People who experience depressive symptoms by midlife may end up with long-lasting physical health consequences, including diabetes, sleep apnea and hypertension, a new study suggests.

The research, published Jan. 12 in Psychological Medicine, took a longitudinal approach to the topic by studying 787 male twin veterans from the Vietnam Era Twin Study of Aging, which examines both genetic and environmental factors on cognitive aging starting in midlife. 

The investigators on this particular project were looking into “understanding more about how mental health affects multiple processes across the lifespan, including physical health trajectories,” according to Hillary Ditmars, a clinical psychology Ph.D. student at Boston University and an author of the study. By focusing on twins, the researchers were able to disentangle the different genetic and environmental influences on a given trait, Ditmars said.

The study noted depression symptoms among the participants at the baseline age, which was an average of about 41 years old. It then looked at the later onset of eight different cardiometabolic conditions — atrial fibrillation, diabetes, erectile dysfunction, hypercholesterolemia, hypertension, myocardial infarction, sleep apnea and stroke — which were assessed via self-reported doctor diagnoses 27 years later.

Higher levels of depression symptoms were longitudinally associated with higher incidence rates of diabetes (22.5%), erectile dysfunction (22.9%), hypercholesterolemia (57.1%), hypertension (53.6%) and sleep apnea (20.5%) among the surveyed population.

Because this study is observational, the results found don’t necessarily establish a causal relationship between depression symptoms and poor cardiometabolic health, but they do “underscore the importance of talking to your health care provider about your mental health history,” Ditmars said.

But given the 27-year length of the follow-up period, Ditmars noted that the findings do suggest that the association between mental health symptoms and later physical health problems persists over time, regardless of whether that relationship is causal.

Ditmars added that the results show that there needs to be greater awareness of the connections between mental and physical health, especially in a clinical environment, and that more can be done to facilitate that recognition.

“I think awareness is growing across many disciplines, as well as in society more broadly, that mental and physical health are connected — or that, in other words, mental health is health,” Ditmars said. “I think interdisciplinary collaboration and efforts to reduce stigma surrounding mental health are both critical to underscore the connections between mental and physical health.”

Research into the connection between mental and physical health is ongoing, Ditmars said, with the next step including searching for a better understanding of the mechanisms that drive the link between depression symptoms and cardiometabolic health. 

Future research may also look more directly at hypothesized mediators of the observed associations in order to better grasp “the pathways by which depression could be leading to these physical health outcomes,” Ditmars added.

The article, “Associations between depression and cardiometabolic health: A 27-year longitudinal study,” was published on Jan. 12, 2021 in Psychological Medicine. It was authored by Hilary Ditmars, Rosemary Toomey, Ruth McKenzie, Kristy Cuthbert, Richard Vandiver, and Michael Lyons, all of Boston University; Mark Logue of the VA Boston Healthcare System; Carl Franz, Matthew Panizzon, Graham Eglit, Jeremy Elman, Mark Sanderson-Comino, Lisa Tyler, Christine Fennema-Notestine, Richard Hauger, Amy Jak, Nathan Whitsel, Chandra Reynolds, Anders Dale, and William Kremen, all of the University of California; Ole Andreassen of the KG Jebsen Centre for Psychosis Research; Nathan Gillespie and Michael Neale of Virginia Commonwealth University; Xin Tu of the VA San Diego Healthcare System, and Hong Xian of Saint Louis University College for Public Health and Social Justice.