title: Infant growth and onset of puberty: prospective observations from Hong Kong's "Children of 1997" birth cohort.
abstract: OBJECTIVE
  Infant growth and early puberty are associated with the risk of cardiovascular disease. It is unclear whether pubertal timing has an independent etiologic role or is a marker of preceding growth. We examined whether infant growth was associated with age at pubertal onset and whether any associations were mediated by childhood height or body mass index.
  
  
  METHODS
  We used multivariable interval-censored proportional hazards regression in 6873 term births (87% follow-up, 53% male) from a population-representative Hong Kong Chinese birth cohort, "Children of 1997." We examined the adjusted associations of sex-specific infant growth trajectories, derived from latent class analyses by the use of, on average, 4.2 measurements per child, with clinically assessed age at pubertal onset (Tanner stage II). We used Sobel tests to assess mediation.
  
  
  RESULTS
  Compared with children of average birth weight whose weight followed the same centile curve, a faster weight growth trajectory from birth to 12 months was associated with earlier pubertal onset (time ratio, 0.979; 95% confidence interval, 0.965-0.993) among boys, whereas girls born light with slow infant growth had later puberty (time ratio 1.020, 95% confidence interval 1.006-1.034). These associations were mediated by both height and body mass index among girls but only by height in boys.
  
  
  CONCLUSIONS
  Infant weight growth may be associated with earlier pubertal onset, particularly in boys, at least in part because it is associated with more linear growth in childhood. Earlier pubertal onset may be an indicator of up-regulation of growth axes related to the risk of cardiovascular disease.
authors: Lifestyle and Lifecourse Epidemiology Group, School of Public Health, The University of Hong Kong.
authors: L L
authors: LL
authors: Hui
authors: Man-Yu
authors: MY
authors: Wong
authors: Tai Hing
authors: TH
authors: Lam
authors: Gabriel M
authors: GM
authors: Leung
authors: C Mary
authors: CM
authors: Schooling
mesh_terms: D001827:Body Height; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology; D002648:Child; D002657:Child Development; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D016016:Proportional Hazards Models; D011627:Puberty / Q000502:physiology*; D012307:Risk Factors