Clinical data and basal gonadotropins in the diagnosis of central precocious puberty in girls.

OBJECTIVE: The objective of this study was to analyze whether some auxological characteristics or a single basal gonadotropin measurement will be sufficient to distinguish the prepubertal from pubertal status. METHODS: Auxologycal characteristics were recorded and serum LH and FSH were measured by immunochemiluminescence assays before and after GnRH stimulation test in a sample of 241 Caucasian girls with breast budding between 6- and 8-years old. Peak LH levels higher than 5 IU/L were considered a pubertal response. Area under the curve, cut-off points, sensitivity, and specificity for auxologycal variables and basal gonadotropins levels were determined by receiver operating curves. RESULTS: There were no significant differences in age at onset, weight, height, BMI and height velocity between both groups. Bone age was significantly higher in pubertal girls (P < 0.05), although with limited discriminatory capacity. The sensitivity and specificity for the basal LH levels were 89 and 82%, respectively, for a cut off point of 0.1 IU/L. All girls in the pubertal group had a basal LH higher than 1.0 IU/L (positive predictive value of 100%). There was a wide overlap of basal FSH and LH/FSH ratio between prepubertal and pubertal girls. CONCLUSIONS: Auxologycal characteristics should not be used only in the differential diagnosis between prepubertal from pubertal status in 6- to 8-year-old girls. We found a high specificity of a single basal LH sample and it would be useful for establishing the diagnosis of puberty in this age group, reducing the need for GnRH stimulation testing.

Assessment of body composition changes during a combined intervention for the treatment of childhood obesity.

OBJECTIVE: One of the main objectives in the treatment of childhood obesity is to reduce the percentage of body fat mass without negatively affecting fat-free mass (FFM) and, consequently, longitudinal growth. The aim of this study was to analyze the changes that take place in body compartments in a group of patients with obesity under combined treatment. METHODS: This was a longitudinal study with 109 children with obesity 9.1 to 13.9 y of age included in a combined dietary-behavioral-physical activity intervention. Weight, height, skinfold thickness, and waist circumference were registered, and body mass index (BMI), fat mass index (FMI), FFM and waist-to-height ratio (WHR) were calculated over a period of 12 mo. The BMI z-score allowed us to establish two groups: obesity (n = 50) and severe obesity (n = 59). A nutritional improvement was considered when a decrease of BMI z-score of the initial value occurred after 12 mo of follow-up. RESULTS: The improvement in nutritional status reached 61.5% (n = 67). In the obesity group with nutritional improvement (n = 32), FMI significantly decreased (P < 0.005) and there were no significant differences in weight, height z-score, FFM, and WHR throughout the combined intervention. In the severe obesity group with nutritional improvement (n = 35), there were no significant differences in weight, height z-score, FMI, FFM, and WHR throughout combined intervention. CONCLUSIONS: Maintaining a constant weight in the mid- to long term to improve nutritional status would be adequate in children with infantile-juvenile obesity. However, maintaining a steady weight would not be sufficient for those patients diagnosed with severe obesity.