Validity of a simplified screening instrument for assessing overweight children in a dental setting: a cross sectional study

Abstract

Background: Obesity, with its rising prevalence among Canadians and its estimated cost of $2 billion annually in Canada, is no longer considered a cosmetic issue, but a major health issue that imposes a great burden on the healthcare system and economy. This cross sectional study aims to evaluate the feasibility of identifying the weight status of 6 to 11 year-old children in a university dental clinic using a simplified overweight screening instrument.

Methods: One hundred sixty eight healthy children were enrolled. Weight and height were measured and overweight/obesity status was assessed using two techniques: 1) the 2007 World Health Organization Body Mass Index (BMI)-for-age reference Tables, 2) simplified overweight screening instrument without BMI calculation. Measures of overall, positive, and negative percent agreement between the two approaches were computed.

Results: The children's average weight, height, BMI and BMI z-score were respectively 32.6 ± 9.5 kg, 133.8 ± 10.7 cm, 17.8 ± 3.2, and 0.4 ± 1.0. The overall, positive, and negative percent agreement between the two screening approaches were respectively, 89%, 100%, and 83%.

Conclusion: This study demonstrated the feasibility and parental acceptance of weight, height and BMI measurement in a dental setting and evidence that supports the validity of a new simplified approach to assess children's weight status without having to compute BMI.

Trial registration: NCT02637752 . Registered 18 December 2015.

Keywords: BMI (Body mass Index); Child growth; Childhood obesity; Weight.

Figures

Fig. 1

Example of assessing obesity status for a 10 years 2 month old boy, (Height:146 cm; Weight: 38 kg) with or without BMI calculation. a) Assessing obesity using WHO 2007 reference tables with BMI calculation. b) Assessing obesity using the simplified screening tool without BMI calculation. a) In the age row of 122 months, the BMI value for being overweight should be more than +1SD Z-score (19.16). This boy’s computed BMI (38 kg/1.4622 m = 17.8) is less than his screening unit grid of 19.161 and hence, he is not overweight. b) The age of this boy is between 10 and 10.5 years rows. In the row 10 years, the height is between 144.4 cm and 148.3 cm and in the row 10.5 years, his height is between 144.8 cm and 147.2 cm. The screening weight grids for these heights are, respectively, 38.5, 40.6, 39.4, 40.8 kg. The boy’s weight (38 kg) is below his screening unit grids and hence, he is not overweight. If his weight was 38.7 kg, he would be placed within the screening unit grids and hence, he would have been considered overweight. In contrary, as per the 2007 WHO table, his computed BMI (37.8 kg/1.4622 m = 18.15) is still below his screening unit grid of 19.161 and hence, he would have been considered not overweight