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ChecKid Study

Objectives

Overweight is considered as one of the largest public health problems. This is worrisome because especially obesity in children is associated with increased cardiovascular risk, diabetes mellitus type 2 and psychosocial problems. In addition overweight in childhood predicts overweight in adulthood. Moreover, adults who were obese children have an increased risk on morbidity and mortality independent of their adult weight. Therefore early prevention starting at a young age is very important. Also there is an urgent need for evidence based obesity prevention.

In recent years it has become evident that effective management of overweight and obesity should be a part of local integral health policy (Friedrich, 2007). The Zwolle city council wants work in an integral and durable way on the prevention of overweight in 0-19 year-olds.  Allready in 2005, during the implementation of the Big City policy (Grootstedenbeleid), the executive board decided that health care policy is a shared responsibility. This decision has been implemented in local policy to enhance a healthy living standard and environment, within broader aspirations of the city such as social cohesion, quality of life, differentiation and spatial quality.

This integral approach is based on five pillars: a sound political basis, the installation of a local projectmanager, cooperation between the public and private sector, social marketing and research concerning effectiveness. For purpose of this last goal and to monitor trends in life style and overweight, but also to identify high-risk groups, and to offer tailor-made prevention plans from different settings, the ChecKid study has been set up.

The objective is to study the trends and monitoring the prevalence of overweight and obesity among children in the age of 4 - 12 years in the city of Zwolle, the Netherlands. In addition ChecKid will contribute to monitor the effectiveness of a durable integral approach aimed at the neighbourhood that is momentarily in development in a few neighbourhoods in Zwolle.

Moreover, socio-demographic, lifestyle and environmental factors associated with overweight and obesity will be studied. The resulting data can directly be related to BMI and waist circumference because weight, height and waist circumference are measured in all children. The clustering of (un)healthy behaviours and the relationship between individual behaviour, the physical and social environment will be explored to implement interventions efficiently. 

The ChecKid study has a longitudinal design, in which primary school children will be followed, with measurements every three years. In 2006 the first wave of data collection has been completed during which nearly all the primary schools in Zwolle participated. The second wave is planned for autumn 2009. 

Collaborations

Partners in this project are the Zwolle city council, the local health services , the research centre prevention overweight Zwolle and several welfare organisations in the city.

Results

All primary schools in the city were asked to participate in the ChecKid study. If a school agreed to be included in the study, all children attending the school (4-12 years) were invited to participate by means of letters distributed via the schools to the parents. Data collection consisted of measuring length, weight and waist circumference of the children. In addition parents were asked to fill out a questionnaire on the child’s nutrition, physical (in) activity behaviour, and environmental determinants, as well as socio-demographic characteristics. The children of the highest three levels at primary school (group 6, 7, 8) filled out an extra questionnaire on health behaviour. Special education schools were not approached to participate in the ChecKid study; children were excluded if they received any form of special education. For these children a different cohort study was set up, namely the ChecKid + study.
Eighty percent of schools, n=41, participated in the baseline measurements, for both the anthropometrical measurements and questionnaires. Another 4 schools, 8%, only participated in the questionnaires for logistic reasons. Five schools, 12%, refused to participate, mostly because of other priorities. Participating schools were equally spread over the city of Zwolle. Within the schools that participated, the parent(s) of sixty-five percent of children (n=5,219) have given written informed consent. The ChecKid study is approved by the Medical Committee of the VU Medical Centre.
Body height, weight and waist circumference were measured using a protocol in 5,035 children (4% of children with informed consent was not measured, mostly because of illness) by trained students. The children’s BMI cut-off points suggested by Cole et al. (2000) were used to define underweight, healthy weight, overweight and obesity.
The questionnaire for parents included socio-demographic factors such as the child’s age, gender, postal code, ethnicity, and education level of the parents. In addition questions on health behaviour of the child and the parents’ opinion on the neighbourhood were included. A total of 4,257 questionnaires (81%) was filled out and returned by the parent(s), while another 356 questionnaires were added from the four schools that did not participate in the anthropometric measurements, resulting in a total of 4,613 questionnaires. For 4,072 children (78% of children with informed consent) both anthropometrical and parental questionnaire data were available.
Characteristics of the study population (N=4,072)
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Age in years, mean (SD)
n=4,072
8.1(2.3)
Gender
n=4,072
% boys
49.2
% girls
50.8
Socio-economic status
n=3,859
Low (%)
8.7
Medium (%)
34.5
High (%)
56.9
Ethnicity
n=4,040
Dutch (%)
87.3
Mixed Dutch and foreign (%)
7.3
Foreign (%)
5.4
Weight status
n=4,072
Underweight (%)
8.2
Healthy weight (%)
80.1
Overweight (%)
9.9
Obesity (%)
1.8
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The ChecKid study is still in an early phase. Many baseline analyses are currently ongoing. ChecKid is performed by the the Research Centre Prevention Overweight Zwolle (OPOZ) in close collaboration with local municipal health services. This research centre is a joint initiative of Hogeschool Windesheim, the VU University, and the EMGO +-institute of the VU medical centre The results will be used to develop and evaluate an integral durable approach to promote a healthy life style and to manage overweight in children living in Zwolle. This will be realized in close cooperation with the local government and municipal health care organisation (de GGD Ijsselland), ICARE child health care organisation (Thuiszorg ICARE) Academische Thuiszorgwerkplaats), Sportservice Zwolle, Isala Klinieken, MCC KLIK (cooperation between different health care providers), the lectureship The Healthy City (De Gezonde Stad) of Hogeschool Windesheim.
At this moment, the preparations for the second wave of data collection are ongoing. This will provide us with the first longitudinal data that will provide information on the course of overweight and obesity and the effectiveness of community based interventions.
REFERENCES

Schokker, D.F, de Jong E, Visscher, T.L.S, Seidell, J.C., Bleeker, S.A. , Renders, C.M. The role of the neighbourhood in the prevalence of obesity, nutrition and physical activity behaviour in children in a Dutch city: targeting a community intervention. Submitted

Contact information

Dr C.M. Renders, cm.renders@vumc.nl 020-4441706
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