| Purpose To investigate the prevalence of precocious puberty in school-based population in Zhongshan,Guangdong,China,especially in overweight and obese children.Methods We recruited a total of 6696 students aged 6-11 years old from grades 1-3 in 9 selected schools using a multistage stratified cluster random proportional sampling in a population-based cross-sectional study.We measured height,weight,and waist circumference and assessed development of breast and pubic hair in girls,breast development was evaluated by inspection and palpation combined with ultrasound detection for overweight or obese girls,and testicular volume and development of pubic hair in boys.We estimated overall,district-,sex-,and age-specific prevalence of precocious puberty and examined the association between precocious puberty and body mass index(BMI)and between precocious puberty and central obesity.We adjusted the prevalence of precocious puberty by two steps of inverse probability weighting basing on selective attrition in multistage sampling.We used a chi-square test to compare the prevalence difference and Bonferroni to correct for pairwise comparisons among multiple prevalence rates.Results By Tanner stage,the unadjusted prevalence of precocious puberty was 4.74%(95%CI:4.00%-5.47%),2.14%(95%CI:1.52%-2.77%)in urban areas and 9.34%(95%CI:7.66%-11.02%)in suburban areas.The prevalence of precocious puberty in urban areas was lower than that in suburban areas(x2=85.015,p<0.001).The prevalence of precocious puberty in girls and boys was 8.78%(95%CI:7.12%10.44%)and 2.58%(95%CI:1.90%3.26%)respectively.The prevalence of precocious puberty in girls aged 6-7 and 7-8 years old was 7.01%(95%CI:4.74%9.28%)and 10.14%(95%CI:7.79%12.50%),respectively.The prevalence of precocious puberty in boys aged 6-7,7-8 and 8-9 years old was 0.48%(95%CI:-0.06%-1.02%),1.99%(95%CI:1.02%-2.96%)and 5.26%(95%CI:3.56%-6.95%),respectively.The adjusted prevalence of precocious puberty was 6.19%,1.52%in urban areas and 7.72%in suburban areas,and 11.47%in girls and 3.26%in boys.The adjusted prevalence of precocious puberty in girls aged 6-7 and 7-8 years old was 7.80%and 14.82%,respectively.The adjusted prevalence of precocious puberty in boys aged 6-7,7-8 and 8-9 years old was 0.57%,2.65%and 6.43%,respectively.In urban,the prevalence of precocious puberty in normal weight,overweight,and obese group was 2.00%(95%CI:1.26%-2.75%),2.35%(95%CI:0.07%-4.63%)and 8.60%(95%CI:2.90%-14.30%).The prevalence of precocious puberty in normal weight group was lower than that in overweight group(χ2=0.000,p=0.988)and obese group(x2=13.307,p<0.001).In suburban areas,the prevalence of precocious puberty in normal weight,overweight,and obese group was 10.21%(95%CI:7.99%12.43%),21.52%(95%CI:12.46%30.58%)and 24.00%(95%CI:12.16%35.84%),respectively.The prevalence of precocious puberty in normal weight group was lower than that in overweight group(x2=3.923,p=0.048)and obese group(x2=4.452,p=0.035).In girls,the prevalence of precocious puberty in normal weight group was 8.73%(95%CI:6.63%-10.82%),lower than the prevalence 27.94%(95%CI:17.28%-38.61%)in overweight group(x2=24.490,p<0.001)and the prevalence 48.00%(95%CI:28.42%-67.58%)in obese group(χ2=41.063,p<0.001).In boys,the prevalence of precocious puberty in normal weight group was 2.86%(95%CI:1.98%-3.75%),lower than the prevalence 6.78%(95%CI:2.24%-11.32%)in obese group(χ2=4.226,p=0.040).The prevalence of precocious puberty in girls with central obesity(WHtR≥0.46)was 25.93%(95%CI:19.68%-32.17%),higher than the prevalence 5.29%(95%CI:3.85%-6.73%)in girls with non-central obesity(WHtR<0.46)(χ2=83.494,p<0.001).The prevalence of precocious puberty in boys with central obesity(WHtR≥0.48)was 3.34%(95%CI:1.40%-5.29%),higher than the prevalence 2.44%(95%CI:1.72%-3.16%)in boys with non-central obesity(WHtR<0.48)(χ2=0.899,p=0.343).Conclusion The prevalence of precocious puberty in children was 4.74%in Zhongshan,Guangdong,China,and 2.14%(overweight:2.35%;obese:8.60%)in urban areas and 9.34%(overweight:21.52%;obese:24.00%)in suburban areas.The prevalence of precocious puberty in girls with overweight and obese and boys with obese was higher than that in girls and boys with normal weight.The prevalence of precocious puberty in girls with central obesity was higher than that in girls with non-central obesity. |
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