Sex differences in time trends for overweight and obesity in adolescents: The Young-HUNT study

Abstract

To investigate sex differences in the prevalence and extent of overweight and obesity in adolescents aged 14-18 years. 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. 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. 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.