Objective: To explore the association between different family factors and children’s puberty timing, and to provide a reference for further research on puberty development of children. Methods: A prospective cohort study was conducted on a total of 1 237 children in one district, Chongqing, using targeted sampling. Cox regression was used to analyze the association between family factors and the puberty timing of children. Results: The results of univariate analysis showed that baseline age and BMI were risk factors of early puberty timing in boys and girls (P<0.01). Breast development (HR=1.27, 95%CI=1.04-1.54) was observed earlier in vaginal delivery than in cesarean section. Self-conscious family economic condition is good is the protective factor for the early timing of girl’s menstruation (HR=0.81, 95%CI=0.66-0.99), pubic hair development(HR=0.80, 95%CI=0.65-0.97) and the boy’s puberty development (Testicular development HR=0.69, 95%CI=0.58-0.83, first ejaculation HR=0.62, 95%CI=0.49-0.78, external genitalia development HR=0.70, 95%CI=0.56-0.87, pubic hair development HR=0.66, 95%CI=0.54-0.80). The left-behind boys later observed testicular development (HR=0.74, 95%CI=0.57-0.96), first ejaculation (HR=0.71, 95%CI=0.50-0.99) and pubic hair development (HR=0.68, 95%CI=0.51-0.91). Testicular development (HR=1.26, 95%CI=1.01-1.58) was observed earlier in boys who felt their parents were close (P<0.05). The results of multivariate analysis showed that the timing of pubic hair development was later in floating girls (HR=0.79, 95%CI=0.65-0.96), and family factors had nothing to do with the puberty timing in boys. Conclusion In the study, left behind children, self-perceived of parents relationship and family economic conditions are the influencing factors of children’s puberty timing. However, after adjusted for age and BMI, this association was mainly found in pubic hair of girls. The association between family factors and other pubertal development events still needs to be confirmed by further follow-up investigation.

Objective: To analyze the characteristics of puberty growth of boys and to explore the relationship between puberty growth and sexual development of boys. Methods: Pubertal development of boys from grade 1 to grade 4 in Jiulongpo district of Chongqing was followed up once every six months. The data of height, weight, BMI, the age of first ejaculation and testicular development of boys from baseline to follow-up every 6 months for 5 years were analyzed. Based on peak height velocity (PHV), the average level of PHV and age at peak height velocity(PHA) were analyzed. ANOVA was used to compare the height growth rate of boys in different age groups before and after the first ejaculation. Kendall rank correlation was used to analyze the relationship between different stages of testicular development and BMI. Results: The mean age of PHA was (11.72±1.03) years in adolescent height speed cohort, and the mean age of first ejaculation was (12.45±0.98) years before and after the first ejaculation cohort. There was significant difference in the increment of height before and after one year of the age of first ejaculation (P<0.05), the younger the age of the first ejaculation, the greater increase of height in the following year. The height, weight, BMI of boys aged 11 to 14 years were positively correlated with testicular volume(P<0.05). Conclusion The height growth of boys reached its peak one year before the first ejaculation, and began to decrease after first ejaculation, and the age of the first ejaculation of boys was negatively correlated with the increment of height in the following year, while the testicular development of boys was positively correlated with height, weight and BMI.

Objective: Longitudinal data were used in this study to examine the predictive effects of psychological stress in early puberty on subsequent anxiety and depression symptoms. Methods: Objects from a puberty cohort of 998 children from 4 primary schools in Chongqing were included. Psychological stress was measured during their early puberty, and anxiety and depression were followed up after 4 years. Multiple linear regression was used to analyze the influence of psychological stress on anxiety and depression level in their middle puberty. Results: The average score of psychological stress during early puberty was (34.79±24.78), and scores of anxiety and depression were (11.20±10.89) and (12.06±6.69), respectively, with detection rates of 14.03% and 15.63%. Girls had higher anxiety and depression scores than boys(F=51.58,5.48，P<0.05). The depression scores of children with different parents’ educational levelsand perceived parental relationship were different(F=6.74, 7.38, 10.49, P<0.05). The results of multiple linear regression showed that girls(β=4.38), higher psychological stress(β=0.13), older age (β=0.89) were risk factors for higher anxiety level. Children with higher psychological stress(β=0.05), older age(β=0.57), perceived worse parents’ relationship(β=1.19), lower maternal education (β=-1.00) had higher depression scores(P<0.05). Conclusion The psychological stress level, and age during early puberty had a positive predictive effect on anxiety and depression after 4 years. Simultaneously, girls were more prone to anxiety, and poor parental relationship and low maternal literacy were risk factors for children’s depression.