title: Pubertal development in girls: secular trends.
abstract: OBJECTIVE
  To provide an overview of recent studies from the US and other parts of the world that provide conflicting data as to whether there has been a secular trend for earlier onset of puberty and menarche from about 1960 to the present.
  
  
  RESULTS
  Studies from the US suggest a decrease in the age of onset of puberty over the past 40 years of between 0.5 and 1.0 years, with black girls maturing 0.5 to 1 year earlier than white girls. There has been a smaller decrease in the mean age at menarche, on the order of 0.2 years. Northern European countries have not reported such a trend, but several other countries have. The most likely explanation for this trend is an increase in the prevalence of obesity in children.
  
  
  CONCLUSIONS
  In light of the above trends, the view that onset of any pubertal changes prior to age 8 years requires an extensive evaluation should be reevaluated. The majority of such early-maturing girls are normal girls at the early end of the age distribution for pubertal onset. As much attention should be paid to the rate of progression of pubertal findings as to their age of appearance.
authors.affiliation: Children's National Medical Center, Washington, DC 20010, USA. pkaplowi@cnmc.org
authors.forename: Paul
authors.initials: P
authors.lastname: Kaplowitz
mesh_terms: D000293:Adolescent; D001741:Black or African American / Q000706:statistics & numerical data; D017668:Age of Onset; D002648:Child; D005260:Female; D006801:Humans; D008572:Menarche / Q000502:physiology*; D009765:Obesity / Q000453:epidemiology / Q000503:physiopathology*; D015995:Prevalence; D011627:Puberty / Q000502:physiology*; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data