History of Depression Remains a Risk Factor for Heart Disease after Accounting for Other Contributing Factors among Twin Veterans
Major depression is a well established risk factor for cardiovascular disease. Increasing evidence also suggests common genetic vulnerability partly explains the association between ischemic heart disease (IHD) and depression. This prospective twin study sought to determine if depression contributes to incident heart disease after accounting for genetic, behavioral, and medical factors associated with both conditions. Using previously collected data from the Vietnam Era Twin Registry and data from the prospective Vietnam Era Study of Aging (VETSA), investigators identified 1,159 male twins who served in the U.S. military during the Vietnam era (1965-1975). The majority of Veterans in this study did not serve in combat or in Vietnam.
Findings show that a history of depression remained a risk factor for incident heart disease even after adjusting for numerous covariates including: sociodemographics, co-occurring psychopathology, smoking, obesity, diabetes, hypertension, and social isolation. Moreover, twins with both high genetic and phenotypic expression of depression were at greatest risk of IHD. Among depressed twins, 15% had angina, 10% had MI, and 8% had cardiac procedures compared to non-depressed twins who had 5% angina, 4.6% MI, and 4.9% cardiac procedures, respectively. Results also show that twins with hypertension and twins with diabetes were more likely to have IHD, as were twins who reported no social support. Age, race, education, and marital status were not associated with IHD status. The authors suggest further research is warranted to ascertain what known risk factors for IHD (e.g. smoking) share common genetic and environmental variance with major depression.
Xian H, Scherrer J, Franz C, et al. Genetic vulnerability and phenotypic expression of depression and risk for ischemic heart disease in the Vietnam Era Twin Study of Aging. Psychosomatic Medicine May 2010;72(4):370-75.
Dr. Scherrer is supported by an HSR&D Career Development Award. Drs. Xian and Scherrer are part of the St. Louis VAMC.