Youth and Sport Study - a 20 Year Follow-up Study of Danish Teenagers Born Between 1964 and 1969

The first baseline study was conducted in 1983 and included 1260 students in high school or trade school. The questionnaire was designed with focus on various aspects of sports and physical activity beside more general questions on family, socioeconomic status, height, weight, alcohol intake, smoking, etc. Furthermore, the participants were subjected to a set of physical tests and measurements.

The second baseline study was conducted in 1985 and included a representative sample of 2498 teenagers drawn from the Danish Civil Registration (CPR) and invited to participate in the study with the aim of validating the results from the first baseline sample. The study consisted of a questionnaire with virtually the same questions as the questionnaire from 1983. A short 28-item food frequency questionnaire (FFQ) was added to the questionnaire, as well as a few questions about dietary habits.

The follow-up study was carried out in 2005, when the subjects had reached an age of around 40 years. A total of 1904 subjects were traced and asked to complete a general questionnaire, a food frequency questionnaire, and deliver a DNA sample, all distributed and returned through mail correspondence. The general questionnaire included questions on education, occupation, height, previous and present weight, weight loss history, physical activity, smoking, civil status, children, other family, stress, diseases, hospital admissions, and medicine use, among other things. The questions about physical activity were adopted from the baseline questionnaire. Other questions were adopted from other validated questionnaires. Moreover, a semi-quantitative, 195-item Food Frequency Questionnaire (FFQ), which previously has been used and validated in the Danish "Diet, Cancer and Health" study was included. The study was approved by the local ethics committee for Copenhagen and Frederiksberg (J.nr. KF 01-260/04).