Ice skating on Spaarne, near Haarlem

For the fourth year in a row, we have a few weeks of good frost, and the ice is nice and thick on many canals and lakes. Is skipped work for a few hours today to enjoy the ice and went for a nice ride on my skates on the Spaarne canal, near Haarlem.
See http://youtu.be/9-JZgCUlxKo for a video impression....

The importance of parental involvement in school-based programs to promote healthy nutrition and physical activity

Parental involvement is often advocated as important for school-based interventions, because parents are a main determinant of children's dietary and physical activity behaviors. We conducted a systematic review of the available scientific literature on this issue to explore the available scientific evidence for this claim. This review thus aimed at determining the impact of parental involvement in school-based obesity prevention interventions in children and adolescents. Our review was conducted as part of the ENERGY project, a European Commission-funded project to improve obesity prevention among school-aged children across Europe. The review was just published in the International Journal of Public Health. Wendy van Lippevelde, a PhD candidate from the University of Ghent was first author.
Akltough some positive effects of parental involvement were found on children's behaviours and behavioural determinants, the evidence was inconclusive. Maybe the most prominebt outcome of our review was that so few studies have been conducted that have explicetely tested the effect of parental involvement, and celarly more studies are needed to address this important issue.  There is a need for more studies comparing school-based interventions with and without a parental component, and dose, strategies and content of parental components of school-based interventions should be better reported in research articles.

Genetic and environmental Influences on screen-time behaviors among adolescents

In a paper with Dr.Niels van der Aa as first author, just published online by Arcives of Pediatric and Adolescent Medicine, we report on an investigation of the genetic and environmental influences on sedentary behavior, i.e. TV and computer time, among adolescents. The paper is based on analyes of cross sectional data from the Netherlands Twin Registrer. The Netherlands Twin Register (NTR) was established in 1987 at the Vrije Universiteit in Amsterdam for scientific research purposes. The study of twins and their family members can provide insight into what extent the causes of differences between individuals are determined by genetic and environmental influences. Prof. Dorret Boomsma, (or see her EMGO personal page) co-author of the paper, is the founder of this registry.

The study published in Archives shows that differences in sedentary behavior can to a large extend be explained by genetic factors, and that the importance of genetic influence increases from age 12 to age 20. To be a bit more specific, our data showed that variation in adolescent sedentary behavior was largely accounted for by genetic and nonshared environmental factors, whereas shared environmental factors account for a substantial part of the variation among younger adolescents. The shift from shared environmental factors in the etiology of sedentary behavior among younger adolescents to genetic and nonshared environmental factors among older adolescents has consequences for intervention programs that aim to reduce adolescents' screen-tme behaviors. These require specific tailoring to age groups and need to focus on peers and parents in early adolescence but on the youngsters themselves at later ages.