Chilhood obesity: relationship between leptin, thyrotrophin and obesity

Abstract

Leptin is a protein hormone synthesized primarily by adipocytes. In the hypothalamus, this hormone inhibits food intake and enhances energy expenditure. In obese patients, leptin is increased, indicating resistance to its action. It has been reported that between 10 and 25 % of obese patients present slightly increased levels of thyrotrophin, which is not related to thyroid pathology. Leptin has been suggested as a nexus between obesity and the increase in thyrotrophin. There are no published studies in the prepubertal population.
Objective: to study the relationships between serum leptin, obesity and serum thyrotrophin in prepubertal obese patients.
Materials and methods: 30 prepubertal patients, between 4 and 11 years of age, were included (body mass index z-score ≥ 2). Leptin was measured by an enzyme immunoassay and thyrotrophin by a chemiluminescence immunoassay. Weight, height and waist perimeter were measured and body mass index and body mass index z-score were calculated, using a software. Shapiro-Wilk test and Spearman and Pearson correlation were used.
Results:
leptin correlated positively with body mass index (r= 0.484; p = 0.007), waist perimeter (r= 0.788; p = 0.004) and thyrotrophin (r = 0.476, p = 0.012). There was no correlation between thyrotrophin and body mass index. The correlation between the parameters varied when the population was discriminated by sex.
Conclusions: our results show evidence that in obese prepubertal patients, leptin is positively correlated with body mass index, waist circumference and thyrotrophin.