Causes of decreased life expectancy over the life span in bipolar disorder

Abstract

Background: Accelerated aging has been proposed as a mechanism explaining the increased prevalence of comorbid general medical illnesses in bipolar disorder.

Aims: To test the hypothesis that lost life years due to natural causes starts in early and mid-adulthood, supporting the hypothesis of accelerated aging.

Methods: Using individual data from nationwide registers of patient with a diagnosis of bipolar disorder we calculated remaining life expectancies before age 90 years for values of age 15, 25, 35…75 years among all individuals alive in year 2000. Further, we estimated the reduction in life expectancy due to natural causes (physical illnesses) and unnatural causes (suicide and accidents) in relation to age.

Results: A total of 22,635 patients with bipolar disorder were included in the study in addition to data from the entire Danish general population of 5.4 million people. At age 15 years, remaining life expectancy before age 90 years was decreased 12.7 and 8.9 life years, respectively, for men and women with bipolar disorder. For 15-year old boys with bipolar disorder, natural causes accounted for 58% of all lost life years and for 15-year old girls, natural causes accounted for 67% increasing to 74% and 80% for 45-year old men and women, respectively.

Limitations: Data concern patients who get contact to hospital psychiatry only.

Conclusions: Natural causes of death is the most prevalent reason for lost life years already from adolescence and increases substantially during early and mid-adulthood, in this way supporting the hypothesis of accelerated aging. Early intervention in bipolar disorder should not only focus on improving outcome of the bipolar disorder but also on decreasing the risk of comorbid general medical illnesses.

Keywords: Bipolar disorder; Comorbid general medical illness; Life expectancy; Mania; Mortality; Suicide.