Predictors of Changes in Sleep Duration in Dutch Primary Schoolchildren: the ChecKid Study.

BACKGROUND: Healthy sleep duration is essential to health and well-being in childhood and later life. Unfortunately, recent evidence shows a decline in sleep duration among children. Although effective interventions promoting healthy sleep duration require insight into its predictors, data on these factors are scarce. This study therefore investigated (i) which individual (lifestyle), social and cultural factors, and living conditions and (ii) which changes in these factors might be associated with the changes in sleep duration of Dutch primary schoolchildren observed over time. METHOD: Data from the ChecKid study was used, a dynamic cohort study among 4-13-year-old children living in the city of Zwolle, the Netherlands. Associations between changes in sleep duration and individual (lifestyle) factors (i.e., age, sex, physical activity behavior, sugar-sweetened beverage consumption, screen behavior), social and cultural factors (i.e., parental rules, ethnicity), and living conditions (i.e., parental education, presence of screens in the bedroom, household size) were analyzed using multivariable linear regression. RESULTS: A total of 1180 children participated, aged 6.6 ± 1.4 years in 2009. Mean sleep duration decreased from 11.4 ± 0.5 h/night in 2009 to 11.0 ± 0.5 h/night in 2012. Older children, boys, children who used screens after dinner, children with greater computer/game console use, and children whose parents had low levels of education had a greater decrease in sleep duration. CONCLUSIONS: This article reports on one of the first large, longitudinal cohort studies on predictors of child sleep duration. The results of the study can inform future interventions aimed at promoting healthy sleep in primary schoolchildren.

Agreement between parent and child report of physical activity, sedentary and dietary behaviours in 9-12-year-old children and associations with children's weight status.

BACKGROUND: To date, population based surveys aimed at gaining insight in health related behaviour of children have often used either child self-reports or parent proxy reports. It remains unclear however, if surveys using different sources of information from either parents or children are comparable. In addition, (over)weight status of children can lead to under- and over reporting by parents and children as a result of social desirability bias. We aimed at gaining insight in the level of agreement between parents and child reports regarding aspects of certain dietary, physical activity and sedentary behaviours, and whether there are differences in agreement between parents and child reports in healthy-weight and overweight children. METHODS: Weighted kappa was used to determine the level of agreement between child and parent reports on health-related behaviour in 1998 parent-child dyads. We also stratified for weight status of the children. Information on children's health related behaviours was obtained by parental and children's questionnaires, and children's height and weight were measured. Associations between children's weight status and children reporting less, reporting more and reporting the same amount of health behaviour as their parents were investigated with multinomial logistic regression analysis. RESULTS: The Cohen's kappa coefficients ranged from almost perfect agreement for the variable means of transportation, fair for the variables breakfast consumption and frequency of outside play to slight for the variables duration of outside play, frequency and duration of TV/DVD viewing and family dinner. Overweight children were significantly more likely to report less breakfast consumption (OR = 2.6 (95% CI: 1.3 - 5.1)) and lower frequency of outside play than their parents (OR = 1.8 (95% CI: 1.1 - 2.9)). CONCLUSION: There can be considerable disagreement between the health related behaviours of children as reported by parents or the children themselves. Based on the present study, it cannot be concluded whether parents' or children's reports are more accurate. For future studies, social desirability and recall bias would be best demonstrated in a validation study comparing child and parent self-reports with more objective measures of physical activity and food intake.

Identifying developmental trajectories of body mass index in childhood using latent class growth (mixture) modelling: associations with dietary, sedentary and physical activity behaviors: a longitudinal study.

BACKGROUND: To date, many epidemiologic studies examining associations between obesity and dietary and sedentary/physical activity behaviors have focused on assessing Body Mass Index (BMI) at one point in time. Recent developments in statistical techniques make it possible to study the potential heterogeneity in the development of BMI during childhood by identifying distinct subpopulations characterized by distinct developmental trajectories. Using Latent Class Growth (Mixture) Modelling (LCGMM) techniques we aimed to identify BMI trajectories in childhood and to examine associations between these distinct trajectories and dietary, sedentary and physical activity behaviors. METHODS: This longitudinal study explored BMI standard deviation score (SDS) trajectories in a sample of 613 children from 4 to 12 years of age. In 2006, 2009 and 2012 information on children's health related behaviors was obtained by parental questionnaires, and children's height and weight were measured. Associations with behaviors were investigated with logistic regression models. RESULTS: We identified two BMI SDS trajectories; a decreasing BMI SDS trajectory (n = 416; 68 %) and an increasing BMI SDS trajectory (n = 197; 32 %). The increasing BMI SDS trajectory consisted of more participants of lower socio-economic status (SES) and of non-western ethnicity. Maternal overweight status was associated with being in the increasing BMI SDS trajectory at both baseline and follow-up six years later (2006: Odds Ratio (OR), 2.9; 95 % confidence interval (CI) 1.9 to 4.3; 2012 OR, 1.8; 95 % CI 1.2 to 2.6). The increasing BMI SDS trajectory was associated with the following behaviors; drinking sugared drinks > 3 glasses per day, participation in organized sports < 1 h per week, and TV viewing > 2 h per day, though participation in organized sports at follow-up was the only significant result. CONCLUSIONS: Our results indicate the importance of healthy lifestyle behaviors at a young age, and indicate that maternal BMI is a very important risk factor for the development of childhood overweight. Comprehension of heterogeneity in the development of BMI and associations with modifiable health related behaviors is interesting for prevention by targeting high risk behaviors in early childhood, especially in low SES children, children of non-western ethnicity and children whose mother is overweight.

Behavioural and socio-demographic characteristics of Dutch neighbourhoods with high prevalence of childhood obesity.

OBJECTIVE: To identify neighbourhoods with increased prevalence of overweight children and to examine whether the association between neighbourhood and overweight can be explained by demographic characteristics and energy-related behaviours. METHOD: This cross-sectional study was carried out among 4,072 primary schoolchildren in the city of Zwolle, The Netherlands. Data collection consisted of measured height, weight and waist circumference, and a parental questionnaire on socio-demographic characteristics, dietary and (in)activity behaviour of their child. With multivariate logistic regressions, associations between unhealthy behaviours and neighbourhoods (defined by postal code) with high and low prevalence of childhood overweight were investigated. RESULTS: In three neighbourhoods the prevalence of overweight was significantly higher (16.5% vs. 10.6%, p < 0.05). The odds of living in these neighbourhoods were higher among children watching >2 h television/day (OR: 1.57; 95% CI: 1.15-2.14), not eating breakfast daily (OR: 2.86; 95% CI: 1.93-4.23), drinking >3 glasses/day sugared drinks (OR: 1.23; 95% CI: 1.01-1.50) on weekdays and not participating in organized sports (OR: 1.32; 95% CI: 1.09-1.59). This odds was however lower among children eating <2 fruit/day (OR: 0.83; 95% CI: 0.69-1.00) on weekends. The association between neighbourhood and overweight altered slightly after adjustment for socio-demographic and behavioural characteristics during weekdays (OR: 1.42; 95% CI: 1.05-1.92) and weekends (OR: 1.50; 95% CI; 1.11-2.02). CONCLUSION: Three neighbourhoods with higher prevalence of overweight were identified. A small part of the association between overweight and neighbourhood is explained by socio-demographic factors and unhealthy behaviours measured in this study. Neighbourhoods with higher overweight prevalence are a priority setting for targeted interventions to prevent overweight. The association between neighbourhood and overweight needs to be explored further to understand the role the neighbourhood can play in tackling overweight.

The prevalence of overweight and obesity and its determinants in children with and without disabilities.

OBJECTIVES: To compare the prevalence of overweight and obesity and nutrition and physical activity behavior between primary school children with and without disabilities. STUDY DESIGN: Body weight and height were measured in 4072 children from regular primary schools in the city of Zwolle, the Netherlands, and in 85 children from a school for children with disabilities. Furthermore, parents completed a questionnaire on the child's nutrition and physical activity behavior. A χ(2) analysis was used to test categorical variables between groups, and analysis of variance was used for continuous variables. RESULTS: The prevalence of overweight and obesity among disabled children was 30.6% and 10.6%, respectively, which is three and six times higher than in nondisabled children (P < .001). Furthermore, our study shows statistically significant differences in nutrition and physical activity behavior between disabled and nondisabled children. CONCLUSIONS: There is a need to promote a healthy lifestyle and to reduce the prevalence of overweight and obesity in disabled children.