Criterion-related validity of the last 7-day, short form of the International Physical Activity Questionnaire in Swedish adults

Abstract

Objective: To examine the validity of the short, last 7-day, self-administered form of the International Physical Activity Questionnaire (IPAQ). Design: All subjects wore an accelerometer for seven consecutive days and completed the IPAQ questionnaire on the eighth day. Criterion validity was assessed by linear regression analysis and by modified Bland–Altman analysis. Specificity and sensitivity were calculated for classifying respondents according to the physical activity guidelines of the American College of Sports Medicine/Centers for Disease Control and Prevention. Setting: Workplaces in Uppsala, Sweden. Subjects: One hundred and eighty-five (87 males) participants, aged 20 to 69 years. Results: Total self-reported physical activity (PA) (MET-min day−1) was significantly correlated with average intensity of activity (counts min−1) from accelerometry (r=0.34, P<0.001). Gender, age, education and body mass index did not affect this relationship. Further, subcomponents of self-reported PA (time spent sitting, time in PA, time in moderate and vigorous activity (MVPA)) were significantly correlated with objectively measured PA (P<0.05). Self-reported time in PA was significantly different from time measured by accelerometry (mean difference: −25.9 min day−1; 95% limits of agreement: −172 to 120 min day−1; P<0.001). IPAQ identified 77% (specificity) of those who met the current PA guidelines of accumulating more than 30 min day−1 in MVPA as determined by accelerometry, whereas only 45% (sensitivity) of those not meeting the guidelines were classified correctly. Conclusions: Our results indicate that the short, last 7-days version of the IPAQ has acceptable criterion validity for use in Swedish adults. However, the IPAQ instrument significantly overestimated self-reported time spent in PA. The specificity to correctly classify people achieving current PA guidelines was acceptable, whereas the sensitivity was low.