Science Communication: Transition and persistence in the double burden of malnutrition and overweight or obesity: Evidence from South Africa

Summary

The term double burden of malnutrition refers to the simultaneous occurrence of undernutrition and overweight or obesity within the same populations, households, or individuals. Focusing on the household level, we aim to investigate whether this nutritional status is temporary or persistent in South Africa. Our findings indicate that it is, in fact, a temporary occurrence, as most households experiencing the double burden of malnutrition during one survey period do not continue to do so in subsequent waves. Additionally, we analyze households that are overweight or obese (OVOB) and observe that these households tend to maintain this status over time, indicating a certain level of persistence. Lastly, we note that households experiencing the double burden of malnutrition are increasingly likely to be classified as OVOB over time.

Detailed summary

The double burden of malnutrition is partly attributed to the simultaneous progression of economic development and the nutrition transition. Consequently, while undernutrition remains stable or experiences only marginal declines, obesity is dramatically increasing in many countries. To examine this phenomenon and its dynamics, we use South Africa as an example. In 2020, the prevalence of stunting among children in South Africa was 27.4%, while the prevalence of overweight or obesity among women stood at 67.2%. This country faces the most severe obesity epidemic in sub-Saharan Africa, and undernutrition persists, particularly in its most impoverished communities.

Our analysis is centered on the household level. We define a ‘double-burdened household’ as one where at least one individual is overweight or obese, while at least one other household member is underweight. Our primary focus is to determine whether this nutritional status is persistent or temporary at the household level. Additionally, we introduce another category of household, namely, the ‘overweight/obese household’ (OVOB), defined as a household with at least one overweight or obese member but no underweight individuals, and for which we also aim to ascertain whether this status is maintained over consecutive survey periods or if it is a temporary occurrence.

We utilized data from five survey waves conducted by the National Income Dynamics Study (NIDS) by the University of Cape Town in South Africa. These surveys delve into the living conditions of individuals in South Africa and encompass questions related to economic activities, poverty, labor force participation, education, and health. Beginning in 2008, these surveys have been conducted every two to three years, with the most recent wave occurring in 2017. We incorporated data from all five survey waves, assigning a nutritional status to each individual based on their BMI. These individual measures allowed us to subsequently define the nutritional status at the household level.

Our results suggest that DBM is a transitory nutritional status, as it is more likely that a DBM household will not remain so from one survey period to the next. Furthermore, our analysis highlights specific characteristics associated with a higher likelihood of being double-burdened, including households with less educated heads, urban households, and ethnic minority households. In contrast, when examining the results for the other nutritional status under consideration, OVOB households, it appears that these households are more likely to maintain this nutritional status over time.

Additionally, our results demonstrate that DBM households are more likely to transition into OVOB households over time. These household-level findings are rooted in individual-level dynamics. In this paper, our objective was also to elucidate the factors at the individual level that contribute to the dynamics of nutritional status at the household level. Specifically, our findings reveal that the persistence of OVOB at the household level is primarily driven by individual-level persistence. In simpler terms, individuals who are overweight or obese within these households tend to remain so over time. For households transitioning from DBM to OVOB between survey periods, this suggests that underweight is decreasing, as a significant proportion of previously underweight individuals move towards a healthy weight status. While this might be considered an improvement in nutritional status for some individuals, it may not hold true for all household members, as some continue to struggle with overweight or obesity. Furthermore, in line with Barker’s hypothesis, it is not implausible that children who transition from underweight to normal weight may later develop chronic, non-communicable conditions such as overweight and obesity. This, in turn, could contribute to the escalating obesity epidemic over time.

The double burden represents a burgeoning public health challenge in developing nations, necessitating targeted policy interventions known as ‘double-duty actions’. These actions are designed to concurrently tackle issues of undernutrition, overweight, obesity, and diet-related non-communicable diseases. Double-duty actions may encompass both new policy proposals and the expansion of existing interventions initially focused on addressing a single aspect of malnutrition but now broadened to encompass the multiple facets associated with the DBM.

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