Investigating social inequalities & determinants of weight development in youth: Applying longitudinal, environmental and experimental data

The researcher project "Investigating social inequalities & determinants of weight development in youth: Applying longitudinal, environmental and experimental data." used data from the Norwegian Longitudinal Health Behavior (NLHB) study, a European cross-sectional survey from the EU-project ENERGY and the Norwegian school-based intervention study "HEalth In Adoelscence (HEIA)". In the period from October 2013 to June 2015, 3 articles were published from the HEIA-project and 1 from the ENERGY-project. The HEIA-study was a randomized, controlled school-based intervention study to promote healthy weight development among 11-13 year olds through a healthy diet and physical activity. The study was conducted in 12 intervention schools and 25 control schools in South Eastern Norway in 2007-09. There were more intervention than control schools in order to follow the natural development of weight and weight-related behaviours in the control group in this crucial phase of life when children gain more freedom to decide about their own dietary habits, physical activity and screen time. The results in the last two effect articles showed no gender differences in effects on intake of fruit, vegetables or sugarsweetened beverages after 20 months, but the reduction in intake of lemonade was greater among children of parents with lower education. Furthermore, time in front of the TV on weekdays increased less among normal weight than among overweight children, and the child?s weight status was associated with parents? report of regulation of screen time. In a methodological article on factors associated with the 13-year olds ability to correctly self-report on weight and height, it was found that overweight girls and boys underreport on their body mass index (BMI) compared to normal weight children, but also that underweight girls overreported their BMI. Girls who reported to diet and boys who thought they weighed too much underreported their BMI, whereas how often they were weighing themselves or whether weight was important for how they looked upon themselves, were not associated with how well they self-reported their BMI. There were also no differences in the quality of the BMI data depending on the educational level of the parents. In the spring of 2010, a cross-sectional study of about 1000 10-12 year olds per country was conducted in 7 European countries as a part of the ENERGY-project. The children?s height and weight were measured according to a standardized protocol, the children filled in a questionnaire about diet and physical activity and factors that might influence these behaviours, and the principals filled in a questionnaire about the school environment. The association between school environment and intake of soft drinks with sugar was investigated. The results showed that discussing rules around food/drinks in school with teachers, parents, pupils and school nurses reduced the odds for drinking more than one glass of soft drinks per day. However, this association was no longer significant when adjusting for the parental educational level.

The prevalence of overweight and obesity among children and adolescents is increasing worldwide. Obesity is an important cause of chronic diseases like cancer, coronary heart disease and diabetes type 2. There are also clear socio-economic differences in overweight and these diseases. Treatment of obesity in childhood is difficult, but lifestyle interventions are promising. There is agreement that the obesity epidemic is driven by large environmental changes over the past few decades influencing the popul ations dietary behaviors and physical (in-)activity. However, there is a lack of longitudinal data to investigate social inequalities in weight development, few school-based intervention studies have assessed differences in effect by socio-economic status or gender and there is a lack of knowledge on how home and school environment might interact to shape energy balance related behaviors (EBRB) and weight development. The primary objective of this research is to investigate the development of socioeconomi c inequalities in weight development and EBRB from adolescence into adulthood, and to investigate the potential role of schools in preventing social inequalities in weight development and EBRB.The project will use data from two ongoing longitudinal studie s; one analytical on health behavior (ages 13-30) and one school-based intervention study on weight development (ages 11-13). The latter includes measurements of home and school environmental factors. Within an ongoing EU-funded project, a questionnaire t o assess obesogeneity of school environments will be added to a cross-sectional survey on weight and weight determinants of 11-12 year olds in 7 countries. The development of the questionnaire and the analyses will be guided by state of the art conceptual models and statistical analyses. This approach will bring the research field forward and help postulate new hypothesis on the relationship between weight development, social inequalities and environmental factors.