Variations in body measurements among girls in relation to their menarche status. Which relevance have age-related-references, when body measurements are age independent during puberty?

Introduction: This study focuses on comparing detailed information on BMI, hip and waist circumference of girls according to their menarche status and, secondly, what is the impact of considering menarcheal age in addition to numerical age on overweight and overwaist. Methods: The description of data are based on two recently conducted cross sectional surveys in Germany: KiGGS (n=1952) and BSCOC (n=1842). All anthropometric data are presented in median, 10th and 90th percentile, stratified by age (11–14yrs) and distributed according to menarche status. Distribution of overweight and overwaist was calculated according to German reference data. Bivariate statistics were obtained in non-parametric tests. Results: The stratification, KiGGS into premenarche (n=913, 47.0%) and postmenarche (n=1029, 53.0%) girls; BSCOC data into premenarche (n=712, 44.4%), recent menarche (n=231, 14.4%) and postmenarche (n=661, 41.2%), of anthropometric measurements shows that the girls who had not yet reached menarche were still growing and „increasing in their weight, hip and waist circumference“, while the girls who recently had experienced menarche showed a higher body height but not a higher body weight, hip and waist circumference. BSCOC analysis demonstrates that puberty changes regarding body composition occur mainly during premenarche and menarche; few changes appear during the time of recent menarche and post-menarche. The frequency distribution of overweight and overwaist in post menarche girls is more than double as high in comparison to premenarche girls of the same age group and decrease within postmenarche and increasing age. Conclusion: The distribution of overweight and overwaist similar in age group but different at menarche status demonstrate the misclassification of girls according to the age related German reference. Maturational status should be taken into account in future anthropometric reference data, not only for clinical but also for epidemiological use.