Breast Development, Puberty Starting Earlier in Girls Worldwide
Age at pubertal onset decreased almost three months per decade from 1977 to 2013; earliest onset in the U.S.
TUESDAY, Feb. 11, 2020 (HealthDay News) -- Across the world, young women are entering puberty at increasingly earlier ages, according to a review published online Feb. 10 in JAMA Pediatrics.
Camilla Eckert-Lind, from Rigshospitalet and the University of Copenhagen in Denmark, and colleagues conducted a systematic review of 3,602 studies that examined the age at onset of breast gland development (thelarche) in healthy girls from regions across the world. A total of 38 articles qualified for systematic review, and 30 were used for a metaregression analysis to characterize pubertal onset over time.
The researchers found that pubertal onset, as indicated by thelarche, decreased by 0.24 years per decade between 1977 and 2013. The median age at Tanner breast stage 2, the indicator for thelarche, ranged from 8.8 to 10.3 years in the United States (earliest onset) and from 10.1 to 13.2 years in Africa (latest onset).
"In this comprehensive systematic review with meta-analysis, we show for the first time, to our knowledge, that age at pubertal onset based on thelarche has decreased by almost three months per decade from 1977 to 2013," the authors write. "A younger age at pubertal onset may change current diagnostic decision making. The medical community needs current and relevant data to redefine 'precocious puberty,' because the traditional definition may be outdated, at least in some regions of the world."