title: Determinants of weight loss dieting among adolescents: a longitudinal analysis.
abstract: OBJECTIVE
  To prospectively assess characteristics associated with dieting behaviors in adolescence.
  
  
  METHODS
  We analyzed 1,640 adolescents evaluated at 13 and 17 years old (EPITeen cohort), Porto, Portugal. Dieting was assessed only at 17 years, as self-reported frequency of dieting to lose weight in the previous 12 months. The association between participants' characteristics and dieting was summarized using multinomial logistic regression for girls and binary logistic regression for boys.
  
  
  RESULTS
  Dieting at 17 years old was significantly more prevalent in girls than in boys (respectively 27.6% and 10.5% for occasional dieting and 12.2% and 2.6% for frequent dieting). In both sexes, overweight and obese adolescents were significantly more likely to engage in dieting but body dissatisfaction was the strongest determinant among girls. Furthermore, dieting frequency also increased with depressive symptomatology and among those involved in health compromising behaviors.
  
  
  CONCLUSIONS
  Besides body mass index, body image concerns and depressive symptomatology predict dieting throughout adolescence.
authors.affiliation: Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal; Institute of Public Health, University of Porto, Porto, Portugal. Electronic address: vaniamendes@med.up.pt.
authors.forename: Vânia
authors.initials: V
authors.lastname: Mendes
authors.affiliation: Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal; Institute of Public Health, University of Porto, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Araújo
authors.affiliation: Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal; Institute of Public Health, University of Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Lopes
authors.affiliation: Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal; Institute of Public Health, University of Porto, Porto, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Ramos
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D001828:Body Image; D015992:Body Mass Index; D003863:Depression / Q000150:complications*; D004038:Diet, Reducing / Q000523:psychology* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D050177:Overweight / Q000523:psychology
keywords: Adolescents; BMI; Body dissatisfaction; Depressive symptomatology; Dieting; Health-related behaviors