Reliability and Validity of the International Physical Activity Questionnaire (IPAQ) in Elderly Adults: The Fujiwara-kyo Study

Background: The International Physical Activity Questionnaire (IPAQ) is a self-reported questionnaire for assessing physical activity and has been tested in 12 countries among adults aged 18 to 65 years. The present study evaluated the reliability and validity of the IPAQ among adults aged 65 years and older. Methods: The study included 164 men and 161 women selected from participants of the Fujiwara-kyo Study, a prospective cohort of elderly Japanese adults. To examine test-retest reliability, the participants were asked to complete the IPAQ twice, 2 weeks apart. The criterion validity of the IPAQ was tested by using an accelerometer. Results: Based on intraclass correlation coefficients, the reliability of the total IPAQ was 0.65 and 0.57 for men and women, respectively, aged 65 to 74 years and 0.50 and 0.56 for those aged 75 to 89 years. The Spearman correlation coefficients between total IPAQ score and total physical activity measured by accelerometer (TPA-AC) were 0.42 and 0.49 for men and women, respectively, aged 65 to 74 and 0.53 and 0.49 for those aged 75 to 89. Weighted kappa coefficients between total IPAQ score and TPA-AC were 0.49 and 0.39 for men and women, respectively, aged 65 to 74 and 0.46 and 0.47 for those aged 75 to 89. Conclusions: The reliability of the IPAQ was not sufficient, but the validity was adequate. Although there were some limitations with regard to repeatability and agreement in classification, the IPAQ was a useful tool for assessing physical activity among elderly adults.