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

BACKGROUND: 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. OBJECTIVE: 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). METHODS: Baseline serum samples for leptin were obtained every 3 h 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. RESULT: 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. CONCLUSION: We found no evidence that circadian variation in serum leptin concentrations during childhood is associated with long-term changes in children's adiposity.