Sex-differential testosterone response to long-term weight loss

Area of Science:

• Endocrinology
• Metabolic Surgery
• Obesity Medicine

Background:

• Obesity is linked to gonadal dysfunction, a common issue for individuals undergoing weight loss interventions.
• Understanding the impact of weight loss on sex hormones and other endocrine axes is crucial for managing comorbidities associated with obesity.

Purpose of the Study:

• To investigate the incremental effects of weight loss on gonadal axes in both men and women over a 3-year period.
• To compare changes in sex hormones between dietary interventions and various bariatric procedures (RYGB, SG, LAGB).
• To assess alterations in the corticotropic, somatotropic, and thyroid axes following weight loss interventions.

Main Methods:

• A prospective, observational study involving 61 adults with a Body Mass Index (BMI) >30 kg/m².
• Endocrine parameters were measured at baseline and at six time points over 36 months.
• Changes in hormones were analyzed in relation to the amount of weight lost and compared across different weight loss interventions.

Main Results:

• Each kilogram of weight lost correlated with a 0.6% increase in total testosterone in men and a 0.8% decrease in women.
• In women, bariatric surgery (RYGB, SG) led to significant reductions in total testosterone and free androgen index (FAI) compared to dietary intervention.
• Weight loss was associated with a decline in adrenocorticotropic hormone and an increase in insulin-like growth factor-1 across the cohort.

Conclusions:

• Hormonal changes, particularly testosterone reduction in women post-bariatric surgery, are proportional to weight loss and independent of age or menopausal status.
• Further research is needed to explore the impact of androgen reduction on functional and cognitive status in postmenopausal women.
• Observed alterations in pituitary hormones may contribute to the metabolic benefits of bariatric surgery.