Consumption of iron-containing multiple micronutrient powders also resulted in increased diarrhea in a study in Pakistan [34] and increased hospitalizations in Ghana [35]. Thus, understanding the etiology of anemia and a balanced assessment of the potential risks and benefits of iron supplementation should be a part of program planning [36].
Fig. 4. Schematic illustration of the nutritional and nonnutritional causes of anemia in children and women. Developed by the authors based on results of a path analysis of anemia determinants in Uttar Pradesh, India [38].
In India, the prevalence of anemia is very high with little progress made over the past decade [37]; a better understanding of the etiology of anemia in context could help inform more appropriate approaches to its reduction. A recent study in Uttar Pradesh, India, examined the etiology of anemia in women and children using a state-representative survey [38]. This comprehensive study measured a range of genetic, environmental, infectious, and nutritional risk factors for anemia (Fig. 4). Results indicate that iron was an important contributor to anemia; 78% of children and 74% of women with anemia had iron deficiency anemia. Other direct and indirect determinants included inflammation, folic acid, vitamin B12, and vitamin A (serum retinol), as well as more distal factors, such as dietary diversity, household hunger, and water, sanitation, and hygiene, which work through effects on status indicators. In this population without malaria (<1%) and minimum intestinal parasites (<9%), iron and inflammation were strong determinants of hemoglobin concentration and anemia. The relationship between iron and inflammation, however, is not straightforward, and the extent to which iron and other nutritional interventions can be fully effective to address anemia is not clear. Nonnutritional causes of anemia may inhibit a response to iron interventions if not concurrently addressed. The type of analysis conducted with the data from Uttar Pradesh should be used to guide effective programs in populations where the contribution of nutritional and nonnutritional determinants to anemia prevalence may vary, such as settings with malaria or high proportions of genetic abnormalities.
Fig. 5. The ecological model applied to determinants of obesity in children living in First Nations communities in Canada, reproduced with permission from [41].
Overweight
There is still much to learn about the determinants and potential actions to prevent and control childhood overweight. As with stunting and anemia, the etiology of excess weight in childhood is complex and includes interactions among genetic makeup, intrauterine factors, the home and built environment, and behavioral factors [39, 40]. The interrelationship among these factors and how they may influence child weight is nicely illustrated for First Nations communities in Canada [41]. In this context, historical factors and persistent inequities dramatically influence many social and environmental determinants of overweight. An ecological model that frames biological and interpersonal determinants in this context, as illustrated in Figure 5, is helpful for identifying opportunities for action as well as potential barriers to their effectiveness. To date, few low- and middle-income countries have such in-depth analyses of the determinants of overweight in children needed to inform comprehensive approaches to addressing it.
Conclusion
Through the Sustainable Development Goals, the world has set the ambitious aim to achieve food security and end malnutrition in all its forms by 2030 [42]. Progress to achieving this goal for children is lagging, and the global prevalence of stunting, wasting, overweight, and micronutrient malnutrition remains unacceptably high. Several countries have made progress to address stunting, but many are unlikely to achieve the targets unless progress is accelerated substantially [7]. Childhood overweight is increasing in most regions, and with the limited data available, little progress has been made to addressing micronutrient malnutrition. Equally concerning is the lack of up-to-date representative data of the magnitude and distribution of malnutrition in all its forms and their determinants at national and subnational level. Beyond simply tracking progress, a more profound understanding of the contextual etiology of the various forms of malnutrition is urgently needed to inform effective action.
Disclosure Statement
The authors have no conflicts of interest to declare.
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