into perspective just how large that risk is, and how it compares with other factors that can shorten life.
In two different groups, people with bipolar disorder were four to six times more likely as people without the condition to die prematurely, the study finds.
By contrast, people who had ever smoked were about twice as likely to die prematurely than those who had never smoked - whether or not they had bipolar disorder.
A team from the University of Michigan, home to one of the world's largest longterm studies of people with bipolar disorder, reports their findings in the journal Psychiatry Research.
The stark difference in mortality, and the differences in health and lifestyle that likely contributed to it, should prompt more efforts at preventing early deaths, say the researchers.
"Bipolar disorder has long been seen as a risk factor for mortality, but always through a lens of other common causes of death," said Anastasia Yocum, Ph.D., lead author of the study and data manager of the research program at the Heinz C. Prechter Bipolar Research Program.
"We wanted to look at it by itself in comparison with conditions and lifestyle behaviors that are also linked to higher rates of premature death."
Two large data sources yield similar findings
Yocum and her colleagues, including Prechter Program director Melvin McInnis, M.D., started by looking at deaths and related factors among 1,128 people who had volunteered for the program's longterm study of people with and without bipolar disorder.
They found that all but 2 of the 56 deaths since the study began in 2006 were from the group of 847 people in the study who had bipolar disorder.
With statistical adjustments, their analysis shows that having a diagnosis of bipolar disorder made someone six times more likely to die during a 10-year period than people taking part in the same study who did not have bipolar disorder.
By comparison, study participants who had ever smoked or were over age 60 were more than twice as likely to die in that same time as people who never smoked or were under 60, regardless of bipolar status.
The researchers then turned to another source of data to see if they could find the same effect.
They analyzed years' worth of anonymous patient records from more than 18,000 people who get their primary care through Michigan Medicine, U-M's academic medical center.
Among this group, people with bipolar disorder were four times as likely to die during the study period than those with no record of bipolar disorder.
The team studied records from more than 10,700 people with bipolar disorder and a comparison group of just over 7,800 people without any psychiatric disorder.
The only factor associated with an even higher chance of dying during the study period in this pool of people was high blood pressure.
Those who had hypertension were five times more likely to die than those with normal blood pressure, no matter whether they had bipolar disorder or not.
By contrast, smokers were twice as likely to die as never-smokers in this sample, and those over age 60 were three times as likely to die, both regardless of bipolar status.
"To our major surprise, in both samples we found that having bipolar disorder is far more of a risk for premature death than smoking," said McInnis, a professor of psychiatry at the U-M Medical School.
He hopes the findings will spur more action in the medical and public health communities to address the many factors that contribute to this extra-high risk of death in people with bipolar disorder.
"Over the years there have been all kinds of programs that have been implemented for smoking prevention and cardiovascular disease awareness, but never a campaign on that scale for mental health," he said, noting that about 4% of Americans live with bipolar disorder while about 11.5% of Americans smoke.
Other differences between groups
Yocum and McInnis note that people with bipolar disorder in both groups were much more likely than the people without bipolar disorder to have ever smoked, consistent with past studies.
Nearly half (47%) of the U-M patients with bipolar disorder had a history of smoking, as did 31% of the Prechter participants with bipolar disorder.
By comparison, smoking among those without bipolar disorder stood at 29% of the U-M patients and 8% of the Prechter participants.
