Status survey of sexual development of boys aged 6 to 13 years old from Zhengzhou area / 医学研究生学报

ABSTRACT

Objective Boy sexual development is affected not only by age, but also by environment factors .The present study was to survey and evaluate the status of sexual development in boys from Zhengzhou area and to explore their influencing factors. Methods The height, weight, waist circumference, hip circumference, penis and testicles in 3779 boys aged from 6 to 13 years old in Zhengzhou were measured .The penis length and testicular volume of different ages and their influencing factors were compared, and the beginning age and sexual development characteristics were explored .The development of genitalia and pubes were evaluated by Tanner staging criteria and standards, which were divided into five stages. Results There were 3779 boys, including 395 overweight cases (10.45%) and 208 obesity cases (5.50%).The testicular volume and penis length increased by age, which increased slowly at the age of 6 to 11, followed by a rapid increase after the age of 11 year old.Testicular volume increased more rapidly than that of penis length. The medians quartile of testicular volume in overweight group ,obese group and normal group were 2.50 mL, 2.50 mL, 2.00 mL, 2.00 mL,2.00 mL,1.00 mL respectively .The testicular volume in overweight group and obese group were significantly greater than that in nor -mal group (P<0.01) and there were no difference between overweight group and obese group .The penis length in overweight group and obese group were significantly less than that in normal group (P<0.01), and there was no difference between overweight group and obese group.Testicular volume and penis length were positively correlated with age, height, weight, body mass index, waist circumference and hip circumference; the correlation between testicular volume and height, penis length and age were the strongest. The age of development of testicle (average 12.02 years) in urban area was later by 2.73 years than that in the rural area (average 9.9 years), the difference was statistically significant (P<0.001).The age of pubic development (P2) and maturity (P5) was (12.34 ±0.83) years and (12.39 ±1.24 ) years.The incidence of precocity in boys was 0.40%. Conclusion The sexual development of boys from Zheng-zhou area is similar to the results of large scale survey from China .Attention should be paid to the effect of obesity on sexual develop-ment, and early intervention should be given, the occurrence of adverse events of sexual development can be avoided .