1383-P: Relationship between Body Fat Mass and Insulin Resistance in Nonobese Patients with Idiopathic Hypogonadotropic Hypogonadism and Normal Glucose Tolerance

Objective: The purpose of this study was to investigate the relations between body fat mass and insulin resistance in non-obese patients with idiopathic hypogonadotropic hypogonadism (IHH) and normal glucose tolerance.

Methods: A total of 42 patients with IHH and BMI lower than 28 kg/m² from January 2013 to October 2017 were recruited. Patients were required to have a normal glucose tolerance test for inclusion in the study. Ten Healthy subjects having a routine physical examination and a normal glucose tolerance test were also recruited as control group. Laboratory studies included fasting insulin, testosterone, and lipids. Waist circumference (WC) , weight, and body fat mass were measured, and waist-to-hip ratio (WHR) , body mass index (BMI) , HOMA-IR, and LogHOMA-B were calculated. Data were compared between groups, and linear regression was used to determine relations.

Results: Blood pressure, fasting glucose, BMI, WHR, and lipids were similar between the groups. Fasting insulin levels (15.61 ± 7.66 mIU/L vs. 7.60 ± 3.84 mIU/L) , logHOMA-B (2.39 ± 0.29 vs. 2.03 ± 0.21) , HOMA-IR (3.38 ± 1.71 vs. 1.64 ± 0.91) , and body fat mass (30.49 ± 9.46% vs. 21.± 4.31%) were significantly greater in the IHH group compared with those in control group (all, P < 0.05) . Multivariable linear regression showed that in IHH patients body fat mass was an independent predictor of fasting insulin level (β = 0.71, 95% confidence interval [CI]: 0.54, 0.88, P < 0.01) , LogHOMA-B (β = 0.02, 95% CI: 0.001, 0.032, P < 0.05) , and HOMA-IR (β = 0.14, 95% CI: 0.09, 0.18, P < 0.05) .

Conclusion: Body fat mass is an independent predictor of insulin resistance in IHH patients with normal glucose tolerance.