Department of Growth and Development, Capital Institute of Pediatrics, Beijing, China.
Department of Growth and Development, Capital Institute of Pediatrics, Beijing, China
BMJ Open. 2024 Feb 26;14(2):e077076. doi: 10.1136/bmjopen-2023-077076.
This study aimed to assess the predictive value of body mass index (BMI) and skeletal maturity for the occurrence of early menarche in Chinese girls.
A cross-sectional analysis was conducted on 785 girls aged 8.1-14.6 years who visited our hospital within 3 months of menarche onset. Early menarche was defined as menarche age (MA) <10 years. Skeletal maturity was classified based on the difference between bone age (BA) and chronological age (CA), termed BA-CA; advanced BA was defined as BA-CA>2 years.
The average MA was 10.7 (SD: 1.1) years, with a prevalence of early menarche of 23.3%. BA exhibited relative stability compared with MA, with an average of 12.8 (SD: 0.5) years at menarche onset. At menarche onset, the average height, weight and BMI were 149.1 (SD: 5.1) cm, 43.3 (SD: 7.2) kg and 19.4 (SD: 2.8) kg/m², respectively. Logistic regression analyses indicated that every 1-year increment in BA-CA was independently associated with a 18.90-fold higher risk of early menarche (95% CI 11.77 to 30.32), respectively, and remained statistically significant even after adjusting for height or mid-parental height. Furthermore, the prediction of BA-CA for early menarche demonstrated a dose-dependent pattern across BMI categories, with the greatest risk observed in normal-weight girls, the lowest risk in obese girls and an intermediate risk in overweight girls at the same degree of BA advancement.
Our findings provide evidence supporting the significant contributions of BMI and skeletal maturity in predicting early menarche among Chinese girls at menarche onset. Additionally, the results suggest a dose-dependent relationship between skeletal maturity and BMI categories, with normal-weight girls displaying a higher risk of early menarche compared to overweight and obese girls with the same degree of BA advancement.
本研究旨在评估体重指数（BMI）和骨骼成熟度对中国女孩初潮发生的预测价值。
对 785 名年龄在 8.1-14.6 岁、初潮后 3 个月内就诊于我院的女孩进行横断面分析。初潮年龄（MA）<10 岁定义为早初潮。骨骼成熟度根据骨龄（BA）与实际年龄（CA）的差异来分类，称为 BA-CA；BA-CA>2 岁定义为 BA 提前。
平均 MA 为 10.7（SD：1.1）岁，早初潮率为 23.3%。BA 与 MA 相比相对稳定，初潮时平均为 12.8（SD：0.5）岁。初潮时，平均身高、体重和 BMI 分别为 149.1（SD：5.1）cm、43.3（SD：7.2）kg 和 19.4（SD：2.8）kg/m²。Logistic 回归分析表明，BA-CA 每增加 1 年，早初潮的风险就会增加 18.90 倍（95%CI 11.77-30.32），即使在调整了身高或中亲身高后，这种关联仍然具有统计学意义。此外，BA-CA 对初潮的预测在 BMI 类别中呈现出剂量依赖性模式，在同样程度的 BA 提前情况下，正常体重女孩的风险最大，肥胖女孩的风险最小，超重女孩的风险处于中间。
我们的研究结果为 BMI 和骨骼成熟度在预测中国女孩初潮时的重要作用提供了证据。此外，结果提示骨骼成熟度和 BMI 类别之间存在剂量依赖性关系，与超重和肥胖女孩相比，同样程度的 BA 提前，正常体重女孩初潮的风险更高。
