title: Risk factors of obesity among Brazilian adolescents: a case-control study.
abstract: OBJECTIVE
  To study risk factors associated with overweight and obesity among adolescents enrolled in private high schools in the city of Pelotas, southern Brazil.
  
  
  METHODS
  This was a case-control study. The subjects were 264 overweight (body mass index (BMI) > or =85th percentile of the National Center for Health Statistics (NCHS) reference population) and 264 non-overweight (BMI >5th and <85th NCHS percentiles) adolescents identified by means of an anthropometric survey which included 1608 students. The adolescents were weighed, measured and interviewed about food habits and physical activity at school. Parents provided their own weights and heights when contacted by telephone, and parental BMI was calculated.
  
  
  RESULTS
  Hierarchical multiple conditional logistic regression showed that overweight and obesity were positively associated with mother's (odds ratio (OR) 2.86, 95% confidence interval (Cl) 1.43-5.74) and father's (OR 2.43, 95% Cl 1.37-4.30) BMI >/=30 kg m(-2), being overweight before 10 years of age (OR 2.26, 95% Cl 1.30-3.90) and the habit of dieting (OR 3.53, 95% Cl 1.76-7.22). Having more than three meals per day was found to be a protective factor against overweight and obesity (OR 0.54, 95% Cl 0.29-1.00).
  
  
  CONCLUSIONS
  The present study showed that a family history of obesity, overweight during childhood and the habit of dieting for weight-loss purposes are factors associated with obesity during adolescence. The habit of having more than three daily meals turned out to be a protective factor against overweight. These results suggest the necessity for early intervention at the family and general community levels aimed at the prevention of obesity through actions directed towards the modification of established behaviours.
authors.affiliation: Departamento de Nutrição, Faculdade de Nutrição, Universidade Federal de Pelotas, Campus Universitário, CP 354, Pelotas, RS, CEP 96010-900, Brazil. mneutzli@ufpel.tche.br
authors.forename: Marilda B
authors.initials: MB
authors.lastname: Neutzling
authors.forename: José Augusto A C
authors.initials: JA
authors.lastname: Taddei
authors.forename: Denise P
authors.initials: DP
authors.lastname: Gigante
mesh_terms: D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D000328:Adult; D015992:Body Mass Index; D001938:Brazil / Q000453:epidemiology; D001942:Breast Feeding / Q000706:statistics & numerical data; D016022:Case-Control Studies; D004038:Diet, Reducing; D015444:Exercise; D005192:Family Health; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D013334:Students / Q000523:psychology