Assessment of Physical Activity in a Group of Adults in Italy: Comparison of Two Different Methodologies

Abstract

Introduction: Physical activity levels are often monitored to assess health behaviours and their associations with health status, including mortality and morbidity rates in the population. The International Physical Activity Questionnaire (IPAQ-L) was developed in the late 1990s to obtain internationally comparable data on health related physical activity and several studies have shown its acceptable validity and reliability for population-based studies. The aim of this study was the comparison of the International Physical Activity Questionnaire (IPAQ-L) against an objective method such as accelerometry. Methods: 220 volunteers (105 men and 115 women), aged 18-65 years, were recruited. All volunteers wore an accelerometer for 7 consecutive days, after that, we required them to complete the IPAQ-L together with a lifestyle questionnaire containing questions on physical exercise, smoking habits, alcohol consumption and other demographic data (age, sex, ect). Moreover, we collected measure of weight (kg) and height (cm) according to the standard procedure; body mass index (kg body weight/m 2 body height) has been calculated. Results: IPAQ-L showed a significant tendency to overestimate time spent in vigorous and moderate activities (p=0.0000) and to underestimate time spent sitting (p=0.0000). Additionally, the differences in minutes per day of moderate and vigorous physical activities between the IPAQ-L and the accelerometer reported in questionnaire increased. Nevertheless, we found a low positive correlation (r =0.30; p<0.05) between total physical activity measured by accelerometer and that obtained by the IPAQ-L. Conclusions: Our results showed low to moderate correlations between IPAQ-L and accelerometer pointing out differences across physical activity categories. This is an aspect that should be taken into account prior to deciding on use of an instrument for the assessment of physical activity; especially in small population groups preference should come down to objective tools such as the accelerometer.