Reliability and validity of a sedentary behavior questionnaire for South American pediatric population: SAYCARE study.

BACKGROUND: Multicenter studies from Europe and the United States have developed specifically standardized questionnaires for assessing and comparing sedentary behavior, but they cannot be directly applied for South American countries. The aim of this study was to assess the reliability and validity of the South American Youth Cardiovascular and Environmental (SAYCARE) sedentary behavior questionnaire. METHODS: Children and adolescents from seven South American cities were involved in the test-retest reliability (children: n = 55; adolescents: n = 106) and concurrent validity (children: n = 93; adolescents: n = 94) studies. The SAYCARE sedentary behavior questionnaire was administered twice with two-week interval and the behaviors were parent-reported for children and self-reported for adolescents. Questions included time spent watching television, using a computer, playing console games, passive playing (only in children) and studying (only in adolescents) over the past week. Accelerometer was used for at least 3 days, including at least one weekend day. We compared values of sedentary time, using accelerometers, by quartiles of reported sedentary behavior time and their sum. RESULTS: The reliability of sedentary behavior time was moderate for children (rho ≥0.45 and k ≥ 0.40) and adolescents (rho ≥0.30). Comparisons between the questionnaire and accelerometer showed a low overall agreement, with the questionnaire systematically underreporting sedentary time in children (at least, - 332.6 ± 138.5 min/day) and adolescents (at least, - 399.7 ± 105.0 min/day). CONCLUSION: The SAYCARE sedentary behavior questionnaire has acceptable reliability in children and adolescents. However, the findings of current study indicate that SAYCARE questionnaire is not surrogate of total sedentary time.

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

OBJECTIVE: The objective of this article is to test the reliability and validity of the new and innovative physical activity (PA) questionnaire. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.