Learning Objective 1: 1. The learner will be able to know that BMI and increase in BMI before menarche cause early menarche.
Learning Objective 2: 2. The learner will be able to understand that age of menarche is inversely related to body mass index.
Methods: A cross-sectional retrospective study was conducted. A structured questionnaire was used to obtain information on their age at menarche and other relevant data. Their weights and heights were measured for the calculation of current BMI. Categories by the Taiwan Department of Health （DOH）of body mass index (BMI) were < 18.5 (under weight), 18.5 - 24 (normal), 24 - 27 (overweight), and > 27(obese).
Results: Night hundred and sixty one adolescent girls were included in this study. Mean age for all the girls was 18.20 (from16- 21 years old). Mean age at menarche was 12.38 years (from7-18 years old). Mean weight and height were 52.43 kg and 159.31 cm, respectively. There were a significant positive relationship between age at menarche and body height (r= .72, p< .026), negative relationship between age at menarche and body weight (r= -122, p< .001), and age at menarche and BMI (r= -.165, p< .001). After divided the study group by BMI according to those categories used by the Taiwan DOH. There was a significant difference in age at menarche among these four BMI groups (F = 8.18, p < 0.001). The age at menarche in the overweight group was lower than under weight (p< .001) and normal groups (p= .02).
Conclusion: These results suggest that BMI and increase in BMI before menarche cause early menarche. It is necessary to pay attention of height and weight of adolescents and management of diet and exercise behaviors that help maintain healthy weight may prevent and control disorders such as obesity before the menarche period.