Prevalence of overweight and obesity among African primary school learners: a systematic review and meta-analysis

Abstract

Introduction: The increasing trend in the global prevalence of childhood overweight and obesity presents a major public health challenge. This study reports the results of a systematic review and meta-analysis to estimate the prevalence of overweight and obesity among primary school learners residing in Africa according to the different body mass index criteria and population level characteristics.

Methods: A search of multiple databases was conducted to identify relevant research articles published between January 1980 and February 2017. Random effects models were used to pool prevalence data within and across population level characteristics after variance stabilization through arcsine transformation (PROSPERO registration number CRD42016035248).

Results: Data from 45 studies across 15 African countries, and comprising 92,379 and 89,468 participants for overweight and obesity estimates were included. Estimated overweight and obesity prevalence differed significantly across criteria: 10.5% [95% confidence interval, CI: 7.1-14.3] and 6.1% [3.4-9.7] by World Health Organization; 9.5% [6.5-13.0] and 4.0% [2.5-5.9] by International Obesity Task Force; and 11.5% [9.6-13.4] and 6.9% [5.0-9.0] by Centre for Diseases Control, respectively (p = 0.0027 for overweight; p < 0.0001 for obesity). Estimates were mostly higher in urban, and private schools, but generally similar by gender, major geographic regions, publication year and sample size. Substantial heterogeneity in the estimates across and within criteria were not always explained by major study characteristics.

Conclusion: Overweight and obesity are prevalent among African primary school learners, particularly those attending urban, and private schools. The results from this meta-analysis could be helpful in making informed decisions on childhood obesity prevention efforts in African countries.

Keywords: Africa; Meta‐analysis; Overweight; learners.

Figure 1

PRISMA flowchart for the study selection process.

Figure 2

Forest plot of the prevalence of overweight by major diagnostic criteria. Black boxes represent the effect estimates (prevalence) and the horizontal bars about are for the 95% confidence intervals (CIs). The diamond is for the pooled effect estimate and 95% CI.

Figure 3

Forest plot of the prevalence of obesity by major diagnostic criteria. Black boxes represent the effect estimates (prevalence) and the horizontal bars about are for the 95% confidence intervals (CIs). The diamond is for the pooled effect estimate and 95% CI.

Figure 4

Funnel plots for the assessment of publication bias in studies of prevalent overweight (upper panels) and obesity (lower panels) by the World Health Organization (left column), International Obesity Task Force (middle column) and Centers for Diseases Control (right column) criteria, in African learners. For each figure panel, the dots are the arcsine transformed prevalence estimates of individual studies (horizontal axis) plotted against their standard error (vertical exist). The dotted vertical blue line is for the observed pooled prevalence estimates, while the dotted vertical black line bisector of the angle formed by the two upward converging lines, indicated where the pooled estimates should have been in the absence of publication bias. The p‐value from the egger test of bias is also shown.