Evaluation of a school-based multi-component programme to prevent overweight in primary school children

A considerable increase in the prevalence of overweight and obesity has been
observed among children in the Netherlands. An important period in the
development of overweight and obesity is the pre-adolescent period. A multitude
of interventions to prevent overweight in children exist, however evidence of
effectiveness is often missing. An evaluation study is proposed to test the
effectiveness, costs, and feasibility of a multi-component strategy that
includes a combination of educational and ecological activities directed at
physical activity, nutrition behaviour and causes of inactivity in primary
school children, 9-11 years old. In this project we will compose a
multi-component strategy to prevent overweight from best practices materials
drawn from existing Dutch prevention programmes. The American evidence based
programme Planet Health will provide the framework to give this multi-component
strategy a sound theoretical foundation. An evaluation study will be conducted
on the multi-component overweight prevention strategy to test the feasibility
and effectiveness of the programme and assess programme costs in the Dutch
setting.

The objectives of the project are to evaluate the effectiveness of the
school-based multi-component programme aimed at the promotion of healthy
nutrition behaviours, a reduction of inactivity, i.e. of television watching
and computer use, and the promotion of physical activity to prevent overweight
in primary school children 9-11 years old, and finally to assess the process
whereby the programme is implemented.

Effect evaluation
Schools will be assigned randomly to an intervention group or a control group.
The intervention schools will successively implement the multi-component
programme in groups 6 and 7 the year after. Control schools will have their
"usual care". They will continue lessons on nutrition or physical activity as
they use to give in their schoolclasses, but which are not combined in a
theoretically grounded multi-component programme as provided to the
intervention group. The control schools will be offered the opportunity to
implement the multi-component programme for free after the experiment is
finished. The school programmes of the control group (usual care) will be
closely monitored in the process evaluation (see below).
Outcome criteria will be measured 4 times: T0 and T1 at respectively the
beginning and end of the school year in group 6 of primary school; and T2 at
the end of the school year in group 7; and finally T3 halfway the school year
in group 8. Questionnaires will be administered in two ways at all measurement
time points. Part of the outcome variables are included in a structured
interview questionnaire, to be conducted during the physical assessments of BMI
and waist circumference. Other outcome variables are included in the written
questionnaires that will be completed by the pupils in class under the guidance
of teachers to achieve a maximum response rate.

Process evaluation
A process evaluation will be conducted to test whether the teachers of the
study groups are presenting the programme as intended using questionnairs,
registrations and observations. Moreover the childrens* and teachers'
assessment of the attractiveness and usability of the multi-component programme
will be established.

The following components will be included in the overweight prevention
programme for primary school children:
a. promotion of healthy nutrition behaviours: promotion of fruit and vegetable
intake, reduction of consumption of high fat and energy snacks and soft drinks,
promotion of healthy breakfast
b. reduction of inactivity i.e. of television watching, computer browsing and
the use of computer games
c. promotion of physical activity: promotion of school physical activities and
participation in sports outside school hours.
The multi-component strategy will be built on promising existing Dutch
school-based interventions that have been proven partially effective in a
single delivery design or that are potentially effective but have not yet been
evaluated. Some examples of existing potential projects in The Netherlands are
interventions on nutrition education developed by the Netherlands Nutrition
Centre (Voedingscentrum): *Smaaklessen* and *SchoolGruiten*. An intervention
aimed at ecological change is the National Schoolbreakfast project. Examples of
projects aiming at physical activity are *Kies voor hart en sport* developed by
the Dutch Heart foundation, and *Lekker fit*, developed by the GGD Rotterdam
Rijnmond. Where no usable interventions are available in the Dutch setting, we
will select components from Planet Health or Eat Well and Keep Moving or other
promising interventions.The intervention mapping (IM) protocol and the Dutch
Healthy School Model will be used to give the the multi-component programme a
sound foundation .
Change of the parents* parenting and health behaviours is not the primary aim
of this programme. Of course we will adopt parent aimed school activities when
the existing Dutch school-based interventions to be included in the programme
use principles of parent involvement.
School teachers will give the nutrition education and physical activity lessons
in their school classes. They will be trained to deliver the lessons as
intended.

The child will participate in the evaluation study during three school years. A
questionnaire will be filled out at four time points, taking half an hour per
time point. Research assistants of the community health services will weigh the
child and measure length and waist circumference. A 24-recall interview wil be
used to measure diet and physical activity behaviours. The physical measurments
and interview will take 20 minutes per child per time point. All mearuments
will take place at the child's school.
No specific risks are associated with participation in the evaluation study.