Implementation evaluation of school-based obesity prevention programmes in youth; how, what and why?

In an ideal world, one combats public health problems with theory- and evidence-based programmes. In the real world, evidence-based programmes are often lacking and programmes that are developed and implemented are mainly practice-based. Furthermore, if evidence-based programs are available, these are often not implemented as intended, making the effectiveness in real life settings often much lower than ideal.
Three important generic implementation research questions in the context of programme evaluation are: (i) how to promote implementation as intended; (ii) what happens during implementation; and (iii) why did my programme (not) work? In an invited commentary just published in the journal Public Health Nutrition we -with soon-to-be Dr. Femke van Nassau as first author- discuss
these three questions, enriched by our experiences with the school-based obesity prevention programme DOiT(Dutch Obesity Intervention in Teenagers).

Parental modelling mediates parental education differences in children's TV time

Children from lower educated parents tend to have less positive health behaviours than kids from higher educated parents. Children's sport participation is a health behaviour, associated with positive health outcomes, while children's TV time -a sedentary behaviour- is associated with higher likelihood for overweight and obesity and lower cardiometabolic health. In a paper just published online in Preventive Medicine, we assessed whether differences in children's sport participation and TV time according to parental education were mediated by parental modelling, i.e. by 'example behaviour' of the parents. In other words: we wanted to explore if lower educated parents are less likely to participate in sports and watch more TV themselves and if these behaviours help explain the less positive health behaviours in their children. We used the data of the cross European ENERGY study. We found evidence that parental modelling was important for differences in children's health behaviours according to the level of education of their parents, especially regarding children's TV time.

DEDIPAC: Determinants of diet and physical activity Knowledge Hub

To address major societal challenges and enhance cooperation in research across Europe, the European Commission has initiated and facilitated ‘joint programming’. Joint programming is a process by which Member States engage in defining, developing and implementing a common strategic research agenda, based on a shared vision of how to address major societal challenges that no Member State is capable of resolving independently. Setting up a Joint Programming Initiative (JPI) should also contribute to avoiding unnecessary overlap and repetition of research, and enable and enhance the development and use of standardised research methods, procedures and data management. The Determinants of Diet and Physical Activity (DEDIPAC) Knowledge Hub (KH) is the first joint action of the European JPI ‘A Healthy Diet for a Healthy Life’. A paper describing the rationale, organisation and potential added value of DEDIPAC was just published in the International Journal of Behavioral Nutrition and Physical Activity. The objective of DEDIPAC is to contribute to improving understanding of the determinants of dietary, physical activity and sedentary behaviours. DEDIPAC KH is a multi-disciplinary consortium of 46 consortia and organisations supported by joint programming grants from 12 countries across Europe. The work is divided into three thematic areas: (I) assessment and harmonisation of methods for future research, surveillance and monitoring, and for evaluation of interventions and policies; (II) determinants of dietary, physical activity and sedentary behaviours across the life course and in vulnerable groups; and (III) evaluation and benchmarking of public health and policy interventions aimed at improving dietary, physical activity and sedentary behaviours. In the first three years, DEDIPAC KH will organise, develop, share and harmonise expertise, methods, measures, data and other infrastructure. This should further European research and improve the broad multi-disciplinary approach needed to study the interactions between multilevel determinants in influencing dietary, physical activity and sedentary behaviours. Insights will be translated into more effective interventions and policies for the promotion of healthier behaviours and more effective monitoring and evaluation of the impacts of such interventions.

An intervention aimed at interrupting sitting time in schoolchildren

Sedentary behaviour, especially prolonged uninterrupted sitting, may be bad for cardiometabolic health. Breaking up sitting time may be more effective for health promotion than reducing total sitting time. However, there are currently no studies available reporting intervention effects on breaking up children's sedentary time. In a study just published online in the journal Pediatric Exercise Science we report on a study in which we examined intervention effect on objectively measured number of breaks in sedentary time, number of sedentary bouts (≥10 mins) and total and average amount of time spent in those sedentary bouts among 10- to 12- year-old Belgian children. The total sample included 354 children aged 10-11 with valid ActiGraph accelerometer data at pre- and post-test. Only few and small intervention effects were found, namely on total time spent in sedentary bouts immediately after school hours and on average time spent in sedentary bouts before school hours  and immediately after school hours in favour of children from intervention schools. Unexpectedly, girls from intervention schools decreased the number of breaks during school hours
and increased the number of sedentary bouts on a weekend day, whereas girls in control schools showed an increase in number of breaks and a decrease in number of bouts. In conclusion, UP4FUN did not have a consistent or substantial effect on breaking up children's sedentary time and these data suggest that more intensive and longer lasting interventions are needed, if interrupting sitting time is to be further pursued.

Sedentary behaviour and health in children: Evaluating the evidence

There is much to do about sedentary behaviour -too much (prolonged) sitting, for example by means of TV watching, computer and other IT activities, long school or office days et cetera- as a possible risk factor for cardiometabolic health. Scientists have claimed that sedentary time is a risk factor for cardiometabolic health partly or largely independent of physical activity. I.e. even if you do enough exercise, if you sit most of the rest of the day, your cardiometablic health may be at unnecessary risk. Some countries have already proposed recommendations for maximum sedentary time and interventions to reduce or interrupt sedentary time have been developed and are being tested or implemented.
In a commentary just published in the journal Preventive Medicine, with Prof. Mai Chin A Paw as first author, we argue that the evidence for sedentary behaviour as an independent cardiometabolic risk factor for children and adolescents is certainly not yet convincing, and propose research that should be conducted first to see if a stronger case can be build for treating sedentary behaviour as a separate risk factor, before we start using the meagre means for preventative interventions on sedentary behaviour instead of promoting physical activity and healthy eating.

Personal, home- and friend-related factors regarding diet, physical activity and sedentary behaviours among schoolchildren in Europe

To design interventions that target energy balance-related behaviours -i.e. diet, physical activities (PA) and sedentary behaviours- among school-age children, knowledge the possible determinants of these behaviours is needed. In a study just published in PLOS ONE -with Dr. Saskia te Velde as first author- we investigated schoolchildren's  personal beliefs and attitudes, home- and friend-related variables regarding soft drink intake, fruit juice intake, breakfast consumption, TV viewing and physical activity in eight countries across Europe. This study was part of the ENERGY project.
A majority of the children reported unfavourable attitudes, preferences and subjective norms regarding soft drink, fruit juice intake and TV viewing accompanied with high availability and accessibility at home. Few children reported unfavourable attitudes and preferences regarding breakfast consumption and PA. Many children reported unfavourable health beliefs regarding breakfast consumption and TV viewing. Substantial differences between countries were observed, especially for variables regarding soft drink intake, breakfast consumption and TV viewing.
We concluded that children across Europe have favourable attitudes to some healthy behaviours (PA, breakfast intake) as well as to some unhealthy behaviours (soft drink consumption, TV viewing). Additionally, many children across Europe have personal beliefs and are exposed to social environments that are not supportive to engagement in healthy behaviours. Moreover, the large differences in personal, family and friend-related variables across Europe argue for implementing different intervention strategies in the different European countries.

Patterns in sedentary behaviour: data reduction issues

Sedentary behaviour may be another risk factor for obesity and cardiometabolic risk. Sedentary lipoprotein lipase activity, leading to a prolonged time in which cellular metabolism substrates are present in the vascular compartments.
behaviour is not the same as the opposite of lack of physical exercise: even people who have enough exercise may sit too much during the rest of the day. Recent evidence suggest that it may be prolonged, uninterrupted sitting -rather than total sitting time- that may increase cardiometabolic risk. Prolonged sitting leads to the loss of contractile stimulation in weight-bearing muscles, which suppresses skeletal muscle
However, measuring sitting time and sedentary patterns is not as straightforward as it may seem. Sedentary behaviour is maybe best measured with accelerometers, however, no consensus is yet established on such accelerometer data most validly reflect sedentary time or sedentary patterns.
In a study just published in PLOS ONE -with Prof. Mai Chin A Paw as first author- we aimed to establish evidence-based accelerometer data reduction criteria to accurately assess total sedentary time and sedentary patterns in children. More than 1000 children in five countries in Europe wore accelerometersfor at least 6 consecutive days. We explored 1) non-wear time criteria; 2) minimum daily valid wear time; 3) differences between weekday and weekend day; and 4) minimum number of days of accelerometer wear by comparing the effects of commonly used data reduction decisions on total sedentary time, and duration and number of prolonged sedentary bouts.
More than 60 consecutive minutes of zero counts was the optimal criterion for non-wear time. Increasing the definition of a valid day from 8 to 10 hours wear time hardly influenced the sedentary outcomes, while the sample size of children with more than 4 valid days increased from 69 to 81%. On weekdays, children had on average 1 hour more wear time, 50 minutes more total sedentary time, 26 minutes more sedentary time accumulated in bouts, and 1 more sedentary bout. At least 6 days of accelerometer data were needed to accurately represent weekly sedentary time and patterns.