Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis
Corona G, Rastrelli G, Monami M, Saad F, Luconi M, Lucchese M, Facchiano E, Sforza A, Forti G, Mannucci E, Maggi M. Eur J Endocrinol. 2013 Mar 12. [Epub ahead of print


G Corona, Andrology Unit, Dept. of Clin. Physiopathology, University of Florence, Florence, I-50139, Italy.


Objective. Few randomized clinical studies have evaluated the impact of diet and physical activity on testosterone (T) levels in obese men with conflicting results. Conversely, studies on bariatric surgery in men generally showed an increase in T levels. The aim of the present study is to perform a systematic review and meta-analysis of available trials on the effect of body weight loss on sex hormones levels.Design. Meta-analysisMethods. An extensive Medline search was performed including the following words "testosterone", "diet", "weight loss" and "bariatric surgery" and "males". The search was restricted to data from January 1, 1969 up to August 31, 2012.Results. Out of 266 retrieved articles, 24 were included in the study. Of the latter, 22 evaluated the effect of diet or of bariatric surgery, whereas 2 compared diet and bariatric surgery. Overall both low calorie diet and bariatric surgery are associated with a significant (p<0.0001) increase plasma sex hormone binding globulin bound and unbound T levels (TT), bariatric surgery being more effective in comparison with low calorie diet (TT increase = 8.73[6.51-10.95] vs 2.87[1.68-4.07] for bariatric surgery and low calorie diet, respectively; both p<0.0001 vs baseline). Androgen rise is greater in those patients that lose more weight as well as in younger, non-diabetic subjects with a greater degree of obesity. Body weight loss is also associated with and decrease in estradiol and increase in gonadotropins levels. Multiple regression analysis shows that the degree of body weight loss is the best determinant of TT rise (B=2.50±0.98; p=0.029).Conclusions. Present data show that weight loss is associated with an increase of both bound and unbound T levels. The normalization of sex hormones induced by body weight loss is a possible mechanism contributing to the beneficial effects of surgery in morbid obesity.