Hormonal regultation of growth and obesity

초록

Childhood obesity is a growing problem all over the world, associated with several short-term and long-term metabolic and cardiovascular complications. Growth during childhood occurs at different rates and is influenced by the interaction between genetic and environmental factors. Rapid early weight gain leads to taller childhood stature and higher insulin-like growth factor-I (IGF-I) level. Although childhood obesity is associated with accelerated linear growth, spontaneous and stimulated GH levels are decreased in obese children. Factors which have been implicated in the accelerated growth in obese children include increased leptin and insulin levels, adrenal androgens, IGF-1, IGF-binding protein-1 and GH-binding proteins. Rapid early weight gain is also related to insulin resistance and exaggerated adrenarche. Excess body weight during childhood can influence pubertal development, through an effect on timing of pubertal onset and levels of pubertal hormones. There is clear evidence indicating that obese girls are at increased risk of early pubertal onset and hyperandrogenism. Peripubertal obesity in girls might reduce sex hormone binding globulin levels, which increase the bioavailability of sex steroids including estradiol. In boys, the evidence of obesity-related pubertal progression is less clear with conflicting results. It remains to be dertermined how these systems interrelated and determine growth and pubertal development. Also nutritional exposure remains an area in need of further investigation.