Recent pubertal timing trends in Northern Taiwanese children: Comparison with skeletal maturity

Abstract

Background: International studies have reported an early age of onset of puberty in girls and boys. However, the current situation of puberty onset in Taiwanese children is unknown. In this study, the timing of menarche and pubertal change in testicular volume (TV) in Taiwanese children was examined, and bone age (BA) was used as an internal somatic maturity scale and compared with the chronological age (CA) at pubertal timing.

Methods: Clinical data from October 1, 2010, to March 31, 2018, were retrospectively collected from a general hospital in Taipei. The data of patients who were diagnosed with endocrine/genetic disorders were excluded. Clinical data included CA, timing of menarche, and X-ray images of TV and BA. BA was determined by a senior pediatrician and a senior pediatric radiologist. The reliability and validity of BA readings were tested. Collected data were analyzed statistically.

Results: Overall, TV records of 241 boys and the menarche timing data of 98 girls were collected from 1823 children. CA for menarche was 11.35 ± 1.06 years (mean ± SD), and BA for menarche was 12.95 ± 0.80 years. CA and BA at TV = 15 mL in male puberty was 12.32 ± 1.22 and 13.46 ± 0.68 years, respectively. A stronger correlation was observed between TV and BA than between TV and CA during the pubertal period.

Conclusion: The secular trend of earlier puberty timing continues. The decline rate of menarche timing was approximately 0.43 years per decade in the past 30 years. Among boys, an advance of more than 1 year in pubertal timing age was observed over the past 20 years. BA and TV showed high correlation during puberty.

Fig. 1

Flowchart of the selection process. BA = bone age; OPD = outpatient department; TV = testicular volume.

Fig. 2

Recent pubertal timing in Northern Taiwanese children. A, Comparison of age at menarche between chronological age (CA) and bone age (BA) in girls (n = 98). The mean CA was 11.35 ± 1.06 years, and the mean BA was 12.95 ± 0.80 years; p < 0.001. B, Comparison of age at the start and middle of puberty between CA and BA in boys. When testicular volume (TV) was 4 mL (n = 21), the mean CA was 9.50 ± 1.38 years, and the mean BA was 9.04 ± 1.28 years; p = 0.119. When size of TV was 15 mL (n = 19), the mean CA was 12.32 ± 1.22 years, and the mean BA was 13.46 ± 0.68 years; p value = 0.001.

Fig. 3

Testicular volume (TV) versus chronological age (CA) or bone age (BA) (n = 241). Group 1: age <9.5 years, group 2: age 9.5–15 years, and group 3: age >15 years. A, The correlation between TV and chronological age. B, The correlation between TV and bone age.

Fig. 4

Correlation between mean ages of menarche among girls in different studies in Taiwan.