Serum leptin levels in type-I diabetic children and adolescents versus healthy controls: relationship to age, gender, body mass index, gonadal hormones and pubertal stages

ABSTRACT

Since childhood and puberty are periods of major metabolic and endocrine changes, the present study was conducted to [I] Evaluate developmental changes of serum leptin levels in children and adolescents with type-1 diabetes mellitus in comparison with matched healthy controls in respect with chronological age and pubertal stages [2] Evaluate if leptin concentration would be related to obesity observed in children and adolescents with type-1 diabetes during puberty. The study included 60 children diagnosed as type-1 diabetes mellitus by the criteria of American Diabetes Association [ADA] as well as 48 healthy children with matchable age and sex with diabetic patients. The patient and control children were grouped according to their chronological age into 4 groups [6-7yr, 8-10yr, 11-13 yr and 14-16yr] and according to stages of puberty into 3 groups pre puberty P[1] early puberty P[2] and overt puberty P[3]. Serum leptin levels and BMI were measured to all patients and controls. Also, serum testosterone in boys and serum estradiol in girls were measured by ELISA method. Serum leptin levels significantly increased parallel with age and with pubertal stages both in control and diabetic girls. The maximum levels were observed at 14-16yr age group and at overt stage of puberty. Serum leptin levels were significantly higher in diabetic girls than controls at all studied groups. In control boys, leptin levels were significantly higher at 8-10yr and during P[1] stage then a significant decline occurred thereafter. In contrast, the diabetic boys showed no such decline either with age or with pubertal staging. Diabetic boys had significantly higher leptin levels than control boys at all studied groups. Serum leptin levels in girls were significantly higher than boys either in control or diabetic children. Diabetic children [girls and boys] were significantly older than controls during P[2] and P[3] stage. BMI was significantly increased In diabetic children [girls and boys] than controls during P[1], P[2] and P[3] stage whereas serum estradiol in diabetic girls and testosterone in diabetic boys were significantly lower than controls during P[2] and P[3] stages. Significant positive correlations were observed between serum leptin levels versus age, BMI and estradiol hormone in control girls. Also significant positive correlations were found in diabetic girls between serum leptin levels and each of age, BMI and estradiol hormone. In control boys significant negative correlations were observed between serum leptin level and each of age and testosterone hormone whereas non significant with BMI. Significant positive correlations were found in diabetic boys between serum leptin levels and each of age and BMI, while the correlation with testosterone was non significant. In conclusion leptin appears to participate in various endocrinological and physiological process in human body. Among the more notable are obesity and pubertal delay-associated diabetes. Thus, it may be involved in regulation of body weight and signaling the onset of puberty and maintenance of reproductive function thereafter