ESPE Abstracts

Background: Elevated serum luteinizing hormone (LH) during gonadotropin-releasing hormone (GnRH) test is documented in girls with central precocious puberty (CPP). Lower LH secretion has been reported in obese girls as compared with lean girls. Few studies have addressed the effect of obesity on peak serum LH levels during GnRH test. This study aimed to determine peak serum LH levels during GnRH analog (GnRHa) test in CPP girls of different body mass index (BMI).

Methods: Medical records of 847 girls with premature breast development of Tanner stages II (TII) and III (TIII) who underwent subcutaneous GnRHa test were reviewed. Girls with premature breast development concomitant with accelerated height velocity and advanced bone age were defined as CPP, whereas girls without above findings were defined as premature thelarche (PT). All of them were classified into 3 groups according to their BMI Z-scores as lean, overweight and obese groups. Clinical data and GnRHa test results were analyzed.

Results: There were 553, 188 and 106 girls in lean, overweight and obese groups, respectively. Four hundred and thirty-nine and 408 girls had TII and TIII breasts, respectively. CPP was diagnosed in 520 girls (216, TII and 304, TIII). Medians (IQRs) peak serum LH levels did not differ among 3 BMI groups (lean, overweight and obese, respectively, CPP, TII: 6.3 (4.7, 9.9), 8.8 (6.0, 16.1) and 6.7 (5.3, 10.1) IU/l, P=0.114; TIII: 8.6 (5.9, 16.7), 10.8 (6.6, 15.4) and 8.2 (5.2, 21.6) IU/l, P=0.300; PT, TII: 2.7 (2.0, 4.1), 2.6 (1.9, 3.3) and 1.8 (1.3, 2.6) IU/l, P=0.065; TIII: 2.7 (2.1, 3.8), 2.4 (1.6, 3.1) and 1.9 (1.6, 2.8) IU/l, P=0.093). Peak serum LH cut-off for CPP diagnosis at the comparable sensitivity and specificity seemed to be lower in the overweight (TII: 4 IU/l, sensitivity 88%, specificity 93%; TIII: 4 IU/l, sensitivity 85%, specificity 86%) and obese groups (TII: 4 IU/l, sensitivity 83%, specificity 90%; TIII: 4 IU/l, sensitivity 86%, specificity 98%) as compared with those of the lean group (TII: 4.5 IU/l, sensitivity 85%, specificity 83%; TIII: 4.5 IU/l, sensitivity 85%, specificity 87%).

Conclusions: Peak serum LH level during GnRHa test were not different among girls with CPP of different BMIs. However, lower peak serum LH cut-off for CPP diagnosis in overweight and obese girls might be considered.