title: Early Life Growth Predicts Pubertal Development in South African Adolescents.
abstract: BACKGROUND
  Given global trends toward earlier onset of puberty and the adverse psychosocial consequences of early puberty, it is important to understand the childhood predictors of pubertal timing and tempo.
  
  
  OBJECTIVE
  We examined the association between early growth and the timing and tempo of puberty in adolescents in South Africa.
  
  
  METHODS
  We analyzed prospectively collected data from 1060 boys and 1135 girls participating in the Birth-to-Twenty cohort in Soweto, South Africa. Height-for-age z scores (HAZs) and body mass index-for-age z scores (BMIZs) were calculated based on height (centimeters) and body mass index (kilograms per meter squared) at ages 5 y and 8 y. The development of genitals, breasts, and pubic hair was recorded annually from 9 to 16 y of age with the use of the Tanner sexual maturation scale (SMS). We used latent class growth analysis to identify pubertal trajectory classes and also characterized children as fast or slow developers based on the SMS score at 12 y of age. We used multinomial logistic regression to estimate associations of HAZ and BMIZ at ages 5 and 8 y with pubertal development.
  
  
  RESULTS
  We identified 3 classes for pubic hair development (for both girls and boys) and 4 classes for breast (for girls) and genital (for boys) development. In girls, both HAZ and BMIZ at age 5 y were positively associated with pubic hair development [relative risk ratio (RRR): 1.57, P < 0.001 and RRR: 1.51, P < 0.01, respectively], as was BMI at age 8 y (RRR: 2.06, P = 0.03); similar findings were observed for breast development. In boys, HAZ and BMIZ at age 5 y were positively associated with pubic hair development (RRR: 1.78, P < 0.001 and RRR: 1.43, P < 0.01, respectively); HAZ at age 5 y was associated with development of genitals (RRR: 2.19, P < 0.01).
  
  
  CONCLUSIONS
  In boys and girls, both height and body mass index in early childhood predicted the trajectory of pubertal development. This may provide a tool to identify children at risk of early pubertal onset.
authors: Nutrition and Health Sciences Program, Laney Graduate School, and Medical Research Council (MRC) Developmental Pathways for Health Research Unit, and.
authors: Elizabeth A
authors: http://orcid.org/0000-0002-4249-8455
authors: EA
authors: Lundeen
authors: Medical Research Council (MRC) Developmental Pathways for Health Research Unit, and Department of Science and Technology - National Research Foundation (DST-NRF) Centre of Excellence of Human Development, University of the Witwatersrand, Johannesburg, South Africa.
authors: Shane A
authors: SA
authors: Norris
authors: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA; and.
authors: Reynaldo
authors: R
authors: Martorell
authors: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA; and.
authors: Parminder S
authors: http://orcid.org/0000-0002-0350-3469
authors: PS
authors: Suchdev
authors: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA; and.
authors: Neil K
authors: NK
authors: Mehta
authors: Medical Research Council (MRC) Developmental Pathways for Health Research Unit, and Department of Science and Technology - National Research Foundation (DST-NRF) Centre of Excellence of Human Development, University of the Witwatersrand, Johannesburg, South Africa.
authors: Linda M
authors: LM
authors: Richter
authors: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA; and Medical Research Council (MRC) Developmental Pathways for Health Research Unit, and aryeh.stein@emory.edu.
authors: Aryeh D
authors: http://orcid.org/0000-0003-1138-6458
authors: AD
authors: Stein
mesh_terms: D000293:Adolescent; D044383:Black People; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D011627:Puberty; D013019:South Africa
keywords: adolescent; body mass index; child growth; latent class growth analysis; puberty