The Diagnostic Value Of Basal Gonadotropin And Pelvic Ultrasound For Central Precocious Puberty In Girls With Different BMI

Objective To explore the diagnostic value of basal gonadotropin and pelvic ultrasound in the diagnosis of central precocious puberty(CPP)in girls according to their body mass index(BMI).Method 611 girls presented with breast development at 6~8 years of age,who were diagnosed with CPP or premature thelarche(PT),and visited the Pediatric Endocrinology Clinic at Fuzhou Children's Hospital of Fujian Province from 2014 to 2018 were enrolled in this study.Breast development in these girls were in Tanner stage 2 or Tanner stage 3 without menarche.The girls were grouped according to their BMI: normal weight(n=444),overweight(n=90)and obesity(n=77).Physical measurements,bone age assessment,gonadotropin-releasing hormone(Gn RH)stimulation test,pelvic ultrasound and other examinations were taken for all girls.SPSS18.0 was used for statistical analysis,Student t-test or Mann-Whitney U was used to analyze the differences between CPP and PT groups.Spearman's correlation was used to analyze the correlation between peak gonadotropin and basal gonadotropin levels.Receiver operating characteristic curves(ROCs)were constructed to explore the cut-off and diagnostic values to differentiate girls with CPP from PT.Results 1 In the group of normal weight,there were 243 CPP girls and 201 PT girls.In the overweight group,there were 57 CPP girls and 33 PT girls.In the obesity group,there were 37 CPP girls and 40 PT girls.No statistical difference was observed in diagnostic age between CPP and PT girls(all P>0.05).2 Basal LH,FSH and LH/FSH levels and the uterine and ovary volumes were higher in girls with CPP vs.PT in each weight group(P<0.01).3 There was a positive correlation between basal LH value and peak LH,basal LH/FSH value and peak LH /FSH in CPP girls with normal weight,overweight(P<0.01).There were no statistically correlation between basal LH value and peak LH,basal LH/FSH value and peak LH /FSH in CPP girls with obesity(P>0.05).4 The area under the ROC curve(AUC)of LH basal value for CPP diagnosis of normal weight,overweight and obese girls were 0.842,0.843 and 0.794.When the youden index were at the maximum(0.54,0.61,0.48),the cut off values of the basic LH value were 0.165IU/L,0.225IU/L,and 0.145IU/L.The sensitivity were 73.3%,66.7% and 77.8%,and the specificity were 80.4%,93.9%,and 70.0%,respectively.The diagnostic value of basal FSH,basal LH/FSH,uterine length,uterine volume and ovarian volume were different in normal weight,overweight and obese girls.5 For normal-weight girls,if basal LH value >0.165IU/L,basal LH /FSH >0.075 and uterine volume >1.345 ml were used as the cut-offs,the sensitivity was 42.0% and specificity was 98.0%.For overweight CPP girls,if LH basic value >0.225IU/L and ovarian volume >1.335 ml were used as cut-offs,the sensitivity was 61.4% and specificity was 97.0%.For obese girls,if LH>0.145IU/L and uterine volume>2.05 ml were used as cut-offs,the sensitivity was 21.6% and specificity was 100%.Conclusion 1.The best diagnostic value of basal LH for CPP are different in normal weight,overweight and obese girls,but it is reliable to differentiate CPP and PT for all girls.2.The combined application of basal LH and uterine volume or ovarian volume may improve the diagnostic accuracy of CPP girls,CPP and PT could also be distinguished.