medwireNews: The incidences of central precocious puberty (CPP) and normal variant puberty have risen over the past 20 years, in line with overall population trends for earlier puberty in both girls and boys, say researchers.
The team previously found no shift in the incidence of CPP between 1993 and 2001 in girls or boys. But their new study, encompassing 8596 Danish children with diagnoses of CPP, premature thelarche (PT) or premature adrenarche (PA), reveals a two- to threefold increased incidence over a 20-year period from 1998 to 2017.
Anders Juul (University of Copenhagen, Denmark) and co-researchers say this is consistent with research showing that the age at pubertal onset is becoming generally younger, citing “a global reduction of 3 months per decade” in one previous analysis of girls.
“There may be basis for revision of reference ranges for pubertal onset based on new thorough clinical investigations of CPP diagnosis and interrelation with bone age advancement and hormonal changes in the general population”, they write in JAMA Network Open.
The children in the current study were identified from a national register, had been diagnosed at a median of 8.0 years old, and the vast majority (90.4%) were girls. Across the 20-year study period the average annual rates per 10,000 children were 9.2, 1.1 and 1.3 for CPP, PT and PA, respectively, in girls and 0.9 and 0.2 for CPP and PA, respectively, in boys. Among girls, CPP rates were markedly higher in immigrant children than in native Danes.
Among girls of Danish origin, the annual rate of CPP per 10,000 girls rose sixfold from 2.6 to 14.6 in 1998 and 2017, respectively. The rate of PT rose 33-fold, from 0.07 to 2.24 per 10,000 girls, and the rate of PA rose 18-fold from 0.16 to 2.96 per 10,000 girls.
The same trend was evident in boys of Danish origin, with the rate of CPP rising 15-fold, from 0.1 to 2.1 per 10,000 boys, although the incidence of CPP in 2017 was ninefold higher in girls than boys.
The researchers describe their findings as “deeply concerning”, first, because current criteria for the diagnosis of precocious puberty are based on population norms that may not be appropriate for contemporary children. This may lead to overdiagnosis and unneeded treatment, with the potential for adverse psychosocial effects, they say.
“Second, an increasing incidence of premature sexual development in younger girls potentially is associated with adverse implications for long-term health”, write Juul and team.
“Third, secular trends across populations in the onset of puberty without a clear indication of the underlying mechanism is concerning, given that there are no evidence-based preventive interventions available. The mechanisms underlying this increasing trend in incidence of CPP and its benign variants reported here are uncertain.”
By Eleanor McDermid
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JAMA Netw Open 2020; 3: e2015665