The exact prevalence and incidence of children presenting with a delay in pubertal development is difficult to define. By the definition of pubertal delay as 2 to 2.5 standard deviations later than the population mean age, 2% of the population have delayed puberty, but far fewer have a severely delayed puberty. The majority of patients who present to healthcare professionals are boys. The prevalence of primary amenorrhea in the US is <0.1%,[2]Timmreck LS, Reindollar RH. Contemporary issues in primary amenorrhea. Obstet Gynecol Clin North Am. 2003 Jun;30(2):287-302.
http://www.ncbi.nlm.nih.gov/pubmed/12836721?tool=bestpractice.com
The incidence of Turner syndrome is 1 in 2500 live-born females,[3]Nielsen J, Wohlert M. Chromosome abnormalities found among 34,910 newborn children: results from a 13-year incidence study in Arhus, Denmark. Hum Genet. 1991 May;87(1):81-3.
http://www.ncbi.nlm.nih.gov/pubmed/2037286?tool=bestpractice.com
[4]Jacobs PA, Melville M, Ratcliffe S, et al. A cytogenetic survey of 11,680 newborn infants. Ann Hum Genet. 1974 May;37(4):359-76.
http://www.ncbi.nlm.nih.gov/pubmed/4277977?tool=bestpractice.com
and that of Klinefelter syndrome is 1 in 1500 live-born males. The prevalence of organic hypogonadotropic hypogonadism is 1 in 15,000-50,000.[5]Laitinen EM, Vaaralahti K, Tommiska J, et al. Incidence, phenotypic features and molecular genetics of Kallmann syndrome in Finland. Orphanet J Rare Dis. 2011 Jun 17;6:41.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3143089
http://www.ncbi.nlm.nih.gov/pubmed/21682876?tool=bestpractice.com
The incidence and prevalence of delayed puberty are difficult to estimate because of several confounding factors.[6]Delemarre-van de Waal HA. Secular trend of timing of puberty. Endocr Dev. 2005;8:1-14.
http://www.ncbi.nlm.nih.gov/pubmed/15722614?tool=bestpractice.com
There is evidence that puberty in girls occurs at a progressively earlier age in successive generations (2 to 3 months per decade) if puberty is defined as the age at menarche or by first breast development.[7]Tanner JM. Trend towards earlier menarche in London, Oslo, Copenhagen, the Netherlands and Hungary. Nature. 1973 May 11;243(5402):95-6.
http://www.ncbi.nlm.nih.gov/pubmed/4706636?tool=bestpractice.com
[8]Biro FM, Khoury P, Morrison JA. Influence of obesity on timing of puberty. Int J Androl. 2006 Feb;29(1):272-7.
http://www.ncbi.nlm.nih.gov/pubmed/16371114?tool=bestpractice.com
[9]Aksglaede L, Sørensen K, Petersen JH, et al. Recent decline in age at breast development: the Copenhagen Puberty Study. Pediatrics. 2009 May;123(5):e932-9.
http://www.ncbi.nlm.nih.gov/pubmed/19403485?tool=bestpractice.com
There is more conflicting evidence of the change in the age of onset of puberty over time in boys, although this may be due to the fact that the onset and completion of puberty in boys is less well defined and documented compared with the documentation of menarche in girls.[10]de la Puente ML, Canela J, Alvarez J, et al. Cross-sectional growth study of the child and adolescent population of Catalonia (Spain). Ann Hum Biol. 1997 Sep-Oct;24(5):435-52.
http://www.ncbi.nlm.nih.gov/pubmed/9300121?tool=bestpractice.com
[11]Mul D, Fredriks AM, van Buuren S, et al. Pubertal development in The Netherlands 1965-1997. Pediatr Res. 2001 Oct;50(4):479-86.
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There is a variation in the mean pubertal age between different ethnic groups. Typically, girls of African or Caribbean origin have a younger age of menarche (by approximately 6 months) than white girls.[12]Wu T, Mendola P, Buck GM. Ethnic differences in the presence of secondary sex characteristics and menarche among US girls: the Third National Health and Nutrition Examination Survey, 1988-1994. Pediatrics. 2002 Oct;110(4):752-7.
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The mean age of menarche decreased by 3 months in white girls compared with 5.5 months in girls of African or Caribbean descent between 1960 and 1990 in the US.[13]Himes JH. Examining the evidence for recent secular changes in the timing of puberty in US children in light of increases in the prevalence of obesity. Mol Cell Endocrinol. 2006 Jul 25;(254-55):13-21.
http://www.ncbi.nlm.nih.gov/pubmed/16759793?tool=bestpractice.com
There is a genetic influence on the onset of puberty that manifests as a similarity in the age at onset of puberty, and especially the age of menarche, between twin pairs, sisters, and girls and their mothers.
There has been a doubling in the frequency of obesity in children since 1980; moderate obesity is associated with an earlier age of menarche.[8]Biro FM, Khoury P, Morrison JA. Influence of obesity on timing of puberty. Int J Androl. 2006 Feb;29(1):272-7.
http://www.ncbi.nlm.nih.gov/pubmed/16371114?tool=bestpractice.com
[14]Ogden CL, Carroll MD, Flegal KM. High body mass index for age among US children and adolescents, 2003-2006. JAMA. 2008 May 28;299(20):2401-5.
http://jama.jamanetwork.com/article.aspx?articleid=1028638
http://www.ncbi.nlm.nih.gov/pubmed/18505949?tool=bestpractice.com
[15]Osler DC, Crawford JD. Examination of the hypothesis of a critical weight at menarche in ambulatory and bedridden mentally retarded girls. Pediatrics. 1973 Apr;51(4):675-9.
http://www.ncbi.nlm.nih.gov/pubmed/4697516?tool=bestpractice.com
[16]Day FR, Bulik-Sullivan B, Hinds DA, et al. Shared genetic aetiology of puberty timing between sexes and with health-related outcomes. Nat Commun. 2015 Nov 9;6:8842.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667609
http://www.ncbi.nlm.nih.gov/pubmed/26548314?tool=bestpractice.com
One large retrospective study of 232 adolescents with pubertal delay (158 males; 74 females) found presumed constitutional delay of puberty to be the most common (53%; approximately 2:1 male-to-female ratio).[17]Sedlmeyer IL, Palmert MR. Delayed puberty: analysis of a large case series from an academic center. J Clin Endocrinol Metab. 2002 Apr;87(4):1613-20.
https://academic.oup.com/jcem/article/87/4/1613/2374954?login=false
http://www.ncbi.nlm.nih.gov/pubmed/11932291?tool=bestpractice.com
A further 19% of patients had spontaneous pubertal development with time. Organic hypogonadotropic hypogonadism and hypergonadotropic hypogonadism were reported in 12% and 13% respectively, confirmed in one 2017 study of 244 Finnish children presenting with pubertal delay.[17]Sedlmeyer IL, Palmert MR. Delayed puberty: analysis of a large case series from an academic center. J Clin Endocrinol Metab. 2002 Apr;87(4):1613-20.
https://academic.oup.com/jcem/article/87/4/1613/2374954?login=false
http://www.ncbi.nlm.nih.gov/pubmed/11932291?tool=bestpractice.com
[18]Varimo T, Miettinen PJ, Känsäkoski J, et al. Congenital hypogonadotropic hypogonadism, functional hypogonadotropism or constitutional delay of growth and puberty? An analysis of a large patient series from a single tertiary center. Hum Reprod. 2017 Jan;32(1):147-53.
https://academic.oup.com/humrep/article/32/1/147/2645564?login=false
http://www.ncbi.nlm.nih.gov/pubmed/27927844?tool=bestpractice.com