Association of screen time and physical activity with health-related quality of life in Iranian children and adolescents 11 Medical and Health Sciences 1117 Public Health and Health Services

Background: Health-related quality of life (HRQoL) is a multidimensional concept with significant effects and children and adolescence; while physical activity (PA) and screen time (ST) have been suggested as its probable predictors. Present study aims to investigate the association of PA, ST and their combination, with HRQoL in a nationally-representative sample of Iranian children and adolescents. Methods: As for the estimated sample size, 25,000 students aged 6-18 years were selected via multi-stage cluster sampling from 30 provinces of Iran. Sociodemographic data was obtained by using the questionnaire of the World Health Organization-Global school based student health survey (GSHS). Persian Pediatric Quality of Life inventory (PedsQL) and Physical Activity Questionnaire for the pediatric age group (PAQ-A) were applied for evaluating HRQoL and PA, respectively. PA scores 1-1.9 and 2-5 were respectively considered as low and high PA. The average duration of time spent on watching TV and leisure time computer use were considered as ST behaviors. ST of less than 2 h was considered low. Results: Out of 25,000 invited individuals, 23,043 students (mean age: 12.5) completed the study (response rate: 92.17). In linear regression models, ST duration had significant inverse association with total QoL (β:-0.49, p < 0.05). PA showed positive significant associations with HRQoL total score (β: 1.8, p < 0.05). Joint association of PA and ST revealed the strongest association of "high PA-low ST" category with total HRQoL (β: 2.2, p < 0.05); while "high PA-high ST" showed better total HRQoL score (β: 1.3) compared to "low PA-low ST" subgroup. Conclusion: Both PA and ST are significantly and independently associated with HRQoL in Iranian children and adolescents; while the adverse effect of prolonged ST could be diminished by a high PA. © 2019 The Author(s)

Association of neck circumference with general and abdominal obesity in children and adolescents: The weight disorders survey of the CASPIAN-IV study

Objectives: This study aimed to evaluate the association of neck circumference (NC) with obesity to determine the sex-specific and age-specific optimal cut-off points of this measure in association with obesity in a national sample of the Iranian paediatric population. Methods: This survey on weight disorders was conducted among a national sample of Iranian children and adolescents, aged 6-18 years. Using the area under the curve (AUC) of the receiver operator characteristic curves, we evaluated the association of NC with general and abdominal obesity. Results: This national survey was conducted among 23 043 school students (50.8 boys) with a mean age (SD) of 12.55 (3.31) years. A significant association was documented between NC and other anthropometric measures in both sexes and in the whole population. In all age groups and genders, NC performed relatively well in classifying participants to overweight (AUC: 0.67 to 0.75, p<0.001), general obesity (AUC: 0.81 to 0.85, p<0.001) and abdominal obesity (AUC: 0.73 to 0.78, p<0.001). Conclusions: NC can be considered as a simple timesaving clinical tool for obesity detection in large population-based studies in children and adolescents. It is significantly correlated with indices of adiposity and can reliably identify children with general and abdominal obesity in the Iranian paediatric population