Impact of using nationalv. international definitions of underweight, overweight and obesity: an example from Kuwait

Abstract

AbstractObjectiveTo compare the classification of overweight, obesity and underweight using internationalv. national approaches in Kuwaiti adolescents.DesignAssessment of underweight, overweight and obesity using a national approach (based on Kuwaiti reference data for BMI-for-age) was compared with assessments obtained using three international approaches: the Coleet al.and International Obesity Task Force (IOTF) definitions of thinness and of overweight and obesity (Cole-IOTF); WHO 2007; and US Centers for Disease Control and Prevention (CDC) 2000 reference data and definitions. The degree of agreement between the different methods was assessed using the weightedκstatistic (κw).SettingTwo randomly selected public intermediate schools in Kuwait City.SubjectsA total of 499 10–14-year-old Kuwaiti adolescents.ResultsPrevalence of overweight and obesity using Kuwaiti reference data (36·7 %; 95 % CI 32·4, 41·1) was significantly lower than that obtained using international approaches – Cole-IOTF (44·7 %; 95 % CI 40·3, 49·2), CDC 2000 (44·9 %; 95 % CI 40·5, 49·4) and WHO 2007 (50·5 %; 95 % CI 46·0, 55·0) (P< 0·01). All three international approaches showed almost perfect agreement: IOTFv. WHO (κw= 0·82; 95 % CI 0·79, 0·85) and IOTFv. CDC (κw= 0·90; 95 % CI 0·87, 0·92). However, Kuwaiti reference data showed the lowest agreement with the three international approaches, the poorest being with WHO 2007 (κw= 0·54; 95 % CI 0·49, 0·59).ConclusionsCaution should be exercised when using recently collected national reference data and definitions while assessing underweight, overweight and obesity for clinical and public health applications.