Trajectories of the double burden of malnutrition and social inequality in 6–12-year-old South African children: The NW-child study

A longitudinal analysis of 333 South African children found persistent differences in malnutrition measures between groups of low and high socioeconomic status from Grade 1 through Grade 7. The study abstract reports that children in the low-SES group were more frequently classified as at risk of stunting or being underweight, while children in the high-SES group showed higher prevalence of overweight or obesity when assessed by several measures. The pattern was observed at the population level rather than for each individual child.

The researchers used data collected from 2010 to 2016 through the North-West Child-Health-Integrated with Learning and Development longitudinal study. The same children were followed at three ages: Grade 1, when participants were 6–7 years old; Grade 4, when they were 9–10; and Grade 7, when they were 12–13. The cohort included 186 children classified as low SES and 147 as high SES, with boys and girls analyzed in each group. Undernutrition risk was assessed using height-for-age, weight-for-age, and body mass index-for-age, while overnutrition was assessed using body mass index-for-age, waist-to-height ratio, and body fat percentage.

Across Grades 1 to 7, low-SES children had a significantly higher risk of being at risk of stunting and underweight, with all reported p-values at or below 0.001. Their relative risk of classification as at risk of stunting was at least 178%, and the relative risk of being underweight was at least 259%. Conversely, low-SES children had lower measured prevalence of overweight or obesity by body mass index-for-age, waist-to-height ratio, and body fat percentage. The reported reductions in relative risk were at least 68% for waist-to-height ratio, at least 68% for body fat percentage, and at least 71% for body mass index-for-age, with all p-values at or below 0.003.

Some patterns changed during puberty. Stunting-risk prevalence increased by 24.1% among pubertal boys. Among pubertal girls, the higher risk of classification as at risk of stunting and the lower risk of overweight or obesity by body mass index-for-age each lost statistical significance over time. The abstract describes these results as indicating a population-level, but not individual-level, double burden of malnutrition, characterized by persistent undernutrition risk among low-SES children and greater overnutrition among high-SES children. Because the available evidence is the study abstract, it does not provide the full methods, detailed statistical estimates, or results needed to assess individual-level classification across all measures or the study’s wider limitations.

Subject of Research: Longitudinal differences in malnutrition measures by socioeconomic status among South African children aged 6 to 13

Article Title: Trajectories of the double burden of malnutrition and social inequality in 6–12-year-old South African children: The NW-child study

Article References: van Niekerk, E., Pienaar, A. E., & Monyeki, M. A. (2026). Trajectories of the double burden of malnutrition and social inequality in 6–12-year-old South African children: The NW-child study. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07548-1

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07548-1

Keywords: child malnutrition, South Africa, longitudinal study, socioeconomic status, stunting, underweight, overweight, obesity, body composition, puberty, Trajectories, double