Post-traumatic stress disorder symptoms in women doubles risk of type 2 diabetes, study suggests

Post-traumatic stress disorder (PTSD) and type 2 diabetes may have a significant connectio, according to new research.
The study, published in JAMA Psychiatry, indicates that women with symptoms of post-traumatic stress disorder may have twice the risk of developing type 2 diabetes compared to women who have not experienced trauma.
Symptoms of PTSD include flashbacks, severe anxiety, and nightmares. It is also associated with inflammation, neuroendocrine dysfunction (a term used to refer to a number of conditions caused by imbalances in the body’s hormone production), and poor dietary choices, all of which are also risk factors for type 2 diabetes.
Although previous studies have suggested the same association between type 2 diabetes and PTSD, none of them has been able to work out why. Whether PTSD increases the risk of type 2 diabetes or vice versa, whether the association is caused by child abuse, or depression: all are possible explanations for the connection.
The study
This study, conducted at the Harvard School of Public Health, Bosto, was established with the aim of explaining the connection between the two conditions. In addition, researchers assessed the role of body mass index (BMI), smoking, diet, alcohol consumptio, and exercise as potential risk factors for type 2 diabetes in women with post-traumatic stress disorder.
The authors analysed the data of 49,739 participants, which spanned the course of 22 years. Of that 49,739, 3,091 women developed type 2 diabetes during the follow-up period. Researchers discovered that those women with PTSD had an increased likelihood of developing type 2 diabetes when compared to the women who had not experienced a traumatic event.
The results
Researchers observed the following rates of type 2 diabetes occurrence among different groups of participants:
Between six and seven PTSD symptoms: 4.6 cases per 1,000 person-years
Four to five symptoms: 3.9 cases per 1,000 person-years
Between one to three PTSD symptoms: 3.7 per 1,000 person-years
Experienced traumatic events but not showing signs of PTSD: 2.8 cases per 1,000 person-years
Unexposed to traumatic events: 2.1 cases per 1,000 person-years
The researchers discovered that around half of the increased type 2 diabetes risk from PTSD was caused by higher BMI and antidepressant use associated with PTSD. However, smoking, diet, alcohol consumptio, and exercise had no discernable impact on the increased risk.
Future research
The authors argue that, while their study provides the strongest evidence yet that there exists a causal relationship between PTSD symptoms and type 2 diabetes, further research is needed. Their findings might underestimate the relationship between the two conditions.
Another limitation of the study is that the participants demonstrating symptoms of PTSD may not have all had the condition.
The authors wrote: “We found that over 22 years of follow-up, PTSD symptoms were associated with a dose-response fashion with the onset of [type 2 diabetes]. 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.
“Further research must identify the biochemical and possible additional behavioural 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.”