The critical BMI hypothesis for puberty initiation and the gender prevalence difference: Evidence from an epidemiological survey in Beijing, China

Abstract

BackgroundAlthough previous studies suggested that there is a certain level of body fat mass before puberty can be initiated, most studies have focused on girls.ObjectiveTo investigate the relationship between precocious puberty and physical growth in school-aged children in Beijing, China.Methods7590 Chinese children (3591 girls and 3999 boys) aged 6–11 years were recruited in Beijing, China. Body mass index (BMI) categories were defined by WHO Child Growth Standards and central obesity were defined by sex-specific waist-to-height ratio cut-offs (≥0.46 for girls, ≥0.48 for boys). Sexual development was assessed using Tanner criteria.ResultsThe prevalence of general obesity and central obesity among boys was higher than that in girls. Girls had a significantly higher precocious puberty rate than boys (5.93% vs. 0.87%), particularly in those aged 7 years old (9.20%). Children in the general obesity and central obesity groups have a higher prevalence of precocious puberty and earlier median ages for the attainment of Tanner B2/T2. For girls with Tanner stages≥II at 6-year-old and 7-year-old, the mean BMI was equivalent to the 50th centile of a normal 9.9-year-old and 11.9-year-old girl, respectively. The mean BMI of boys with Tanner stages≥II at 7-year-old and 8-year-old was correspondent to the 50th centile of a normal 14-year-old and 15.3-year-old boy, respectively. For girls, general obesity appears to contribute to the risk of the development of precocious puberty to a greater extent than central obesity does. For boys, central obesity, but not general obesity, was an independent risk factor for precocious puberty.ConclusionsThe prevalence of childhood obesity and precocious puberty was high in China. Precocious puberty was correlated with a large BMI. Boys had a higher threshold of BMI for puberty development than girls. Children with precocious puberty, particularly those with central obesity, should be aware of adverse cardiovascular events.

Association between precocious puberty and obesity risk in children: a systematic review and meta-analysis

“…Our findings confirm the results of previous reports suggesting that precocious puberty is associated with an increased risk of obesity in girls, while the relationship between precocious puberty and obesity in boys remains inconclusive according to previous studies ( 25 , 36 , 37 ). Previous studies have also shown that boys with precocious puberty are associated with a higher BMI, although the BMI threshold for puberty development in boys is higher than that in girls ( 38 ). During pubertal development, significant sex differences exist between obese girls and boys, with increased peripheral conversion of low-potency androgens to estrogens by adipose tissue-aromatase and increased insulin resistance being two potential contributing factors ( 39 ).…”

Is early or late biological maturation trigger obesity? A machine learning modeling research in Turkey boys and girls

“…This controversial results would be attributed to the study design, evaluation technique different populations studied and study duration. In justifying the obtained results for boys, it should be noted that there are conflictary results regarding the relationship between obesity and timing of pubertal onset in boys ( 40 , 41 ) and this can be a reason for low correlation of obesity and maturity in boys rather than girls. In other words, obesity would contribute to early onset of puberty in girls more than boys.…”

“…In other words, obesity would contribute to early onset of puberty in girls more than boys. One possible reason for this effect refers to higher threshold of BMI for puberty development in boys than girls ( 41 ). The second aim was to examine the effects of anthropometric measurements, gender, and obesity on biological maturation in adolescents.…”