Impact of methodological approaches in the agreement between subjective and objective methods for assessing screen time and sedentary behavior in pediatric population: a systematic review

Introduction: sedentary behavior is an important target for health promotion. In this systematic review, we aimed to provide evidence to support decisions about measurement approach choices for subjectively assessing sedentary behavior in pediatric population, adopting objective methods as the reference. Methods: in this systematic review with meta-analysis, published studies were retrieved from electronic databases: Medline (PubMed), Web of Science, Embase, SPORTDiscus, BioMed Central and SCOPUS. We considered studies evaluating sedentary behavior agreement through questionnaire and/or diary in comparison with an objective measure. A total of six inclusion criteria v, rere used. We synthesized the data using correlation coefficients (r) as an indicator of agreement estimates. The review protocol is registered in the PROSPERO database (CRD42014015138). Results: a total of 14 studies met the inclusion criteria with ages ranging from 3 to 17.5 years and provided 17 agreement analyses. Thirteen of these agreement analyses (76.5%) reported correlation coefficients. We found two major groups of sedentary activities: screen time (47.1%) and sedentary behaviors (52.9%). The pooled agreement between questionnaires and accelerometers for assessing self-reported screen time was negative (r =-0.15; Cl 95%:-0.17 to-0.13). Conversely, when the sedentary behavior was assessed by questionnaires and accelerometers, the pooled agreement, vas positive for parent-reporting (r = 0.09; Cl 95%; 0.04 to 0.13) and self-reporting (r = 0.43; CI 95%: 0.40 to 0.47) in children and adolescents, respectively. Conclusion: questionnaires have positive agreement with accelerometers for assessing sedentary behavior, whereas the agreement is negative for assessing screen time. Self-reported questionnaires are recommended methods to measure sedentary behavior in adolescents

Prevalence of cardiovascular risk factors, the association with socioeconomic variables in adolescents from Low-Income region

Objectives: To estimate the prevalence of obesity, overweight, abdominal obesity and high blood pressure in a sample of adolescents from a low-income city in Brazil and to estimate the relationship with the socioeconomic status of the family, the education level of the family provider and the type of school. Methods: This cross-sectional study randomly sampled 1,014 adolescents (54.8% girls), between 14-19 years of age, attending high school from Imperatriz (MA). The outcomes of this study were: obesity and overweight, abdominal obesity and high blood pressure (systolic and/ or diastolic). The independent variables were: socioeconomic status (SES) of the family, education level of the family provider (ELFP) and type of school. The confounding variables were: gender, age and physical activity level. Prevalence was estimated, and the association between the endpoints and the independent variables was analyzed using a prevalence ratio (PR), with a 95% confidence interval, estimated by Poisson regression. Results: The overall prevalence of obesity was 3.8%, overweight, 13.1%, abdominal obesity, 22.7% and high blood pressure, 21.3%. The adjusted analysis indicated that girls with high SES showed an increased likelihood to be overweight (PR=1.71 [95% IC: 1.13-2.87]), while private school boys had an increased likelihood of obesity (PR=1.79 [95% CI: 1.04-3.08]) and abdominal obesity (PR =1.64 [95% CI: 1.06-2.54]). Conclusion: The prevalence of CVDR is high in adolescents from this low-income region. Boys from private schools are more likely to have obesity and abdominal obesity, and girls with high SES are more likely to be overweight

Reliability and validity of body weight and body image perception in children and adolescents from the South American Youth/Child Cardiovascular and Environmental (SAYCARE) Study

Objective: To assess the reliability and validity of body weight (BW) and body image (BI) perception reported by parents (in children) and by adolescents in a South American population. Design: Cross-sectional study. BW perception was evaluated by the question, "Do you think you/your child are/is: severely wasted, wasted, normal weight, overweight, obese?" BI perception was evaluated using the Gardner scale. To evaluate reliability, BW and BI perceptions were reported twice, two weeks apart. To evaluate validity, the BW and BI perceptions were compared with WHO BMI Z-scores. Kappa and Kendall's tau-c coefficients were obtained. Setting: Public and private schools and high schools from six countries of South America (Argentina, Peru, Colombia, Uruguay, Chile, Brazil). Participants: Children aged 3-10 years (n 635) and adolescents aged 11-17 years (n 400). Results: Reliability of BW perception was fair in children's parents (k=0·337) and substantial in adolescents (k=0·709). Validity of BW perception was slight in children's parents (k=0·176) and fair in adolescents (k=0·268). When evaluating BI, most children were perceived by parents as having lower weight. Reliability of BI perception was slight in children's parents (k=0·124) and moderate in adolescents (k=0·599). Validity of BI perception was poor in children's parents (k=-0·018) and slight in adolescents (k=0·023). Conclusions: Reliability of BW and BI perceptions was higher in adolescents than in children's parents. Validity of BW perception was good among the parents of the children and adolescents with underweight and normal weight