Timing of spermarche and menarche among urban students in Guangzhou, China: trends from 2005 to 2012 and association with Obesity

Abstract

In Guangzhou, China, whether the trend of a decreasing pubertal age has continued in recent years remained unknown, and the association between obesity and early puberty was still controversial. Herein, we conducted a serial cross-sectional study using data from physical fitness surveillance (2005–2012), to determine the recent trends in age at spermarche and menarche among students in Guangzhou, and to investigate whether elevated BMI modified timing of spermarche and menarche. This study included 1,278,258 urban students. In boys, no significant differences were observed in median ages of spermarche (MAS) from 2005 to 2012, with overlapping 95% CIs. Similar results were observed for median ages of menarche (MAM) in girls. The Cox-Stuart trend test showed neither upward nor downward shift in MAS and MAM over time (P = 0.625; 1.000). Each year, both MAS and MAM decreased with increasing BMI. Furthermore, a higher BMI was associated with early age at spermarche and menarche, with ORs of 1.052 (95% CI = 1.045–1.059) and 1.233 (95% CI = 1.220–1.247) in 2012 for boys and girls, respectively. In conclusion, the pubertal timing has been stable in urban students from 2005 to 2012. Furthermore, obesity was associated with early timing of spermarche and menarche.

Adipokines: A gear shift in puberty

“…According to results from studies reported in Table , girls with obesity enter puberty earlier compared with girls with normal weight . An explanation for the early onset of puberty in these girls might be found in the secretion of adipokines.…”

“…The association between obesity and puberty onset in boys is rather controversial compared with findings in girls. Most studies reported an early onset of puberty in boys associated with increased BMI, while others reported no associations at all or a delayed onset of puberty (Table ) . The presence of excessive adipose tissue can be involved in puberty onset in boys as the secretion of adipokines can modulate both adrenarche and gonadarche.…”

“…leptin. Thereby, differences in puberty measurements could explain variations in the age of puberty onset between boys and girls within different studies or across continents, countries, and ethnicities (Figure ) . In addition, the inclusion of a proper age range (8‐16 years) is important when assessing the onset of puberty .…”

“…Additionally, it is important that all studies use the same anthropometric standards and sex‐specific cut‐offs . Specifically in children, BMI is often dependent on age and growth spurts . Thereby, BMI is a less accurate measurement in case of growth spurts .…”

“…they develop sexual characteristics and obtain reproductive functions . Although many studies have shown associations between obesity and puberty, the biological mechanisms underlying obesity and puberty onset remain unclear. Hereafter, we review in detail the role of adipokines in the onset of puberty in childhood obesity.…”