The siblings of patients with bipolar disorder have a higher prevalence of dyslipidemia and higher rates of ischemic stroke than do controls, results of a longitudinal cohort study suggest.
, wrote Wen-Yen Tsao, MD, of the department of psychiatry at Taipei Veterans General Hospital in Taiwan, and associates. Previous research has identified several overlapping genes between cardiometabolic diseases and mood disorders. In addition, polymorphisms of several genes tied to obesity have been associated with bipolar disorder.
In the current study, Dr. Tsao and associates analyzed the Taiwan National Health Insurance Research Database, which includes health care data from more than 99% of the Taiwanese population (J Affect Disord. 2019 Jun 15. doi: 10.1016/j.jad.2019.04.094). Adults born before 1990 who had no psychiatric disorders, a sibling with bipolar disorder, and a metabolic disorder were enrolled as the study cohort. A control group was identified randomly. By way of ICD-9-CM codes, people with type 2 diabetes, hypertension, dyslipidemia, and obesity were identified in both cohorts. The investigators followed the metabolic status of 7,225 unaffected siblings of bipolar disorder patients and 28,900 controls from 1996 to 2011.
Dr. Tsao and associates found that the family members who had siblings with bipolar disorder had a higher prevalence of dyslipidemia (5.4% vs. 4.5%; P = .001), compared with controls. The group with siblings with bipolar disorder also were diagnosed with type 2 diabetes at a younger age (34.81 vs. 37.22; P = .024), and had a higher prevalence of any stroke (1.5 vs. 1.1%; P = .007) and ischemic stroke (0.7% vs. 0.4%, P = .001), compared with controls.
A subanalysis showed that the higher risk of any stroke (odds ratio, 1.38; 95% confidence interval, 1.02-1.85) and ischemic stroke (OR, 2.43; 95% CI, 1.60-3.70) pertained only to male siblings. That gender-specific finding might be attributed to differences in plasma triglyceride clearance between men and women, the researchers wrote.
The findings might not be generalizable to other populations, the investigators noted. In addition, they said, the prevalence of cardiometabolic disease in the groups studied might be underestimated.
“Our results may motivate additional studies to evaluate genetic factors, psychosocial factors, and other pathophysiology of bipolar disorder,” they wrote.
The study was funded by Taiwan’s Ministry of Science and Technology, and Taipei Veterans General Hospital. The researchers cited no conflicts of interest.