[Puberty timing status and its correlation with childhood obesity in Chongqing City]

To investigate the puberty timing status and its correlation with obesity in 8 - 19 year-old students in the urban area of Chongqing.

A total of 3046 primary and middle school students were recruited by using multiple-stage stratified cluster sampling method. The pubertal growth spurt in the students was evaluated by Pubertal Development Scale (PDS), and the physical examination, including body height, weight, the external genitalia, testicular volume and pubic hair of boys, and the breast and pubic hair of girls. The age of each stage was calculated by the method of Probability unit regression, and whether the pubertal start earlier being related to obesity was analyzed by the Spearman rank correlation.

The average age of breast to B2 phase, pubic hair to FP2 phase and the menarche for girls were at 11.51, 13.93 and 12.29 year-old respectively. The average age of genitalia to G2 phase, pubic hair to MP2 phase, the volume of testicular to 4 ml and the first nocturnal emission for boys were at 13.13, 13.62, 11.67 and 13.57 year-old respectively. Among girls, the proportion of overweight or obesity was higher in the earlier puberty group than those in the normal development group, and existing a rank correlation (P < 0.01).

The earlier puberty timing and advanced sexual development were obvious in girls, which may correlate with the factors of obesity.