title: Aggregation of the four main risk factors to non-communicable diseases among adolescents.
abstract: OBJECTIVE
  It was to investigate the cluster of four main risk behaviors (smoking, alcohol, physical inactivity and low consumption of fruits and vegetables) related to chronic diseases from Northeastern Brazil.
  
  
  METHODS
  Cross-sectional study with a representative sample (n = 600) of high school students from public schools in Caruaru, Pernambuco, Brazil. The cluster was evaluated by comparing the observed prevalence expected in all the possibilities of coupling between the behaviors. The logistic regression analysis was performed by grouping three or four behaviors, after adjusting for independent variables.
  
  
  RESULTS
  With the exception of smoking, other risk behaviors had prevalence rates above 20%. Only 0.3% (95%CI 0.1 - 1.3) of the students presented the four risk behaviors simultaneously, while 15.3% (95%CI 12.3 - 18.2) did not present anyone. Risk behaviors tended to cluster, particularly smoking and alcohol consumption, being more pronounced among boys, and physical inactivity and low consumption of fruits and vegetables among girls (p < 0.05). Regression analysis indicated that, among the independent variables, those students who do not have physical education classes were 2.1 times more likely to have three or more risk behaviors added.
  
  
  CONCLUSIONS
  The results of this study allow us to establish the prevalence of risk behaviors in cluster, which may have important implications for health policies and practices. It is suggested that educational and health actions are tested in schools, and physical education classes can be an important context for intervention.
authors.affiliation: Department of Physical Education, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: Rafael Miranda
authors.initials: RM
authors.lastname: Tassitano
authors.affiliation: Department of Population and Health, Universidade Federal do Rio Grande, Rio Grande, RS, Brazil.
authors.forename: Samuel Carvalho
authors.initials: SC
authors.lastname: Dumith
authors.affiliation: Department of Nutrition, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
authors.forename: David Alejandro González
authors.initials: DA
authors.lastname: Chica
authors.affiliation: Department of Physical Education, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: Maria Cecília Marinho
authors.initials: MC
authors.lastname: Tenório
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000009:adverse effects*; D001938:Brazil; D002908:Chronic Disease / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005638:Fruit; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012309:Risk-Taking; D057185:Sedentary Behavior; D012907:Smoking / Q000009:adverse effects*; D014675:Vegetables; D055815:Young Adult