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Bariatric surgery, BMI, testosterone and sexual function

Body mass index (BMI) and waist circumference were negatively correlated with the level of testosterone and BMI was an independent risk factor for the severity of erectile dysfunction (ED), according to the outcomes from a study by researchers from Jinan University, Guangzhou, Guangdong, China. The findings were featured in the paper, ‘Effects of bariatric surgery on testosterone level and sexual function in men with obesity: A retrospective study’, published in Frontiers in Endocrinology.

They noted that LSG and LRYGB led to “positive and sustained improvement in sexual function of men with obesity”, however they stated that more researcher was needed to as this mechanism might be influenced by many factors, “as the degree of weight loss effect and other indexes could not predict the improving degree of scores of sexual function.”

Using data from the Chinese Obesity and Metabolic Surgery Database (COMES Database), which is endorsed by the Chinese Society for Metabolic and Bariatric Surgery (CSMBS), the study included 59 male patients with obesity (mean BMI 40.37±7.57kg/m2 (ranging from 28.09 to 59.99 kg/m2) and mean age of 32.1±6.7 years (ranging from 22 to 51 years).

In the studied patients, 50 (84.7%, 50/59) of them had scores that conformed to the ED definition. Thirty-one patients completed the International Index of Erectile Function (IIEF) questionnaire at least one year after the operation. Twenty-eight patients underwent LSG, while the other 31 patients underwent LRYGB. The mean follow-up was 23.2 months, ranging from 12 to 45 months.


Univariate analysis showed that BMI, level of serum Zn, C-peptide and HOMA-IR were predictive factors of pre-operative ED grade. No significant difference were found for T2DM, hypertension, smoking, drinking, educational level and marital status. The multivariate logistic regression analysis revealed that BMI was the single independent risk factor (p<0.001).

Pearson’s correlation showed that the preoperative testosterone level had significant relations with BMI, weight, neck circumference, breast circumference, waist circumference, hip circumference, vitamin A, vitamin E, albumin, HDL-c and HOMA-IR. Pre-operative testosterone levels had negative correlations with BMI (p=0.004) and waist circumference (p=0.005).

Overall, there were significant improvements in scores of EF (pre-operation 52.22 ± 10.79 vs. post-operation 61.46 ± 7.93, p<0.001) and its domains in the patients, meaning that they were more satisfied with their EF and sex life postoperatively.

Regarding the procedure type, the researchers found that there was no significant difference in baseline and weight loss, levels of testosterone and positive effects on sexual function between the LSG and LRYGB groups.

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