Abstract:

Abstract Background Trends in growth and development of children and adolescents are considered to be a "biological standard of living conditions", reflecting a combination of genetic trajectories, environmental factors centered on nutrition and disease, and socio-economic circumstances. Differences in growth and developmental velocity exist between individuals. Objective To construct an equation for predicting maturity offsets from longitudinal data on height, sitting height, and weight to assess the physiological maturity level of individuals. Design Cohort study. Methods According to the Shanghai Longitudinal Growth and Development Study (SLGDS), data were collected from healthy children aged 6.0-14.0 years who had more than four measurements of height, sitting height, and weight with an interval of at least 11 months between each data acquisition. Boys had at least one measurement before 10 years of age and after 12 years of age, and girls had at least one measurement before 9 years of age and after 11 years of age. Fourteen variables of age, height, weight, sitting height and their interactions and ratios were selected for the construction of prediction equations. Correlation analysis and Lasso method were applied to select predictors by gender, and stepwise regression was used to construct the equations. The predictive performance of the equations were evaluated by R2, standard error of estimate (SEE), and Bland-Altman analysis. Main outcome measures Maturity offset［chronological age at the time of measurement-age at Peak Height Velocity (aPHV)］. Results In the SLGDS, 580 children met the inclusion and exclusion criteria. The modeling sample was 439 (180 boys and 259 girls) and the validation sample was 141 (56 boys and 85 girls). Differences in overall measurements between two samples of boys and girls were not significant. The difference was statistically significant in the shorter follow-up duration for boys' modeling sample and the longer duration for girls' modeling sample. Three of the 14 variables were included in the equations for both of boys (age, sitting height, and BMI) and girls (age, sitting height, and quetelet index).Conclusion The maturity offset equations in Shanghai children based on age, sitting height, and BMI for boys, and age, sitting height, and quetelet index for girls were better than the current internationally used maturity offset equations.

Key words: Cohort study, Children and adolescents, Maturity offset, Prediction equation