title: Sex differences in time trends for overweight and obesity in adolescents: the Young-HUNT study.
abstract: OBJECTIVE
  To investigate sex differences in the prevalence and extent of overweight and obesity in adolescents aged 14-18 years.
  
  
  METHODS
  Standardized measurements of height and weight were collected from surveys of adolescents in the same geographical area in 1966-69 (n = 8378) and in 1995-97 (n = 6673). The prevalence rates of overweight and obesity were calculated using criteria approved by the International Obesity Task Force. The extents of overweight and obesity were assessed by computing age- and sex-specific body mass index (BMI) percentiles.
  
  
  RESULTS
  In 1995-97, 17.2% met the criteria for either overweight or obesity, as compared with 10.7% in 1966-69. The prevalence of overweight and obesity combined was higher in girls (13.0%) than in boys (8.5%) in 1966-69 (difference 4.5%, 95% confidence interval (CI) 3.1-5.9), while no sex difference was found in 1995-97 (girls 16.9%, boys 17.5%, difference -0.6, 95% CI -2.3-1.1). The increase in overweight was greater in boys (6.2PP, 95% CI 4.7-7.6) than in girls (1.9PP, 95% CI 0.4-3.5), while the sex difference in increased obesity was smaller (boys 2.8PP, 95% CI 2.1-3.4, girls 2.0PP, 95% CI 1.3-2.6). The increase in extent of overweight and obesity was highest in boys. The values of the 85th percentile and the 95th percentile in boys increased by 1.3 and 3.0 BMI units, respectively. The corresponding increases in girls were 0.7 and 1.7 BMI units.
  
  
  CONCLUSIONS
  A marked sex difference in time trends for both the prevalence and extent of overweight and obesity, with a more pronounced increase in boys than in girls, was demonstrated. This might have implications for preventive strategies.
authors.affiliation: HUNT Research Centre, Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Verdal, Norway. sigrid.bjornelv@ntnu.no
authors.forename: Sigrid
authors.initials: S
authors.lastname: Bjornelv
authors.forename: Stian
authors.initials: S
authors.lastname: Lydersen
authors.forename: Jostein
authors.initials: J
authors.lastname: Holmen
authors.forename: Tom Ivar
authors.initials: TI
authors.lastname: Lund Nilsen
authors.forename: Turid Lingaas
authors.initials: TL
authors.lastname: Holmen
mesh_terms: D000293:Adolescent; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D050177:Overweight / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D015995:Prevalence; D012737:Sex Factors; D013997:Time Factors