Gonadal Dysfunction in Adolescent Boys Enrolled in a Bariatric Surgery Program

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 554-583-Male Reproductive Endocrinology & Case Reports
Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-566
Vivian L Chin*1, Marisa Censani1, Shulamit E Lerner1, Rushika Conroy2, Sharon E Oberfield1, Donald J McMahon1 and Ilene Fennoy1
1Columbia University Medical Center, New York, NY, 2Baystate Medical Center, Springfield, MA
Background: Adolescents with morbid obesity have multiple comorbidities.  Lower testosterone levels have been reported among obese adolescent males but limited data on gonadal function exists.

Objective: To describe gonadal dysfunction and associated metabolic abnormalities among boys in a morbidly obese adolescent population presenting for bariatric surgery.

Methods: 87 boys, mean age 16.2 yrs (13-18, SD 1.2), Tanner stage 4-5, mean BMI 49.5 kg/m2 (35-78, SD 9) were enrolled in the Center for Adolescent Bariatric Surgery Program at Columbia University Medical Center.  Under an IRB-approved protocol, height, weight, waist circumference, Tanner stage, reproductive hormone measures, carbohydrate and lipid markers were obtained in all patients at baseline.  Group comparisons by t-tests and logistic regression models were performed using SAS software.

 Results: 59 boys Tanner 4-5 had hypogonadism with low total testosterone levels for Tanner stage (testosterone ≤200 ng/dL for Tanner 4, ≤350 ng/dL for Tanner 5), while 22 had normal total testosterone and 6 were excluded due to missing data.  In the low testosterone group, 2 boys had both low FSH (FSH<2 mIU/dL) and LH (LH <0.4 mIU/mL) while 10/59 had low FSH only and none had low LH only.  Among those with normal testosterone levels, 4/22 had low FSH only.  There were 4 boys with slightly elevated FSH (FSH >9.2 mIU/mL for Tanner 4 or >11 for Tanner 5) and LH (LH >7) in the hypogonadism group.  Overall, the two groups had similar gonadotropin levels. 

With significance set at α=0.05, the hypogonadal group had greater weight (151.9 vs 134.5 kg, p=.02), higher systolic BP (76 vs 58 percentile, p=.006), greater waist circumference (144 vs 133 cm, p=.01), and higher HOMA-IR (5.1 vs 2.3, p=.0003).

In a separate regression analysis, the model most predictive for low testosterone included weight, BMI z-score, systolic BP, insulin, and AST (χ2 = 17.5) with the second most predictive model consisting of weight, BMI z-score, systolic BP, HOMA-IR and AST (χ2 = 17.4).

Conclusion: 68% of the boys in the morbidly obese adolescent population had low testosterone levels; the mechanism of which remains unclear.  Consistent with obese adults, hypogonadism in morbidly obese adolescents is associated with insulin resistance and obesity, in addition to higher blood pressure and AST levels. However, hypogonadism does not appear to be associated with altered gonadotropin levels. Further investigation is warranted to clarify the relationship between obesity, gonadal dysfunction and insulin resistance in the morbidly obese adolescent male.

Nothing to Disclose: VLC, MC, SEL, RC, SEO, DJM, IF

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm