Overweight and Obesity and Puberty Development Cohort Study

Precocious puberty and childhood overweight and obesity are important public health problems that both had adverse effects, which including psychological symptom in childhood, short final height or reproductive dysfunction in adulthood, on children's physical and psychological development.The prevalence of precocious puberty and childhood overweight and obesity are both high, and a growing body of epidemiological studies suggested that there was a close relationship of childhood overweight and obesity with puberty development, especially in girls. However, the underlying mechanism between them is unclear. Existing evidence shows that the occurrence of precocious puberty and overweight and obesity are the result of interaction of multiple factors, which consists growth environment and genetics, and many previous studies provided that more overlapping genes existed between obesity and precocious puberty patients, suggesting that common genes may result in these diseases. Therefore, based on a case control study, which will investigate the associations between obesity pleiotropic genes and early puberty, the researchers will collect information related to obesity, growth environment factors and risk genes in this study to evaluate the relationships of these related factors and precocious puberty, and to further explore whether there exists biological interaction effects of these risk factors on sexual precocity. This project has been approved by the Ethics Committee of Shanghai Children's Medical Center.

1. Purpose: A prospective cohort study. The aim of this study is to investigate the effect of pediatric weight status and childhood growth environment on puberty development.
2. Participants: Participants are primary school children aged 6- to 12-year-old, and their parents must be willing to engage in this study and comply with study requirements.
3. Study Procedure: According to geographic and population distribution, about 40 schools included in this study by stratified, random clustering sampling in three cities of China, including Qufu, Zhongshan and Huhhot. Participant will accept anthropometric measuring by clinicians from the three collaborated hospitals, including BoAi Hospital of Zhongshan, QuFu People' s Hospital and Inner Mongolia People's Hospital. This study will be conducted among children of grade 1 to 3 from selected schools in 2019 and the first, secondary and third follow-up will be conducted one, two and three year later respectively.
4. Exposures: Participants with overweight or obesity will be included in overweight and obesity group at baseline.
5. Related risk factors: Childhood growth and family environmental information, including physical activity, diet habit, sleep duration, family structure and family social-economic status, will be collected by parent-reported questionnaire;
6. Outcomes measures: Participants' puberty stage will be evaluated by secondary sexual characteristics development by physician palpation.

Eligibility Criteria:
Inclusion Criteria:

* Children over 6 years old from grade 1, 2 and 3 in selected primary schools in Zhongshan, Qufu and Huhhot since 2019

Exclusion Criteria:

* Children with overweight or obesity had a history of hormone drug treatment last for 6 months