AUTHOR=Ebenibo Sotonte , Edeoga Chimaroke , Owei Ibiye , Dagogo-Jack Sam 

TITLE=Basal and Dynamic Leptin Secretion: Association with Cardiometabolic Risk and Body Weight Trajectories in African-Americans and European-Americans

JOURNAL=Frontiers in Endocrinology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2018.00012

DOI=10.3389/fendo.2018.00012

ISSN=1664-2392

ABSTRACT=<sec id="ST1"><title>Background</title><p>Fasting plasma leptin levels reflect fat mass, but dynamic leptin responses to secretagogues, and the influence of race/ethnicity, have not been well studied. Here, we compared basal and stimulated leptin levels in relation to cardiometabolic risk and weight trajectories in black and white subjects.</p></sec><sec id="ST2"><title>Subjects and methods</title><p>We studied 254 (127 black and 127 white) normoglycemic adults enrolled in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study. At baseline and annually, POP-ABC participants underwent physical examination, oral glucose tolerance test, and measurements of body fat (dual energy X-ray absorptiometry), fasting plasma leptin, insulin, cortisol, lipids, and leptin secretory response to single-dose (2 mg) dexamethasone (dex). The interactions among basal and stimulated leptin and changes in adiposity/cardiometabolic measures during the ensuing year were then analyzed.</p></sec><sec id="ST3"><title>Results</title><p>The mean (±SD) fasting leptin level (50.6 ± 47.7 vs. 39.5 ± 37.6 ng/mL, <italic>P</italic> = 0.004) and body mass index (BMI) (31.9 ± 7.14 vs. 29.0 ± 7.66 kg/m<sup>2</sup>, <italic>P</italic> = 0.0043) were higher in black women vs. white women, but similar in black men vs. white men (leptin: 12.4 ± 2.07 vs. 11.1 ± 1.40 ng/mL; BMI: 29.4 ± 7.68 vs. 28.1 ± 4.23 kg/m<sup>2</sup>). The peak leptin response to dex (~200% baseline) did not differ significantly by gender or race. Total body fat correlated positively with fasting leptin (<italic>r</italic> = 0.81, <italic>P</italic> &lt; 0.0001) and inversely stimulated leptin levels (<italic>r</italic> = −0.26, <italic>P</italic> &lt; 0.0001). Fasting leptin was unrelated to 1-year change in weight or fat mass, whereas stimulated leptin levels were significantly associated with 1-year trajectories in weight (<italic>P</italic> = 0.0016) and total fat mass (<italic>P</italic> = 0.0035). Stimulated leptin levels also had significant interactions with insulin sensitivity (homeostasis model of insulin resistance, <italic>P</italic> = 0.01), triglycerides (<italic>P</italic> = 0.0078), fasting glucose (<italic>P</italic> = 0.027), systolic blood pressure (<italic>P</italic> = 0.037), and high-sensitivity C-reactive protein (<italic>P</italic> = 0.027).</p></sec><sec id="ST4"><title>Conclusion</title><p>We found no significant ethnic disparities in basal or dynamic leptin secretion in relation to adiposity. Fasting leptin levels were not associated with 1-year weight change, while stimulated levels showed weak though significant association with 1-year weight change.</p></sec>