Reproducibility of two, three, four and five 24-hour recalls in peri-urban African adolescents in the North West province

Background: The objective was to determine the reproducibility of two, three, four and five repeated 24-hour recalls among peri-urban African adolescents. Method: A prospective study design was used within the multidisciplinary PhysicaL Activity in the Young (PLAY) study. Eighty-seven Grade 9 learners (59 girls and 28 boys, aged 10-18 years) with a mean age of 14.7 ± 1.5 years, who had completed five 24-hour recalls, were investigated. The learners were from Seiphemelo Secondary School in Ikageng, a peri-urban area in the North West province of South Africa. Reproducibility coefficients (RCs) and 95% confidence intervals (CIs) were calculated, using the intraclass correlation coefficient formula for transformed values of selected nutrients and food groups, for two, three, four and five repeated 24-hour recalls. The RCs and 95% CIs were compared in order to identify the optimum number of 24-hour recalls to give the best reproducibility results. Results: The RCs were nutrient- and food-group sensitive and ranged from 0.25 (riboflavin) to 0.6 (carbohydrate). Although differences were not statistically significant, RCs for four and five 24-hour recalls were higher than those obtained for two and three 24-hour recalls. For most nutrients and food groups, four 24-hour recalls gave the highest RCs, with non-significant differences overall between the four and five 24-hour recalls. Conclusion: The results suggest that four 24-hour recalls would be sufficient to provide acceptable reproducibility of reported food group and nutrient intakes among peri-urban African adolescents.