Timing of puberty in boys and girls: A population‐based study

Abstract

Background A secular trend towards earlier puberty has been observed in girls, while a similar trend has been more uncertain in boys. We estimated current ages at pubertal development in both boys and girls. Methods In this population‐based cohort study, 14 759 of 22 439 invited boys and girls born from 2000 to 2003 in the Danish National Birth Cohort gave half‐yearly self‐reported information on puberty from the age of 11.5 years and throughout puberty. This late start of follow‐up limits the estimation of age at onset of puberty but not later pubertal milestones. We estimated mean age at attaining the following pubertal milestones in years with 95% confidence intervals ( CI ): age at menarche, voice break, first ejaculation of semen and Tanner stages for pubic hair development and breast development or genital development. Further, the difference in mean age at menarche between mothers and daughters was estimated. Results In boys, voice break occurred at 13.1 (95% CI 13.0, 13.1) years, first ejaculation of semen occurred at 13.4 (95% CI 13.3, 13.4) years, and Tanner Genital Stage 5 occurred at 15.6 (95% CI 15.5, 15.6) years. In girls, age at menarche occurred at 13.0 (95% CI 13.0, 13.1) years and Tanner Breast Stage 5 occurred at 15.8 (95% CI 15.7, 15.9) years. Daughters had menarche 3.6 (95% CI 3.1, 4.2) months earlier than their mothers had. Conclusion These data indicate that age at menarche has declined and to some extent support a decline in age at attaining other markers of pubertal development among boys.

GENETICS IN ENDOCRINOLOGY: Genetic etiologies of central precocious puberty and the role of imprinted genes

“…More recent evaluations in the Copenhagen Puberty Study found earlier age of onset of breast development and slight advancement in age of menarche from children evaluated in the mid-2000s (13). While minor advances in the age of menarche have been observed in the United States and Europe since the 1960s, more dramatic reductions have been observed in countries with improving socioeconomic status such as Indonesia, Brazil, Argentina and China, often in the setting of increased rates of childhood obesity (14,15,16,17,18,19,20). Furthermore, increasing recognition of environmental factors and exposures have been described in association with an earlier age of puberty, such as the effects of maternal smoking during pregnancy, of girls being raised without a father, and of some endocrine-disrupting chemicals (21,22,23).…”

Sex differences in paediatric airway anatomy

“…We found that in a cohort of healthy paediatric patients of varying ages (1–17 years), the large conducting airways were larger in males compared to females after age 14, which correlates with the average time of puberty (Brix et al., 2019; Krieger et al., 2015). Thus, the sex differences in airway size are likely driven by the hormonal changes associated with puberty and are not innate genetic sex differences.…”

Prenatal Exposure to Acetaminophen and Overweight in Childhood

“…The positive association observed for girls at 11 years might indicate a sex‐hormone‐specific mechanism of the exposures , but it could also be explained by the timing of pubertal growth and outcome measures in our study. Some girls might have started entering puberty at age 11, while for most boys, this is still considered a prepubertal period . Another DNBC study that followed a subset of offspring up to age 16 found that prenatal acetaminophen exposure was associated with a 2‐ to 3‐month earlier attainment of several markers of pubertal development (e.g., pubic hair, axillary hair, and acne) only in female offspring .…”