English summary: Prevalence of overweight children and difficulties in defining obesity

Background

The prevalence of overweight and obesity in children is increasing rapidly both worldwide and in Finland. The main aim of the study was to assess the prevalence of overweight children in Finland comparing children in Kainuu, Northern Finland and in Turku, Southern Finland. The aim was also to study whether different methods of defining overweight and obesity have an impact on the classification of overweight or obese children.

Methods

This study was conducted by the Child Health Monitoring Development project (LATE) in 2007-2009. The data were collected from health checkups in child health care and school health care units in ten different health centres and in Kainuu and Turku. The target groups were children six months, one, three and five years of age and pupils in first, fifth and eighth grades. The height and weight of these children were measured by public health nurses trained in data collection. Overweight was defined using the Finnish growth curves criteria of weight-for-height (%) and the international (International Obesity Task Force IOTF) BMI cut-off values. The prevalence of overweight was assessed separately for boys and girls and for each age group.

Results

The results showed that the prevalence of overweight children in the age group 3-12 years 17-19% defined by international BMI criteria and 16% by the weight-for-height criteria. The prevalence of obesity in this age-group was 4% by both criteria. The difference in prevalence of obesity in Kainuu and Turku was statistically significant. The prevalence of overweight boys was higher in Kainuu than in Turku and the difference grew as children approached school age.

Conclusions

Our study indicates that children’s overweight is a health problem in Finland, especially among school-aged children. The use of different criteria for the definitions of overweight and obesity has an impact when defining how many children are actually overweight. Newly published Finnish growth charts and growth references will help to define obesity and detect children’s overweight and obesity more sensitively than a weight-for-height assessment.