Circadian variation of serum leptin and adipose tissue changes in children.

Abstract

Higher morning serum leptin values are associated with larger adipose tissue gains in children; however, it is unclear if leptin circadian variation is itself associated with adipose tissue changes during growth. We studied the association of circadian variation in leptin with change in total body fat mass (TBFM), total body percentage fat (%FM), and trunk fat mass (TrFM). Baseline serum samples for leptin were obtained every 3h for 24 h from 130 children (baseline age 9.6 ± 2.5y; 51.1% male; BMI-Z 1.59) with mean follow-up of 11.1 ± 4.0y and underwent dual-energy x-ray absorptiometry. ANCOVA models examined change in TBFM, %FM, or TrFM as dependent variables and number of years of follow-up, sex, race, baseline age, pubertal status, initial visit body composition, and initial visit serum leptin circadian variables (maximal diurnal leptin [acrophase], diurnal amplitude, and percentage change of amplitude) as independent factors. Although initial visit mesor (24 h average) leptin was positively associated with initial visit TBFM (r2 =0.78, p < 0.001), %FM (r2 =076, p < 0.001), and TrFM (r2 =0.71, p < 0.001), none of the circadian leptin variables studied was significantly associated with change in TBFM, %FM, or TrFM. We found no evidence that circadian variation in serum leptin concentrations during childhood is associated with long-term changes in children's adiposity.