Predicting Changes in Physical Activity through Adolescence; The Young- HUNT Study, Norway

Physical inactivity is a risk factor for obesity and cardiovascular disease. Most adolescents tend to reduce their physical activity (PA) with increased age. For prevention strategies it is important to study predictors of change in physical activity during adolescence. PURPOSE: In a prospective design to study predictors of decreased PA from early to late adolescence with focus on gender differences. METHODS: The youth part of the Nord-Trøndelag Health Studies (HUNT), Norway, included 2348 students (46% boys) who participated both in Young-HUNT 1 (1995-1997, age 13-15 years) and at a follow-up Young-HUNT 2 (2000-2001, age 17-19 years). Identical questionnaires were used and standardized measurements of height and weight were performed in both studies. Data were analyzed by logistic regression. RESULTS: Out of the 2348 students, 692 (29.5%) were physically active (PA until sweating and/or breathing heavily) ≥4 days/week. At follow-up 386 (55.8%) of these had reduced their PA, and were physically active (PA until sweating and/or breathing heavily)