儿童青春期发育延迟的确切患病率和发病率尚不明确。大部分患者为男孩。在美国,原发性闭经的患病率 < 0.1%,[1]Timmreck LS, Reindollar RH. Contemporary issues in primary amenorrhea. Obstet Gynecol Clin North Am. 2003;30:287-302.http://www.ncbi.nlm.nih.gov/pubmed/12836721?tool=bestpractice.com活产女婴患 Turner 综合征的患病率为 1/2500,[2]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;87:81-83.http://www.ncbi.nlm.nih.gov/pubmed/2037286?tool=bestpractice.com[3]Jacobs PA, Melville M, Ratcliffe S, et al. A cytogenetic survey of 11,680 newborn infants. Ann Hum Genet. 1974;37:359-376.http://www.ncbi.nlm.nih.gov/pubmed/4277977?tool=bestpractice.com而活产男婴 Klinefelter 综合征的患病率为 1/1500。
由于存在多种混杂因素,导致难以估计发病率和患病率。[4]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
相关证据显示,如果青春期被定义为月经初潮年龄,则女孩进入青春期的年龄在[5]Tanner JM. Trend towards earlier menarche in London, Oslo, Copenhagen, the Netherlands and Hungary. Nature. 1973;243:95-96.http://www.ncbi.nlm.nih.gov/pubmed/4706636?tool=bestpractice.com[6]Biro FM, Khoury P, Morrison JA. Influence of obesity on timing of puberty. Int J Androl. 2006;29:272-277.http://www.ncbi.nlm.nih.gov/pubmed/16371114?tool=bestpractice.com连续几代中越来越趋于早龄化(每十年提前 2 至 3 个月)。几乎无证据显示男孩进入青春期的年龄会随着时间改变,[7]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;24:435-452.http://www.ncbi.nlm.nih.gov/pubmed/9300121?tool=bestpractice.com[8]Mul D, Fredriks AM, van Buuren S, et al. Pubertal development in The Netherlands 1965-1997. Pediatr Res. 2001;50:479-486.http://www.ncbi.nlm.nih.gov/pubmed/11568291?tool=bestpractice.com其可能原因是与女孩初潮的文件记录相比,男孩青春期开始和完成的时间无较明确的定义和文件记录。
不同种族群体的平均青春期年龄不同。黑人女孩的平均初潮年龄为 12.2 岁,而白人女孩的平均初潮年龄为 12.9 岁。
遗传因素对青春期开始的时间有影响,表现为母女之间青春期开始的年龄相似,尤其是月经初潮的年龄。
自 1980 年以来,儿童肥胖的发生率已增加一倍,[9]Ogden CL, Carroll MD, Flegal KM. High body mass index for age among US children and adolescents, 2003-2006. JAMA. 2008;299:2401-2405.http://jama.jamanetwork.com/article.aspx?articleid=1028638http://www.ncbi.nlm.nih.gov/pubmed/18505949?tool=bestpractice.com中度肥胖与初潮年龄提前有关。[6]Biro FM, Khoury P, Morrison JA. Influence of obesity on timing of puberty. Int J Androl. 2006;29:272-277.http://www.ncbi.nlm.nih.gov/pubmed/16371114?tool=bestpractice.com[10]Osler DC, Crawford JD. Examination of the hypothesis of a critical weight at menarche in ambulatory and bedridden mentally retarded girls. Pediatrics. 1973;51:675-679.http://www.ncbi.nlm.nih.gov/pubmed/4697516?tool=bestpractice.com
一项包括 232 名青春期延迟青少年(158 名男孩;74 名女孩)的大型回顾性研究发现,推定性体质性青春期延迟最为常见(53%;男女比值约为 2:1)。[11]Sedlmeyer IL, Palmert MR. Delayed puberty: analysis of a large case series from an academic center. J Clin Endocrinol Metab. 2002;87:1613-1620.http://press.endocrine.org/doi/full/10.1210/jcem.87.4.8395http://www.ncbi.nlm.nih.gov/pubmed/11932291?tool=bestpractice.com另有 19% 的患者可随时间出现自发性青春期发育。据报道,器质性低促性腺激素性腺功能减退和高促性腺激素性腺功能减退所占比例分别为 12% 和 13%。[11]Sedlmeyer IL, Palmert MR. Delayed puberty: analysis of a large case series from an academic center. J Clin Endocrinol Metab. 2002;87:1613-1620.http://press.endocrine.org/doi/full/10.1210/jcem.87.4.8395http://www.ncbi.nlm.nih.gov/pubmed/11932291?tool=bestpractice.com