FP09-5 Basal Versus Stimulated Leptin Levels for Predicting Trajectories of Future Weight and Fat Mass

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP09-Obesity: Physiologic Responses to Energy Balance Disruption
Bench to Bedside
Saturday, June 15, 2013: 11:00 AM-11:30 AM
Presentation Start Time: 11:20 AM
Room 307 (Moscone Center)

Poster Board SAT-697
Chimaroke Edeoga*, Sotonte Ebenibo and Samuel Dagogo-Jack
University of Tennessee Health Science Center, Memphis, TN
Purpose: Leptin regulates body weight and fasting (basal) plasma leptin levels are closely correlated with body fat mass, but dynamic leptin responses to secretagogues have not been well-studied.  Fasting hypoleptinemia has been suggested as a risk factor for future weight gain in Pima Indians, but data are lacking for other populations, and the relationship between dynamic leptin secretion and future weigh change is unknown.  We tested the hypothesis that stimulated leptin levels better predict future weight change than basal leptin levels.

Subjects and Methods: We studied 254 (127 white, 127 African American {AA}) nondiabetic subjects (mean{SD} age 44.2 + 10.6 y) enrolled in our ongoing Pathobiology of Prediabetes in a Bi-racial Cohort (POP-ABC) study1.  At baseline and annually, POP-ABC participants underwent physical examination, OGTT, and measurements of body fat (DEXA) and fasting leptin levels, among other assessments. Dynamic leptin secretion was assessed at baseline, using the method of Dagogo-Jack et al 2(with a reduced dose, 2 mg, of dexamethasone {dex}). The interactions among basal and post-dex plasma leptin levels and changes in weight, BMI, and total fat mass during the ensuing 1 year were analyzed using ANOVA and linear regression.

Results: There were no gender or ethnic differences in the correlation between fasting leptin and total fat mass (r= ~ 0.81). The peak plasma leptin response to dex (% baseline) showed marked individual variability (-9% to +760%). However, the mean change was similar (~100% above baseline) in men and women and in AA and Caucasians. Fasting leptin levels were inversely correlated with peak dex-induced leptin (r= -0.26, P=0.037). Fasting leptin levels had a marginal relationship with 1-yr changes in weight (P=0.0496) and no significant relationship with total fat mass (P=0.3394). In contrast, the changes in leptin following dex significantly predicted 1-yr trajectories in weight (P=0.0016) and total fat mass (P=0.0023). These findings were similar in men and women and in AA and Caucasians. When the data were analyzed by percentiles of leptin response to dex, subjects in the <25th, 25-50th, and 51-75th percentiles maintained stable (or decreasing body fat), whereas those in the >75-90th and >90thpercentiles of dynamic leptin secretion gained fat mass during the ensuing 1 year.

Conclusion: Our data indicate that basal leptin levels convey uncertain information regarding the risk of future adiposity in African Americans and Caucasians, whereas stimulated leptin levels reliably predict 1-yr trajectories in weight and fat mass. The Dexamethasone-Leptin Test thus might be of prognostic value in predicting future changes in adiposity.

1. Dagogo-Jack S, Edeoga E, Ebenibo S, Chapp-Jumbo E. Pathobiology of Prediabetes in a Bi-racial Cohort (POP-ABC) Study: Baseline characteristics of enrolled subjects. J Clin Endocrinol Metab [Epub ahead of print 2012 Nov 1.] PMID: 23118422 2. Dagogo-Jack S, Selke G, Melson AK, Newcomer JW. Robust leptin secretory responses to dexamethasone in obese subjects. J Clin Endocrinol Metab 82:3230-3233, 1997.

Nothing to Disclose: CE, SE, SD

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

Sources of Research Support: Supported by NIH grant 1R01 DK067269.