The concordance between ultrasonographic stage of breast and Tanner stage of breast for overweight and obese girls: a school population-based study.

Objectives: In this study, we evaluated the concordance between the ultrasonographic stage of breast (US B) and Tanner stage of breast (TS B) for overweight and obese girls based on a school population study.

Methods: We conducted multistage, stratified cluster, and random-proportional sampling and ultimately included 221 girls (aged 6-10 years).

Results: This study revealed that the concordance was poor (accuracy=0.19 (95% confidence interval: 0.14, 0.25)) between US B and TS B among the 221 participants. When our subjects were stratified by weight, we observed a weak association between US B and TS B in the thin/normal weight group (r=0.34, p=0.001) but not in the overweight (r=0.097, p=0.38) or obese groups (r=-0.19, p=0.206), and as the body mass index (BMI) z-score increased, the overestimation ratio of TS B increased. US B manifested a positive correlation with breast bud diameter (BD) (r=0.885, p<0.001), follicle-stimulating hormone (r=0.235, p=0.009), and luteinizing hormone (r=0.192, p=0.037), but this was not the case with TS B.

Conclusions: As the BMI z-score increased, the correlation between the two methods declined, and the overestimation ratio of TS B increased. US B is an objective and quantitative method used to evaluate breast development, and whether BD might replace US B as a routine diagnostic method to evaluate breast development in clinical practice needs to be confirmed in larger-sample studies.