title: Age at Onset of Puberty and Adolescent Depression: "Children of 1997" Birth Cohort.
abstract: Timing of onset of puberty has fallen, with profound and detrimental consequences for health. We examined the associations of earlier onset of puberty with the presence of depression in early to middle adolescence.
  
  
  
  The study examined prospective adjusted associations of age at onset of puberty, based on clinically assessed Tanner stage for breast/genitalia and pubic hair development, and self-reported presence of depression, assessed from the 9-item Patient Health Questionnaire on average at 13.6 years (n = 5795 [73%]). These factors were examined by using multivariable logistic regression in a population-representative Hong Kong Chinese birth cohort (ie, the "Children of 1997"). We also assessed whether associations varied according to gender.
  
  
  
  Association of age at onset of breast/genitalia development with the presence of depression varied according to gender. Earlier onset of breast development was associated with higher risk of the presence of depression (odds ratio, 0.83 per 1 year increase in age of onset [95% confidence interval, 0.70 to 0.98]) adjusted for age, socioeconomic position, mother's place of birth, birth order, secondhand smoke exposure, parental age, survey mode, gender-specific birth weight z score, BMI z score at 7 years, and parental marital status. In boys, similarly adjusted, age at onset of genitalia development was unrelated to the presence of depression. Earlier age at onset of pubic hair development was unrelated to the presence of depression in girls and boys.
  
  
  
  Early onset of breast development was associated with high risk of the presence of depression. Whether these findings are indicators of the effects of hormones or transient effects of social pressures remain to be determined.
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China; and.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China; and.
authors.forename: Shi Lin
authors.initials: SL
authors.lastname: Lin
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China; and.
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China; and Graduate School of Public Health and Health Policy, City University of New York, New York, New York cms1@hku.hk.
authors.forename: C Mary
authors.initials: CM
authors.lastname: Schooling
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001940:Breast / Q000502:physiology; D002648:Child; D003863:Depression / Q000209:etiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D011446:Prospective Studies; D000297:Psychology, Adolescent; D011627:Puberty / Q000523:psychology*; D057566:Self Report; D012737:Sex Factors