ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: JAMA Pediatr. 2020;174(4):e195881. doi: 10.1001/jamapediatrics.2019.5881

• The authors evaluated the change in pubertal onset in healthy girls around the world based on age at thelarche.• Overall, the age at thelarche decreased 0.24 years per decade from 1977 to 2013.• This decrease seems to reflect a worldwide trend.

The authors focus on the change in the age of apparition of breast development in girls living in different parts of the world. Despite many limitations that are expected in a meta-analysis of published studies, they show a worldwide decrease in the age of thelarche of about 3 months per decade. This is consistent with the decrease in the age of menarche of 2–6 months per decade reported in many countries around the world over the last 40 years, including India, China, Ghana, and Korea. A major cause for this earlier activation of the hypothalamo-pituitary-gonadal axis is thought to be improved nutrition in children and, in particular in the United States, a major increase in the prevalence of obesity. The common link seems to be an increased production of leptin by the adipose tissue which in turns activates the hormonal cascade leading to the development of puberty. However, the role of endocrine disruptors, rarely measured in low-resource settings, is also postulated. The present article also finds that the mean age at thelarche ranged from 9.8 to 10.8 years in Europe, 9.7 to 10.3 years in the Middle East, 8.9 to 11.5 years in Asia, 8.8 to 10.3 years in the United States, and 10.1 to 13.2 years in Africa. From a clinical point of view, these data have implications on the use of diagnostic and therapeutic agents, in particular in low-resource settings where healthcare funding is limited. Traditional recommendations include determination of basal or stimulated LH and FSH, MRI of the hypothalamo-pituitary region, bone age and pelvic ultrasound to rule out an underlying condition in girls presenting with precocious puberty. However, pediatric endocrinologists know that in the vast majority of the cases, the final diagnosis will be idiopathic central precocious puberty. This suggests that the age at which evaluation of the child with precocious puberty should be considered should be adapted to the local characteristics and that evaluation should rely on clinical examination and follow up, with investigations performed only in children who are at high risk of an underlying condition.