Women with PTSD gain weight more rapidly than women without disorder
For immediate release: Wednesday, November 20, 2013
Boston, MA — Women with post-traumatic stress disorder (PTSD) gain weight more rapidly and are more likely to be overweight or obese than women without the disorder, find researchers at Harvard School of Public Health (HSPH) and Columbia University’s Mailman School of Public Health. It is the first study to look at the relationship between PTSD and obesity over time.
The study was published online November 20, 2013 in JAMA Psychiatry.
One in nine women will have PTSD at some point over the course of their lifetime—twice as often as men. Women are also more likely to experience extreme traumatic events like rape that carry a high risk for the disorder.
“PTSD is not just a mental health issue,” says study senior author Karestan Koenen, Mailman School associate professor of epidemiology and adjunct associate professor of social and behavioral sciences at HSPH. “Along with cardiovascular disease and diabetes, we can now add obesity to the list of known health risks of PTSD.”
“The good news from the study is that it appears that when PTSD symptoms abate, risk of becoming overweight or obese is also significantly reduced,” says first author Laura Kubzansky, professor of social and behavioral sciences at HSPH. However, despite the growing evidence of potential far-reaching problems associated with PTSD, it’s estimated that only half of women in the United States with the disorder are ever treated. “Hopefully, wider recognition that PTSD can also influence physical health will improve this statistic, leading to better screening and treatments, including those to prevent obesity,” says Kubzansky.
While it’s known that women with PTSD have high rates of obesity, it has been unclear whether PTSD was actually driving the weight gain. To explore the issue, the researchers analyzed data collected from 50,504 women, aged 22-44 years, taking part in the Nurses’ Health Study II between 1989 and 2009. Participants were asked about the worst trauma they experienced and if they had related post-traumatic stress symptoms. The threshold for PTSD was the persistence of four or more symptoms over a month or longer. Common symptoms include re-experiencing the traumatic event, feeling under threat, social avoidance, and numbness.
Normal-weight women who developed PTSD during the study period had 36% increased odds of becoming overweight or obese compared with women who experienced trauma but had no symptoms of PTSD. The higher risk was evident even for women with sub-threshold symptoms levels and remained after adjusting for depression, which has also been proposed as a major risk factor for obesity. In women with PTSD that began prior to the study period, body mass index increased at a more rapid pace than women without PTSD.
The observed effect of PTSD on obesity is likely stronger in the general population of women than in nurses, notes Koenen. “Nurses are great for studies because they report health measures like BMI with a high degree of accuracy. But they are also more health conscious and probably less likely to become obese than most of us, which makes these results more conservative than they would otherwise be.”
Symptoms of PTSD rather than the trauma itself seemed to be behind the weight gain. “We looked at the women who developed PTSD and compared them to women who experienced trauma but did not develop PTSD. On the whole, before their symptoms emerged, the rate of change in BMI was the same as the women who never experienced trauma or did experience trauma but never developed symptoms,” says Kubzansky.
How exactly does PTSD lead to weight gain? The biological pathway is unknown, but scientists have a number of guesses. One is through the over-activation of stress hormones. PTSD may lead to disturbances in functioning of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, each of which are involved in regulating a broad range of body processes, including metabolism. Another is through unhealthy behavior patterns that may be used to cope with stress. Ongoing research is looking at whether PTSD increases women’s preference for processed foods and decreases their likelihood of exercising.
Co-authors include Pula Bordelois, MPH, and Andrea Roberts, PhD, at Harvard School of Public Health; Hee Jin Jun, DrPH, at the Channing Division of Network Medicine at Brigham and Women’s Hospital; Noah Blustone, BA, at Harvard Medical School and Boston University; and Magdalena Cerda, DrPH, at Columbia’s Mailman School.
The study was supported by grants from the National Institute of Mental Health to Dr. Koenen (MH078928 and MH093612). The authors declare no conflict of interest.
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About Harvard School of Public Health
Harvard School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory and the classroom to people’s lives—not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at HSPH teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America’s first professional training program in public health.
About Columbia University’s Mailman School of Public Health
Founded in 1922, Columbia University’s Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, healthpolicy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master’s and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including the International Center for AIDSCare and Treatment Programs (ICAP), and the Center for Infection and Immunity. For more information, please visit www.mailman.columbia.edu