Study On Status And Related Influencing Factors Of Pubertal Timing Among Children In Guangzhou

Objective: To explore the occurrence status and related factors of pubertal timing among children in Guangzhou, in order to provide scientific evidence for early Pubertal timing prevention and intervention in school and family.Methods: In this cross-sectional study, An randomized sample of the target population whose from 7 to 18 years old completed body check including secondary sexual characteristics, physical examination, physical testing and a questionnaire to obtain information about demographic data, related factors of puberty timing. The median age was used to show the age distribution of all Tanner stages. Subjects were grouped as"early mature"if they reached a certain SM stage earlier than the P₂₅ age for that stage in the population, and as"on time mature"if they reached a certain SM stage between the P₂₅ and P₇₅ age for that stage in the population and we compared the factors (BMI, waist-hip ratio, body fat percentage, urban and rural areas, children of negative emotions, parents working situation, etc) differences between the two groups with T test or Chisq test, multivariable Logistic regression model was used to explore the risk of early pubertal timing.Results: In this survey, the age of target population ranges from 7～18 years old, 53.8% were boys and 46.2% were girls, 47.0% came from urban and 53.0% came from rural. Boys genital development mean age (G2 phase) was 11.6 years (interquartile range: 10.8¹2.5 years). The mean age of pubic hair development (PH2 phase) was 13.0 years (interquartile range:12.2¹3.7 years). First spermarche age was 13.6 years (interquartile range: 13.4¹3.8 years). The mean age of girls breast development (B2 phase) and pubic hair (PH2 phase) was 9.8 years (interquartile range:9.0¹0.4 years) and 11.6 years (interquartile range:10.9¹2.6) respectively. The mean age of menarche was 11.9 years (interquartile range:11.8～12.1 years). Whether boys or girls, Chest circumference, sitting height, vital capacity, grip strength, standing long jump, Sit and Reach in on-time pubertal group have higher than early-timing pubertal group, which is statistically significant(boys P<0.000, girls P<0.000). Waist-hip ratio in early-timing pubertal is significantly higher(boys P<0.000, girls P<0.000)than on-time pubertal group. Children of negative emotions, parents working situation in both girls and boys show no statistical significance among different types of pubertal timing. The results of Unconditional multivariable logistic regression model analysis shown waist-hip ratio(boys OR=1.36, 95%CI 1.03¹.79; girls OR=1.39, 95%CI 1.07¹.80), body fat percentage(girls OR=0.70, 95%CI 0.51⁰.95) and BMI(boys OR=0.50, 95%CI 0.35⁰.72; girls OR=0.58, 95%CI 0.42⁰.80) are major factors to influence the pubertal timing.Conclusions: The puberty timing of chidren in Guangzhou is at early trends. It is obvious that girls are earlier than boys in the puberty timing. Chest circumference, sitting height, vital capacity, grip strength, standing long jump, Sit and Reach in on-time pubertal group have higher than early-timing pubertal group. Waist-hip ratio is greater impaction for the puberty timing. In prepuberty, in order to prevent the early puberty timing of children, they should keep good eating habits, more exercising and keep proper weight(particularly waist-hip ratio).