|Delivery of Oral Doses of Vitamin A Deficiency and Nutritional Blindness: A State-of-the-art Review - Nutrition policy discussion paper No. 2 (UNSSCN, 1987, 120 p.)|
Susan J. Eastman
Susan J. Eastman is a consultant based in New York, recently working with UNICEF in preparing vitamin A policy options.
The West/Sommer paper presents a wealth of data supporting the use of vitamin A dose delivery as a critical intervention for xerophthalmia control. With the findings emerging from Indonesia demonstrating a positive correlation between vitamin A supplementation and child survival, the effects of vitamin A programming have yet to be fully determined. To be thorough, the authors review numerous and divergent findings from a variety of field studies. Their paper allows the manager to have the technical background leading to the use of the WHO-recommended standard dose of vitamin A. On the other hand, the authors do not address certain technical issues relevant to current program development, e.g. identifying the xerophthalmia problem in a country. Some details on such issues are given here.
In presenting studies on the safety of vitamin A supplementation, much of the analysis concerns the effects of doses higher than the standard recommended by WHO. Data from those studies led to the decision to recommend the 200,000 IU (rather than, for example, the 300,000 IU) dose. Although these findings are important in emphasizing the need for program supervision, they are less relevant in the choice of the delivery itself.
Secondly, in looking at the issue of vitamin A absorption the emphasis is on the limitations of the body to absorb the oral vitamin A, in both the ill and healthy child. However, the information needed by the policy maker is that - given the limitations - there is enough absorbed to be effective in the control of xerophthalmia.
Finally, in presenting the dramatically different results of vitamin A oral dosing on serum retinol levels, the limitations of that indicator as an accurate assessment of body stores of vitamin A should be appreciated. Instead, the program manager is presented with conflicting results on which to base key decisions.
Although it was not the purpose of the paper to help the manager make a decision on whether or not to intervene in vitamin A, it is worth suggesting when, where and how that decision might be made. Some suggestions follow.
A problem must first be identified. Presumably limited information is available on xerophthalmia in the country. Methods of gathering additional data include:
- examining the records of blind schools on the etiology of blindness in their students
- an analysis of medical records from hospitals and clinics
- rapid assessment surveys in the field
- national prevalence surveys
Choice in methodology depends on technical and financial resources available. Once the extent and location of the problem are identified (or suggested), decisions can be made concerning the degree to which program intervention is required. Criteria for determining whether or not a significant public health problem exists are given in the paper by West and Sommer, based on WHO guidelines.
The discussion does not distinguish between countries where there is clearly a high prevalence of xerophthalmia (i.e. Asia), to countries where there are clearly high rates of severe protein-energy malnutrition and measles complications, although data on xerophthalmia are limited (i.e., Africa), and countries which have reported low levels of vitamin A deficiency and moderate protein-energy malnutrition without significant rates of xerophthalmia (i.e., Latin America). How does periodic dosing with vitamin A apply to these different situations? To what degree are programs and protocols similar in such varying contexts?
The decision-makers must then be directed to use the guidelines by the International Vitamin A Consultative Group (IVACG) as well as the WHO listings of priority countries.
Specific target groups and their respective treatment protocol need to be clearly outlined. The paper refers to preschoolers (i.e., under six-years-old) as well as non-pregnant or lactating women, and presents the most recent vitamin A dose delivery formally endorsed by WHO. Definition of the preschool population has varied: under-five (to 60 months), under-six (to 72 months), and through six years (to 84 months). Furthermore, when and how often do you dose non-pregnant women (i.e., lactating or not, for treatment or prophylaxis)? Finally, what is the preferred dose delivery interval in periodic dosing? The recommendations is every four to six months, although twice - yearly is often used. The data presented in the paper would support every four months; operational challenges generally limit delivery to every six months.
Both research studies in child survival and the data demonstrating Africa as a continent is in need of immediate vitamin A intervention indicate that alternative vitamin A dose protocols may need to be considered. At present, the manager should depend on the WHO guidelines presented in the paper, but should also be aware that these are under review, with the possibility of expanding the treatment protocol and definition target groups.
To assist management decisions, the authors present three strategies for dose distribution used in vitamin A intervention: medical, targeted, and universal. The suggestion is that a combined medical and targeted would maximize the cost efficiency in reaching those considered at most risk. The paper itself focuses on the preventive capability of vitamin A supplementation, perhaps paying too little attention to the need for medical treatment in clinic and hospital patients. In emphasizing primary health care and village-level interventions, the hospital pediatric ward can be neglected (in terms of appropriate vitamin A supplies and training of medical staff). Since the sick child is at most risk of the deficiency, the clinic situations must be covered for the sake of expediency, efficiency, and care.
It is an uncomfortable fact that the coverage of most health systems in the developing world do not reach the majority of their country's children. Thus, in focusing on a medical and even targeted intervention, we are accepting the limitation of current reality. This does not minimize the need of the innovative manager to look around to determine ways to reach special risk groups. An effective strategy is the multi-media approach used in Lombok Indonesia, which demonstrated that with community participation and communication, there was a reduction in disease and increase in program coverage. Although this could be considered problematic in terms of sustainability, in fact it allows the health staff to work with whole communities rather than attempting to track individual children on a six-monthly basis, In recommending this model to all its field managers, Indonesia has demonstrated the possibility for integration yet innovation.
The paper examines at length measures to determine program impact in terms of change in prevalence of disease. Techniques to evaluate program operations themselves are also important. For example, the authors emphasize the need to look at program coverage in terms of at-risk groups, and offer varying strategies to reach them (i.e., targeted delivery). However, there needs to be in place a surveillance or monitoring system to routinely inform the individual managers the extent to which such critical groups are being reached.
Determining costs for vitamin A programming depends on assumptions made. The authors present the principle of marginality, which suggests that costs not attributable to the vitamin A program itself need not be considered part of the equation in determining program costs. This is a liberal perspective on costing, and can be used to support what then is an incredibly inexpensive intervention, i.e. averaging U.S. $0.015/capsule (fluctuating in terms of unit ordered and rate of foreign exchange). In using delivery costs to the field, the pricing has been assessed as high as $0.33 per dose. However, with the increased popularity of essential drugs programs - where a predetermined selection of drugs are routinely sent to the district health centers - the inclusion of vitamin A allows for a relatively reliable and sustained mechanism for getting the capsule to the field.
In presenting the periodic dosing as a recommended first-run intervention, less is said on the costs and benefits of food fortification with vitamin A and dietary modification. The paper reports that food fortification with vitamin A is relatively inexpensive, and that initial costs should be borne by the governments. Both of these are personal viewpoints not further substantiated. If the target population for food fortification can be considered an entire population, the costs per unit might be comparable but the program costs are relatively large and constant. Hence, in Central America, where fortification has been an effective intervention to increase serum retinol levels, a major factor leading to its demise has been the need for foreign exchange to procure the vitamin. So the cost becomes a critical issue. Secondly, whether or not the government, the industry, or the consumer should absorb the cost to improve both the nutrition and market value of the foodstuff is an open question for local policy makers to determine.
Dietary modification is considered a long-term yet essential component in xerophthalmia control. It generally refers to the need to assure vitamin A intake levels. However, in addition, fat and protein consumption must be assured to maximize the absorption and utilization of the vitamin. Three factors influence the body's vitamin A status: intake, absorption, and utilization. All three need to be of concern to those creating vitamin A programs. Nutrition education and horticulture are then critical components in any comprehensive approach to xerophthalmia control.
Finally, infection and vitamin A deficiency impact on each other in a relentless cycle. This synergistic relationship is not explored in the paper. The authors do insist on the intricacy of the problem in noting that severe protein-energy malnutrition, measles, diarrhoea, respiratory and other infections often precede or accompany corneal xerophthalmia. Hence, the prevention and treatment of them are important adjunct therapies.
In sum, the paper has given us the background to support the development of vitamin A programs and methods of assessing their impact, with specific operational issues less well defined. The paper rightly concludes that in vitamin A supplementation, we have both the technological promise and the operational challenge.