Weight loss through gastric bypass surgery can reverse hormonal changes

Hormonal changes and diminished sexual quality of life among obese men are related to the degree of obesity, and both are improved after gastric bypass surgery according to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).

“Previous studies have found that obesity is correlated to lower sperm count and can be associated with infertility, but we wanted to know if obesity was biologically associated with an unsatisfying sex life, and if so, could it be reversible,” said Dr. Ahmad Hammoud, MD, of the University of Utah and lead author of the study. “Our results show that the answer to both questions may be yes.”

For this study, researchers followed 64 men over two years who participated in the Utah Obesity Study, which investigated the two-year morbidity of severely obese men undergoing Roux-en-Y gastric bypass surgery compared to controls. Researchers measured weight, BMI (body mass index) and reproductive hormone levels of participants at the beginning of the study and once more two years later. Similarly subjects completed a questionnaire designed to assess the impact of weight on quality of life in obese individuals at the onset of the study and again two years later.

“In our study population, we found that lower testosterone levels and diminished ratings for sexual quality of life were correlated with increased BMI,” said Dr. Hammoud. “Subjects who lost weight through bariatric surgery experienced a reduction in estradiol levels, an increase in testosterone levels and an increase in ratings of sexual quality of life.”

Dr. Hammoud points out that results from this study highlight an association between sexual quality of life and hormonal measures independent from weight. Because this relationship is confounded by biopsychosocial aspects of obesity, further studies are required to determine a cause and effect relationship.

Other researchers working on the study include Mark Gibson, Stephen Hunt, Ted Adams, and Douglass Carrell of the University of Utah; Ronette Kolotkin of Obesity and Quality of Life Consulting in Durham, NC; and A. Wayne Meikle of the ARUP Institute for Clinical and Experimental Pathology at the University of Utah.

The article “Effect of Roux-en-Y Gastric Bypass Surgery on the Sex Steroids and Quality of Life in Obese Men,” will appear in the April 2009 issue of JCEM.

Source: Endocrine Society