"We have all seen visible evidence that the United States is currently facing an obesity crisis," said Bethany Klopfenstein, M.D., a fellow in the division of endocrinology of the OHSU School of Medicine. "The obesity epidemic is not only expanding the waistlines of Americans. It is also being connected to the unhealthy surge in type 2 diabetes cases, cardiovascular disease and other associated disorders. For women, a sudden increase in weight often occurs following menopause. This not only raises obesity-related health concerns. The weight gain also can be an emotionally difficult occurrence for aging women."
To conduct this research project, scientists observed a group of 46 pre- and postmenopausal women. In the postmenopausal group, some of the women involved in the study were receiving hormone replacement therapy, others were not. By analyzing data from study participants, researchers determined that the drop in estrogen levels commonly associated with menopause is linked to an increase in a form of the hormone cortisol.
Another key finding was that postmenopausal women who were not receiving hormone replacement therapy had higher cortisol levels than those who were receiving therapy. On average, these untreated women with higher cortisol levels also witnessed an increase in abdominal fat when compared with women receiving the therapy.
"These findings also suggest that estrogen replacement therapy protects women from developing high cortisol levels and increased abdominal fat," said Jonathan Purnell, M.D., an associate professor of medicine (endocrinology, diabetes and clinical nutrition) in the OHSU School of Medicine and a researcher in OHSU's Center for the Study of Weight Regulation and Associated Disorders. "We believe that by preventing this rise in cortisol, we can possibly delay or prevent weight issues and the many weight-associated disorders in some of these women."
To further confirm the relationship between estrogen replacement and cortisol levels, researchers treated seven postmenopausal women not already undergoing hormone replacement therapy with a synthetic form of estrogen. After one month of therapy, these women, who all previously had heightened cortisol levels, witnessed decreased cortisol at levels close to that of premenopausal women.
The findings also suggest that over time, this group of women may also witness a decrease in abdominal fat. However, more long-term studies involving delayed estrogen replacement therapy would be required to confirm this theory.
The research was funded by the National Institute of Diabetes and Digestive Kidney Diseases.
The OHSU Center for the Study of Weight Regulation and Associated Disorders conducts research into causes of and treatments for obesity. Prior to the creation of this center, OHSU has been involved in a number of key weight regulation discoveries, including the identification of specific cells in the brain involved in weight control. OHSU researchers have also identified hormones involved in weight loss and weight gain.
OHSU includes the schools of dentistry, medicine, nursing and science and engineering; OHSU Hospital and Doernbecher Children's Hospital; numerous primary care and specialty clinics; multiple research institutes; and several outreach and community service units.