The Healthy Start Project: Primary Prevention of Overweight in Preschool Children Susceptible to Future Overweight

Obesity prevention should remain a priority, although there is some evidence of a possible leveling off in some age groups across European countries and in USA, Japan and Australia. Besides adult health problems such as type-2 diabetes and cardiovascular diseases, obesity in childhood is associated with psychological and social problems, low self-esteem, stigmatization and being teased and bullied by friends. Danish research suggests that the causes behind the increase in obesity occurrence are present already in early childhood, and that prevention of obesity therefore has to start early. Research has suggested that at least three sub-groups can be considered susceptible to develop obesity: Children with obesity among their 1st degree relatives; children with a high birth weight or children coming from socially disadvantaged families (low socioeconomic status). Earlier intervention programs has showed little effect in preventing excessive weight gain and knowledge on how to develop effective intervention programs that reduce overweight and obesity remains limited. It has been suggested that future prevention programs may be more successful if specifically targeting groups that are at high risk, as mention above, of excessive weight gain.

Based on these suggestions, the "Sund Start" project was initiated. The purpose of the study was to determine whether aiming prevention towards 2-6 years old Danish children who were yet normal weight, but were considered susceptible to develop overweight or obese could prevent later on risk of becoming overweight or obese. Furthermore, to investigate if it was possible to improve diet habits, increase physical activity, reduce stress and improve sleeping habits among children at high risk for later on overweight and obesity.

The "Sund Start" project will contribute with knowledge about whether targeting normal weight, predisposed children is effective in preventing overweight and obesity, and if reduced stress and improved sleep, should be considered important new obesity prevention tools. Moreover, the project will contribute with knowledge about how to change lifestyle and its effects on development of overweight and obesity in high risk Danish preschool children.

In 2009, data on all births between 2004 and 2007 in 11 selected municipalities from the greater Copenhagen area was obtained from the Danish national birth register at the National Board of Health. This register contains information on all births, whether at hospital or home, on factors such as birth weight and length, height and pre-pregnant weight of the mother, parity, and Central Personal Registry number (CPR-number). Data on socioeconomic status was obtained from the administrative birth forms. This was done manually using the CPR-numbers obtained from the birth register.

After selection of the children eligible for participation, the children were allocated to three groups, (intervention group, control group, shadow group) using computer based randomization. All siblings were allocated to the same group. After the random allocation, children from the intervention group and the control group were sent a letter with an invitation to participate in the project. Children from the shadow group were also identified, and their general practitioners were contacted and asked for information on each child's height and weight.

Eligibility Criteria:
Inclusion Criteria:

* Born between 2004-2007
* Born in 11 selected municipalities in the greater Copenhagen area
* Classified as susceptible to overweight and obesity (At least one of the following risk factors present: A high birth weight (\> 4000 grams), maternal pre-pregnancy obesity (BMI \> 28 kg/m\^2), or maternal low education (\<= 10 years)
* Normal weight at baseline examination

Exclusion Criteria:

* Moved to another municipality after birth,
* Had requested protection from participation in statistical or scientific surveys based on data delivered from the Danish Central Person Registry
* No permanent address
* Lived in a children's home
* Had died
* Had emigrated
* Registered in the Danish Central Person Registry as being disappeared or had unknown life status
* Not speaking Danish
* Overweight (including obesity) at baseline examination