Protocol for validating simple measures of body fatness and physical activity of children in twelve African countries : the ROUND-IT Africa study

Body fatness and physical activity (PA) among children should be measured accurately to address the pandemics of obesity and physical inactivity. Limited accurate PA data exist in the African region, and crude proxy measures of body composition (such as body mass index: BMI) and physical activity (such as questionnaires) may have limited most surveys and studies from the region. A stable isotope technique (deuterium dilution) and accelerometry provide ‘gold standards’ for validating measures of body fatness and PA, respectively. The consortium on “Reducing Obesity Using Nuclear Techniques to Design Interventions in Africa (ROUND-IT)” Study, therefore aimed to validate the accuracy of, 1) World Health Organisation’s (WHO) BMI-for-age as a means of assessing excessive body fatness; 2) the Physical Activity Questionnaire for Children (PAQ-C) as a means of measuring PA, and 3) to describe accelerometer-measured PA in a large African multi-country sample of children 6 – 11 years of age (n=2050). ROUND-IT Africa is a cross-sectional multi-centre study conducted in 12 countries (Benin, Ghana, Kenya, Mali, Mauritius, Morocco, Namibia, Senegal, Tunisia, Uganda, the United Republic of Tanzania and South Africa). Data collection began in April 2014 and was completed at the end of 2018. Height, body weight and waist circumference were measured using standard methods. Obesity was defined based on WHO’s BMI-for-age criteria. Body fatness was measured using total body water, and excess fatness determined using the criterion-referenced thresholds of >25% (boys) and >30% (girls). PA and sedentary behavior were assessed for 7 days in randomly assigned subsamples by accelerometry. The study was approved by local ethics committees in each participating country. Findings of the research, which will add to the existing body of scientific knowledge on African children, will be disseminated through journal publications, technical reports, conferences, and contacts with relevant non-governmental organisations, particularly the WHO