Physical activity questionnaire for adolescents validated against doubly labelled water

OBJECTIVE: To validate a physical activity questionnaire for adolescents (PAQA) adapted from the International Physical Activity Questionnaire (IPAQ). DESIGN: Energy expenditure was measured during a 14-day period with doubly labelled water (DLW). PAQA was administered as an interview at the end of the period, asking for physical activity in school, during transportation and leisure-time, during a habitual week. Energy expenditure (EE(PAQA)) was calculated as the product of total physical activity + sleep and predicted resting metabolic rate, and was compared to energy expenditure from DLW (EE(DLW)), thermic effect of feeding excluded. SETTING: Participants were recruited from grade 9 in a compulsory school in G?teborg, Sweden. All data were collected at school, and distribution of DLW and measuring of resting metabolic rate were performed at Sahlgrenska University Hospital. SUBJECTS: A total of 33 adolescents (16 girls, 17 boys) 15.7 (0.4) y performed all measurements. RESULTS:: For the whole group, PAQA underestimated energy expenditure by 3.8 (1.7) MJ (P<0.001). There was a strong correlation (r = 0.62, P<0.001) between EE(PAQA) and EE(DLW), but not for boys (r = 0.42, P = 0.090) and girls (r = 0.33, P = 0.22) separately. CONCLUSIONS: PAQA is not able to predict energy expenditure in Swedish adolescents, largely explained by the amount of unreported time. The ability to rank adolescents energy expenditure is questioned because of the gender effect, although we found a strong correlation for the whole group.