A new study from Rigshospitalet shows that not only Danish girls, but girls all over the world are reaching puberty earlier.
Many research studies have shown that Danish girls are entering puberty earlier than previously. The research showed that, in 1991, girls were entering puberty at around 11 years old, and in 2005 girls were just under 10 years old.
These remarkable findings from Denmark have now been confirmed by a new study from Rigshospitalet, which also applies for the rest of the world.
After reviewing and meta-analysing more than 1,500 scientific articles, a team from Rigshospitalet headed by Camilla Eckert-Lind could conclude that the age of the onset of female puberty throughout the world has fallen by 0.33 years every decade from 1977 to the present.
The article was published on 10 February in the prestigious scientific journal, JAMA Pediatrics.
The reason for the earlier onset of puberty is not clear, as the first author and researcher at the Department of Growth and Reproduction, Camilla Eckert-Lind explained:
“We don’t know why girls are starting puberty earlier. We have a suspicion that increasing obesity and exposure to endocrine-disrupting substances in the environment may play an important role, but we can’t prove any direct link.”
Professor Anders Juul, who is behind the study, finds the results disturbing, and stresses that there is a need for more research to establish whether there are grounds to redefine both the concept of puberty, and when a child is considered as being in “early puberty”.
Anders Juul explains,
"It’s worrying that our children are becoming sexually mature earlier and earlier, and we don’t know why. In practice, this means we have to redefine what is normal.
Today, we examine girls younger than eight years with signs of puberty using hormone tests and MRI head scans to rule out diseases. However, the eight-year limit should be moved downwards in light of our current knowledge and research, as well as the new study,” he said.
"We have strong need for a new study to determine the lower limits for normal puberty for Danish girls in 2020, and thereby which girls should be examined, and which are merely healthy and more mature early on,” Anders Juul concluded.
Read the original article in JAMA Pediatrics.