Comparison between Body Mass Index and Waist Circumference in 7-11 year old Swedish children

Abstract

Background and aim: Pre-obesity and obesity in children and adolescents is a severe public health problem, and is now considered a worldwide epidemic by the World Health Organization. This is of great concern since childhood obesity seems to pass through to adulthood resulting in an onset of obesity-related chronic disease in adult life, increasing morbidity and mortality. Body Mass Index (BMI) is commonly used to assess overweight and obesity. However, as it does not distinguish between body weight associated with muscle and body weight associated with fat it may lead to some error in classifying obesity and overweight. Waist Circumference (WC) is an alternate measure of abdominal adiposity and it is related to be a strong predictor of abdominal fat, being oftentimes used as an indirect screening marker for abdominal obesity applied in epidemiological studies along with the BMI. Methods: As part of the second phase of the Childhood Obesity Surveillance Iniciative study (COSI II Sweden), 1097 children aged 7-11 were evaluated with regards to anthropometric variables of weight and height, as well as WC. Nutritional status was assessed by calculating the BMI. Results: The prevalence rates for overweight (pre-obese and obese) using the WHO cut-off values for the BMI ranged from 22.9% in boys to 17.8% in girls. 77.1% of boys were classified as having normal weight while 17.3% were pre- and 5.6% obese. As for the girls 82.2% were classified as normal weight,14.2% pre-obese and 3.6% obese. Using the WC cut-offs 94.1% of boys were classified with a normal WC, while 5.4% were classified as pre-obese and 0.5% obese. A similar tendency was verified in girls with 92.2% classified with a normal WC while 5.9% were pre-obese and 1.2% obese. Conclusion: Overweight prevalence was lower when using the WC rather than BMI. Further research is needed to assess the veracity of these results. There is a need to create adequate age and gender-specific cut-off points in order to produce specific WC percentiles for swedish children.