title: Persistent impact of pubertal timing on trends in smoking, food choice, activity, and stress in adolescence.
abstract: OBJECTIVE
  a) To replicate the established association between early puberty and smoking; b) to see whether differences between early and late maturers narrowed with increasing age and differed by gender; and c) to determine whether other health behaviors (food choice, physical activity, sedentary behavior) and stress showed the same association with pubertal timing.
  
  
  METHODS
  The Health and Behaviour in Teenagers Study (HABITS) followed a cohort of 5863 adolescents from ages 11 to 12 years (UK year 7; US grade 6) for 5 years. Puberty was assessed with the Pubertal Development Scale. Three pubertal timing groups were created by identifying adolescents who reached midpuberty relatively early, average, or late, compared with their peers. Longitudinal trends in health behaviors and stress were compared between the three groups.
  
  
  RESULTS
  Smoking rates were higher throughout adolescence among early-maturing students, with no evidence that late-maturers "caught up" when they reached puberty, although group differences narrowed over time. Early-maturing students had higher rates of sedentary behaviors but also reported higher rates of vigorous activity than their "on-time" developing counterparts. Patterns in dietary behaviors and stress showed lower rates of daily breakfast and higher stress among early-maturing girls, but not boys. Overall, the effects were largest in early adolescence (ages 11-13 years) and became smaller at older ages (ages 14-16 years).
  
  
  CONCLUSIONS
  Early-maturing adolescents are at increased risk for unhealthy behaviors, especially smoking, and although differences attenuate during adolescence, they remain significant at age 16 years. This suggests that early maturation may be a cause of, or is at least a marker for, differences in lifestyle.
authors.affiliation: Cancer Research UK Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, Gower Street, London WC1E 6BT, UK. c.jaarsveld@ucl.ac.uk
authors.forename: Cornelia H M
authors.initials: CH
authors.lastname: van Jaarsveld
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Fidler
authors.forename: Alice E
authors.initials: AE
authors.lastname: Simon
authors.forename: Jane
authors.initials: J
authors.lastname: Wardle
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D015331:Cohort Studies; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D011627:Puberty / Q000523:psychology*; D012907:Smoking / Q000453:epidemiology*; D013315:Stress, Psychological