Body mass index assessment usingthree reference standards among school adolescents in Sokoto Metropolis, North-Western Nigeria

Abstract

Abstract:

Background: Under nutrition and overweight in children co-exist in developing countries and may persist into adulthood. Interpretation of body mass index (BMI), a useful measure of nutritional status in children requires age related reference standards, many of which were developed from different international sources. It is necessary to determine which of these reference standards is most suitable for use in the assessment of BMI distribution among adolescents in Nigeria.

Objective: To determine the prevalence of thinness, overweight and obesity using the World Health Organization (WHO), International Obesity Task Force (IOTF), and Centre for Disease Control (CDC) reference standards and assess their level of agreement amongst adolescents in Sokoto metropolis.

Methods: 800 students were selected through multi-stage sampling technique from secondary schools. BMI was classified according to three reference standards (WHO, CDC, IOTF). Data was analysed with SPSS version 22. The level of agreement between the reference standards in diagnosing nutritional status was assessed using Kappa statistics. Level of significance was put at p< 0.05.

Results: The prevalence rate of thinness was highest with the IOTF at 22.6% compared to 19.4%, and 19.6% by the WHO and CDC respectively. The prevalence rates of overweight and obesity were highest with the WHO reference standards at 7.0% and 1.3% followed by the IOTF (6.1%and 0.6%) and lowest with the CDC (5.8% and 0.3%). Substantial agreement was observed between WHO and IOTF (Kappa = 0.77), while the level of agreement was 0.68 for IOTF/CDC and 0.64 for WHO/CDC. All agreement statistics were significant (p < 0.001).

Conclusion: The WHO and IOTF reference charts may be more suitable for our population.

Keywords: body mass index, WHO, IOTF, CDC, Sokoto, adolescents