title: Trends and correlates of overweight and obesity among adolescents from 2002 to 2010: a three-cohort study based on a representative sample of Portuguese adolescents.
abstract: OBJECTIVE
  To report the prevalence and factors associated with overweight/obesity in a representative sample of Portuguese adolescents, from three different cohorts.
  
  
  METHODS
  Data on 8,610 adolescents aged 11-17, who participated in the 2002, 2006, and 2010 Health Behaviour in School-aged Children survey (HBSC/WHO) were analyzed. Body mass index (BMI) was calculated based on self-reported weight/height. Factors investigated as potential correlates of overweight/obesity were as follows: physical activity, screen time, life satisfaction, and perception of health.
  
  
  RESULTS
  The prevalence of overweight/obesity was around 20% for boys and 17% for girls between 2002 and 2010. Among boys, the prevalence of overweight/obesity was negatively associated with age in 2002 (odds ratio, OR = 0.89, P < 0.01), 2006 (OR = 0.92, P < 0.05), and 2010 (OR = 0.91, P < 0.05). Those who engaged in physical activity were less likely to be classified as overweight/obese in 2006 (OR = 0.89, P < 0.01) and 2010 (OR = 0.92, P < 0.05). Among girls, as age increased, the likelihood of being overweight/obese significantly decreased in all years. Results from 2002 (OR = 0.69, P < 0.001) and 2010 (OR = 0.88, P < 0.01) varied by almost 20%.
  
  
  CONCLUSIONS
  The prevalence of overweight/obesity is still high, but seems to have stabilized. Physical activity, for boys, and perception of health, for girls, are factors associated with a lower likelihood of being overweight or obese.
authors.affiliation: Projeto Aventura Social, Lisboa, Portugal; Centro Interdisciplinar de Estudo da Performance Humana, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Adilson
authors.initials: A
authors.lastname: Marques
authors.forename: Margarida
authors.initials: M
authors.lastname: Gaspar De Matos
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001294:Attitude to Health; D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D003201:Computers; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology; D010549:Personal Satisfaction; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D057185:Sedentary Behavior; D013690:Television; D013997:Time Factors