Post-traumatic stress disorder and type 2 diabetes are both debilitating conditions, but the connection between the two could be stronger than that. New research suggests that women with symptoms of post-traumatic stress disorder could be at an increased risk of developing the metabolic disorder.

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Around 1 in 10 women in the US experience PTSD at some point in their lifetime.

The study, published in JAMA Psychiatry, specifically reports that women experiencing the most symptoms of post-traumatic stress disorder (PTSD) may have almost two times the risk of developing type 2 diabetes in comparison with women who have not been exposed to trauma.

According to the authors of the study, PTSD is a relatively common condition among women in the US, with a lifetime prevalence of 10.4%. The condition is triggered by either experiencing or witnessing a traumatic event.

Symptoms of PTSD include flashbacks to the event, nightmares and severe anxiety. PTSD is also associated with several risk factors for type 2 diabetes, including inflammation, neuroendocrine dysfunction and poor diet.

However, previous studies suggesting an association between type 2 diabetes and PTSD have been unable to clearly define its cause. No firm conclusions have been made as to whether the association is due to PTSD increasing the risk of type 2 diabetes, vice versa, or whether other factors such as child abuse or depression are involved.

As a result, Angela L. Roberts from the Harvard School of Public Health, Boston, MA, and colleagues set out to fully examine the association between the two conditions. They also assessed the potential roles of body mass index (BMI), smoking, diet, alcohol intake and physical activity as risk factors for type 2 diabetes in women with PTSD.

The study is one of the first longitudinal studies of PTSD and type 2 diabetes among civilian women. The authors analyzed data for 49,739 participants from the Nurses’ Health Study II, examining the association between the symptoms of PTSD and type 2 diabetes incidence over the course of 22 years.

Of the 49,739 participants, a total of 3,091 women developed type 2 diabetes during the follow-up period. The researchers observed that women experiencing symptoms of PTSD were more likely to develop type 2 diabetes than participants who had not experienced a traumatic event.

According to the results, the following rates of type 2 diabetes incidence occurred among different groups of participants:

  • Women with six to seven PTSD symptoms: 4.6 cases per 1,000 person-years
  • Women with four to five PTSD symptoms: 3.9 cases per 1,000 person-years
  • Women with one to three PTSD symptoms: 3.7 cases per 1,000 person-years
  • Women exposed to traumatic events but without PTSD symptoms: 2.8 cases per 1,000 person-years
  • Women unexposed to traumatic events: 2.1 cases per 1,000 person-years.

The researchers found that almost half of the increased risk of type 2 diabetes for women with PTSD was due to higher BMI and antidepressant use associated with PTSD. Conversely, smoking, diet, alcohol intake and physical activity did not further account for the increased risk.

“We found that over 22 years of follow-up, PTSD symptoms were associated in a dose-response fashion with the onset of [type 2 diabetes],” write the authors. “Women with the highest number of PTSD symptoms had a nearly 2-fold increased risk of [type 2 diabetes] compared with women without exposure to trauma.”

The authors state their study provides the strongest evidence to date that there could be a causal relationship between PTSD symptoms and the incidence of type 2 diabetes.

Future research using a clinician-administered structured interview is recommended by the authors, however, as they state their findings could underestimate the relationship between PTSD and risk of type 2 diabetes onset. Some participants exhibiting symptoms of PTSD in the study may not have had the condition.

Despite this limitation, the authors believe their findings have implications for both research and practice:

Further research must identify the biochemical and possible additional behavioral changes, such as sleep disturbance, that mediate the relationship between PTSD and onset of [type 2 diabetes]. A better understanding of pathways will facilitate interventions to prevent this disabling disease.”

Previously, Medical News Today reported on a study published in JAMA Psychiatry in which PTSD in women is linked to food addiction.