Reliability and Validity of a Questionnaire for Physical Activity Assessment in South American Children and Adolescents: The SAYCARE Study.

Abstract

The objective of this article is to test the reliability and validity of the new and innovative physical activity (PA) questionnaire. Subsamples from the South American Youth/Child Cardiovascular and Environment Study (SAYCARE) study were included to examine its reliability (children: n = 161; adolescents: n = 177) and validity (children: n = 82; adolescents: n = 60). The questionnaire consists of three dimensions of PA (leisure, active commuting, and school) performed during the last week. To assess its validity, the subjects wore accelerometers for at least 3 days and 8 h/d (at least one weekend day). The reliability was analyzed by correlation coefficients. In addition, Bland-Altman analysis and a multilevel regression were applied to estimate the measurement bias, limits of agreement, and influence of contextual variables. In children, the questionnaire showed consistent reliability (ρ = 0.56) and moderate validity (ρ = 0.46), and the contextual variable variance explained 43.0% with -22.9 min/d bias. In adolescents, the reliability was higher (ρ = 0.76) and the validity was almost excellent (ρ = 0.88), with 66.7% of the variance explained by city level with 16.0 min/d PA bias. The SAYCARE PA questionnaire shows acceptable (in children) to strong (in adolescents) reliability and strong validity in the measurement of PA in the pediatric population from low- to middle-income countries.