Obesity in PTSD patients accounts for increased risk of type 2 diabetes mellitus

Saint Louis University research finds post-traumatic stress disorder does not directly lead to type 2 diabetes mellitus (T2DM), instead obesity in PTSD patients accounts for the increased risk.

The study, "The Role of Obesity in the Association Between Posttraumatic Stress Disorder and Incident Diabetes" was published Aug. 8 in JAMA Psychiatry.

Post-traumatic stress disorder is associated with risk factors for type 2 diabetes, including poor diet, lack of exercise, alcohol abuse and obesity. The risk factors may interact with hypothalamic-pituitary-adrenal changes to increase the risk of type 2 diabetes.

Numerous studies over the past two decades have indicated patients with PTSD have an increased risk of developing type 2 diabetes compared to those without PTSD or without a mental health condition, said study author Jeffrey Scherrer, Ph.D., professor of family and community medicine at Saint Louis University.

"While these studies have simultaneously controlled for obesity and other diabetes risk factors, none have teased out the independent effect of obesity on the PTSD to incident diabetes association," Scherrer said.

The current study by Scherrer and his co-authors was designed to determine if obesity, which is more common in patients with PTSD, accounted for the increased risk of diabetes.

The retrospective cohort study used medical record data collected between 2008-2015 from 2,204 Veterans Health Affairs patients without PTSD and 3,450 patients with PTSD. Of the patients without PTSD, 84.4 percent were men, 64.7 were white and 43.4 percent were married. The average age of the patients was 47.7 years.

Of the cohort of patients with PTSD, 86.5 percent were men, 64.9 percent were white and 44.2 percent were married. The average age of the patients was 42.8 years.

The age adjusted association between PTSD and incident T2DM was significant. After adjusting for obesity, the association was reduced and no longer statistically significant. Results of the full model, which included additional covariate adjustment revealed no association between PTSD and incident type 2 diabetes.

The incidence of type 2 diabetes was similar in patients with PTSD and obesity compared to patients without PTSD but obese. Likewise, Scherrer said, the incidence of diabetes in non-obese patients with and without PTSD was similar (5.8/1000 person years (PY) and 6.4/1000PY, respectively).

"The risk of diabetes in patients with PTSD who are not obese is like that of the general U.S. population without obesity," Scherrer said.

Diabetes prevention should target weight management for both patients with and without PTSD. However, Scherrer says, evidence that patients with PTSD have greater difficulty losing weight may require new interventions to help manage weight and mitigate risk of developing diabetes.

The study calls for additional research to determine if PTSD remission can lead to weight loss and reduced incidence of type 2 diabetes.