Supplemental materials for: Current pubertal development in Chinese children and the impact of overnutrition, lifestyle and perinatal factors

<strong>Context: </strong>Pubertal onset has been decreasing in many countries but there has been no data on pubertal development in Chinese children over the last decade. <strong>Objective: </strong>The primary objective of the study was to evaluate the current status of sexual maturation in Chinese children and adolescents. Secondary objectives were to examine socio-economic, lifestyle and auxological associations with pubertal onset. <strong>Design: </strong>A national, cross-sectional health survey. <strong>Setting: </strong>The community-based setting. <strong>Participants: </strong>A multistage, stratified cluster random sampling method was used to select a nationally representative sample, consisting of 231,575 children and adolescents(123,232 boys and 108,343 girls) between 2017 and 2019. <strong>Main Outcome Measure: </strong>Growth parameters and pubertal staging were assessed by physical examination. <strong>Results: </strong>Compared to 10 years previously the median age of Tanner 2 breast development and menarche were similar at 9.65 years and 12.39 years respectively. However, male puberty occurred earlier with a median age of testicular volume ≥4 ml of 10.65 years. Pubertal onset did occur earlier at the extremes with 3.3% of the girls with breast development between 6.5-6.99 years old increasing to 5.8% by 7.5-7.99 years old. Early pubertal onset was also noted in boys, with a testicular volume ≥ 4 ml noted in 1.5% between 7.5-7.99 years increasing to 3.5% between 8.5-8.99 years old. Obesity and overweight increased the risk of developing earlier puberty compared to the normal weight in both boys and girls. <strong>Conclusions: </strong>Over the past decade, pubertal development is occurring earlier in Chinese children. While the cause is multifactorial, overweight and obesity are associated with earlier puberty onset. The currently-used normative pubertal data of precocious puberty may not be applicable to diagnose precocious puberty.