Relationship between Body Mass Index and Early Menarche of Adolescent girls in Thimphu

Abstract

Background: Studies have shown trends of decreasing age at menarche and its consequences of obesity and breast cancer. The objective of the study is to determine the prevalence of early menarche and determine association between Body Mass Index and early menarche in adolescent girls.

Method: The explanatory cross-sectional study was conducted with 286 pairs of mother- daughter in four schools in Thimphu. Data regarding menstrual age, mother’s age at menarche

and socioeconomic status was collected using self-administered questionnaire from the girls and their parents. The measurement of height and weights of the girls were taken during the fieldwork.

Result: The average age of the participants were 11.46+1.23 and trend for the reduction of mean age at menarche has been noted between mother and daughter. The study shows the relation between BMI and early menarche in adolescent girls. Most of the students 62.5% (42.5% + 20%) experienced menarche at 11-12 years, and among all the participants 70 % (5% + 22.5% + 42.5) experienced menarche at early age of between 9 and 11 years. Only 26.3% (20% + 6.3%) experienced menarche at normal age between 12 and 13 years. Similarly, only a small number of students 2.6% (1.3% + 1.3%) experienced a delayed menarche between 14 and 15 year with statistical significance only with under weight.

Conclusion: The findings add to the evidence that there is prevalence of early menarche and establish the relationship between BMI and early menarche. However, there are cross-national variations with risk factors. The change in the trend of early menarche could also be the genetic variation, lifestyle and other factors not only the BMI in determining early menarche. Further similar studies on girls from other parts of Bhutan are needed for scientific data.