What are the global trends in the incidence of precocious puberty?

Updated: Nov 30, 2020
  • Author: Paul B Kaplowitz, MD, PhD; Chief Editor: Robert P Hoffman, MD  more...
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A 2003 review of trends in timing of puberty around the world showed no clear progression toward earlier puberty in northern Europe. However, earlier mean age of menarche has been reported in some southern European countries and other warmer parts of the world. [9]  A Danish study showed that over a 15-year period (1991-1993 vs 2000-2008), the mean age at which breast tissue appeared in girls decreased from age 10.88 years to 9.86 years, with a much smaller decline in the mean age at menarche (age 13.42 y vs age 13.13 y). [10]  A study of over 20,000 girls from urban China performed from 2003-2005 showed that the mean age of breast development was 9.2 years, with the mean age at menarche falling to 12.27 years; about 20% of girls aged 8 years already had evidence of breast development. [11]  Thus, in certain parts of the world, a decline in the age of puberty in girls has been noted, with parallel changes seen in US females. Similarly, a literature review by Eckert-Lind et al indicated that worldwide, from 1977 to 2013, the mean age of thelarche fell by a mean of nearly 3 months per decade. The investigators therefore state that at least in some parts of the world, precocious puberty needs to be redefined. [12]

An interesting and still unexplained finding is the high incidence of precocious puberty in girls adopted into Western Europe from various underdeveloped countries. This has been studied extensively in Denmark, where the mean age at thelarche and at menarche in internationally adopted girls was significantly lower than that observed in a reference group of Danish-born girls. [13]  Exposure to chemicals in the environment has been proposed as the cause, but the fact that LH, FSH, and estradiol levels rise earlier in adopted girls suggests that their earlier puberty is centrally mediated and not chemically induced. A commentary published in 2013 suggested that frequent underreporting of age of adoptees from certain countries such as China may be the real explanation for this phenomenon. [14]


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