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Results of primary health care in Matlab, Bangladesh
Prevention of anaemia in women of child-bearing age
Stability of potassium iodate as an additive to salt
The authors believe that iron supplementation was the major factor responsible for the observed improvement in iron status that was found in the Matlab population surveys [1]. However, they do not prove it, because there was no true control group and other interventions were also occurring. Nevertheless, the data illustrate that the Matlab primary health-care programme, which included iron supplementation, was effective, and this should be an additional stimulus to the development of similar programmes in other countries. Another paper recently published in Lancet describes a decline in maternal mortality in the same population but cautions that the intervention programmes rely, at the very least, on the functioning of the entire health-care system and on effective referral and communication strategies to promote specific behaviours. It was noted that “One indicator will not be sufficient to elucidate the complex nature of such programmes, and various assessment techniques and indicators are required” [2]. Even if iron supplementation alone were sufficient to achieve the specific goal of correcting iron deficiency, it would not be a substitute for the other health measures in the Matlab programme.
References
1. Stoltzfus RJ, Chakraborty J, Rice A, de la Brière B, de Francisco A. Plausible evidence of effectiveness of an iron-supplementation programme for pregnant and post-partum women in rural Bangladesh. Food Nutr Bull 1998;19:197-204.
2. Ronsmans C, Vanneste AM, Chakraborty J, van Ginneken J. Decline in maternal mortality in Matlab, Bangladesh: a cautionary tale. Lancet 1997;350:1810-4.
Nevin S. Scrimshaw Senior Advisor UNU Food and Nutrition Programme Boston, MA, USA
The paper by Brabin et al. [1] in this issue of the Food and Nutrition Bulletin, consisting of an epidemiological cross-sectional study of women attending health posts and post-partum centres in Mumbai, India, points out very clearly several important and commonly observed facts regarding the haematological status of women of child-bearing age, particularly but not exclusively in the developing world. The following points are noteworthy from the policy point of view.
The prevalence of anaemia among both pregnant and non-pregnant women is extremely high (80% and 82%, respectively). Anaemia was defined on the basis of the World Health Organization proposed cut-off points of 110 g/f. haemoglobin for women in early pregnancy (<15 weeks gestation) and 120 g/L for non-pregnant women. The fact that even with a cut-off 10 g/L lower for early pregnancy, the prevalence of anaemia is as high in this population as it is among non-pregnant women suggests either that gestational haemodilution occurs early or that even the small demands of erythropoietic nutrients early in pregnancy will produce anaemia.
The absence of severe anaemia (<80 g/L) is important to note, even when mean haemoglobin values ranged from 97 to 114 g/L. The distribution of haemoglobin values shown in figure 1 is skewed to the right, except for the post-partum group, which shows a very symmetrical distribution. In this group, the proportion of women with haemoglobin levels <90 g/L is lower than in non-pregnant women or women in early pregnancy. This finding would appear paradoxical, because post-partum women generally are more anaemic than non-pregnant women. A possible explanation for this finding could be that supplementation with iron and folate during pregnancy temporarily improved post-pregnancy haematological status. This interpretation may be supported by the apparently small effects of multiparity. On the other hand, pregnancy appears to have a long-term effect on haemoglobin levels, as evidenced by higher haemoglobin levels among women who have never been pregnant, women with “no live births,” and women with “0 years since first pregnancy” than among the other three groups (table 1).
The results of multivariate analysis, including as independent variables women’s education, socio-economic status, number of pregnancies and live births, and age at menarche, explain only 16% of the variance in haemoglobin levels, leaving a large proportion of unexplained variance according to this model. Unfortunately, there is no information on biochemical indicators that could point in the direction of possible causes of low haemoglobin, such as meal composition, cooking methods, overall dietary intakes, infection rates, or even approximate menstrual blood losses, that are expected to account for most of the rest of the variance. Even though the authors do not speculate on causality, their discussion and recommendations suggest that underlying the problem is poor diet, leading most probably to iron and vitamin A, and possibly to folate and/or vitamin B12 deficiencies. In spite of these limitations, education, reproductive history, and age at menarche (as a surrogate for general nutritional status before and during puberty) are significant.
From these salient facts, the authors suggest that policies directed to improve the health and education of girls and the survival of children, reduce the number of pregnancies, and provide iron + folate supplementation during pregnancy are important to reduce the high prevalence of anaemia in the women of Mumbai. However, they acknowledge that these measures may have only a limited impact, and go a step further in their recommendations: “Health promotion to improve the diet of girls and iron supplementation in adolescence are required to redress nutritional deficits and, in the longer term, to reduce anaemia in older women of reproductive age...governments are starting to draw up national policy guidelines to improve adolescent sexual and reproductive health. Nutritional information and supplementation should be included in these policies, and every effort should be made to link supplementation to other interventions reaching young girls.”
Experimental animal, clinical, and population studies strongly suggest that community-based, preventive iron + folate supplementation, ideally combined with other nutrients deficient in the diet (e.g., vitamin A) should be targeted to vulnerable groups, in particular to small children and women of reproductive age (whether or not they are pregnant). This strategy could be implemented in the short term in areas where food-based approaches (i.e, food fortification and significant dietary improvement) cannot be achieved in the short or medium term. Focusing on fertile adolescents and adult women, the purpose of this strategy is to complement all other possible strategies, pertinently suggested by the paper by Brabin et al., but with the further aim that all women enter pregnancy with adequate iron reserves and a superior folate nutritional status.
The findings of the study of Brabin et al. suggest that iron + folate supplementation should start before pregnancy, and at least as early as possible during pregnancy. Providing 100 tablets of iron + folate late in pregnancy and without any mechanism that will promote their proper ingestion has proven, at most, only minimally effective. Effective preventive supplementation is most likely to occur through community action in coordination with the health posts and post-partum centres. Several trials in which schoolteachers provided weekly iron + folate tablets to schoolgirls (and boys in some cases) throughout the school year are demonstrating an improvement in iron nutrition, including the correction of moderate anaemia (as seen in Mumbai women) and, most importantly, a progressive and safe increment of iron reserves [2, 3] (B. Torun, personal communication, 1998; P. Winichagoon, personal communication, 1998).
Similarly, in women of childbearing age, the results of ingestion of one tablet a week containing 60 mg of iron and 250 mg of folate in the course of seven months, for a total of 30 tablets, were as good as or better than the results of daily ingestion of tablets of the same composition but only for the first three months of the total seven-month trial (totaling 90 tablets) [4].
Equally important is the information and motivation of the whole community through mass media and the formation of community groups (e.g., based on educational, religious, industrial, and market activities), and especially women’s groups, that can ensure the weekly ingestion of tablets by any woman who may become pregnant, and to double the dose as soon as pregnancy occurs (not waiting until the second or the last trimester of pregnancy). Coverage of the vulnerable population can also be increased in this fashion.
Several studies of pregnant women clearly indicate that initial haemoglobin concentration is the most important determinant of haemoglobin concentration at term, and that the duration of supplementation is more important than the dose of iron. Thus, the better the pre-pregnancy iron nutritional status, the more effective iron + folate supplementation during pregnancy can be. Ideally, women should enter pregnancy with 300 mg of iron reserves. Very few women in the developing world and almost half the women in industrial countries do not have these reserve levels. Currently, if women are already clearly anaemic during pregnancy (haemoglobin <90 g/L), they are treated by daily administration of iron. This practice should be continued and carefully evaluated, especially when haemoglobin levels are lower than 80 g/L. However, several studies suggest that supervised weekly iron supplementation with proper doses covering at least 15 weeks during pregnancy can be almost as efficacious as daily supplementation [4-8].
In conclusion, this paper provides strong support for targeting interventions for the prevention of anaemia in the community as a whole and especially in pubertal, adolescent, and mature fertile women and not concentrating iron + folate supplementation strategies only on pregnant women during the second or third gestational trimesters. In most developing country settings, iron + folate supplementation restricted to or starting during the last half of pregnancy has proven ineffective [9-11].
References
1. Brabin L, Nicholas S, Gogate A, Gogate S, Karande A. High prevalence of anaemia among women in Mumbai, India. Food Nutr Bull 1998;19:205-209.
2. Tee ES, Kandiah M, Awin N, Chong SM, Satgunasingam N, Kamarudin L, Miladi S, Dugdale AE, Viteri FE. School-administered weekly iron-folate supplements improve iron nutrition of Malaysian adolescent girls: feasibility, safety, and effectiveness. In: Proceedings of the Seventh Asian Congress of Nutrition. Beijing: Chinese Academy of Preventive Medicine, 1997.
3. Sinisterra-Rodriguez O, Valdés V, Chew F. Estudio de suplementación de sales de hierro en escolares en la República de Panamá. Proceedings of XI Congreso de la Sociedad Latinoamericana de Nutrición. Guatemala: Institute of Nutrition of Central America and Panama, 1997.
4. Viteri FE, Ali F, Tujague J. Weekly iron supplementation of fertile-age women achieves a progressive increment in serum ferritin. FASEB J 1998;10:A3369.
5. Atukorala TM, de Silva DR, Dechering WHJC, Dassenaeike TS, Perera RS. Evaluation of effectiveness of iron-folate supplementation and anthelmintic therapy against anemia in pregnancy - a study in the plantation sector of Sri Lanka. Am J Clin Nutr 1994;60:286-92.
6. Sloan NL, Jordan EA, Winikoff B. Does iron supplementation make a difference? Working Paper No. 15. Arlington, Va, USA: MotherCare Project.
7. Viteri FE. The consequences of iron deficiency and anaemia in pregnancy on maternal health, the foetus, and the infant. SCN News 1994;11:14-8.
8. Viteri FE. Iron supplementation. Nutr Rev 1996;55:195-209.
9. World Health Organization. Iron supplementation during pregnancy? Why aren’t women complying? A review of available information. Geneva: WHO Maternal Health and Safe Motherhood Programme, Division of Family Health, 1990.
10. World Health Organization. The prevalence of anaemia in women. A tabulation of available information. Geneva: WHO Maternal Health and Safe Motherhood Programme, Nutrition Programme, 1992.
11. Gillespie S, Kevany J, Mason J, eds. Controlling iron deficiency. ACC/SCN State of the Art Series, Nutrition Policy Discussion Paper No. 9. Geneva: World Health Organization, 1991
Professor Fernando Viteri
Department of Nutritional Sciences
University of California, Berkeley
Berkeley, CA, USA
The research by L. L. Diosady, J. O. Alberti, M. G. Venkatesh Mannar, and S. FitzGerald published in this issue of the Food and Nutrition Bulletin [1] and the earlier paper on the same topic published in the Bulletin [2] merit comment. The investigators invested a great deal of effort in the technical aspects of the research, including the laboratory procedures and careful control of artificial environmental conditions. Nevertheless, the narrow scope of the experimental plan, which considers only two climatic conditions (40°C at 100% relative humidity and 40°C at 60% relative humidity) severely limits the usefulness and potential application of the research findings.
Extensive areas in many developing countries with less drastic conditions of environmental temperature and humidity are heavily populated by people suffering from iodine-deficiency disorders. It would have been a valuable additional effort not only to use samples of salt from many countries, but also to include climatic conditions simulating medium and highland climates in countries such as Ecuador, Peru, Bolivia, Guatemala, Colombia, Nepal, and many others. It is my concern that this failure also to test stability under less extreme environmental conditions results in an unduly exaggerated view of the problem of iodate iodine instability. Readers not fully familiar with the variety of climatic situations in developing countries mentioned above may wrongly infer that most of the salts produced and consumed in developing countries are stored under the conditions of temperature and humidity tested in the study in question and therefore would require special low-density polyethylene bags. In actual practice worldwide, this special packaging requirement has not proved necessary in the many areas with milder climates.
As a historical footnote, it is appropriate to recall the original stability trial carried out in Guatemala in the 1950s [3]. Crude sea salt produced by solar evaporation was iodized in a plant at a production site by adding a premix containing one part of potassium iodate and nine parts of calcium carbonate. The amount added was adjusted to give a final product with approximately 1 mg of iodine per 10 g of salt. A 50-kg sample was then stored in a hemp fibre sack in an open room from January through August 1954 in the humid tropical lowlands. This period included four months of the dry season and four months of the rainy season, with an average humidity of 70% and 84%, respectively. The environmental temperature averaged around 25°C, ranging from 20° to 32°C.
The initial moisture content of the samples was 4.1%, and the final values in August, a rainy month, were 4.6% for the top layer, 4.9% for the middle, and 5.8% for the bottom of the sack. Only 3.5% of the iodine was lost during the eight months. No significant redistribution of the added iodate among the layers was observed. The authors concluded that their observations were of practical public health significance to those countries in which iodine deficiency is a problem, and iodization of salt by conventional methods is impractical for environmental reasons and protective packaging is economically or culturally unacceptable.
On the basis of these findings, the Institute of Nutrition of Central America and Panama (INCAP) successfully promoted the addition of potassium iodate to all salt for human consumption. In 45 years the prevalence of endemic goitre among children in Guatemala dropped from 38% to 5% [4]. The addition of potassium iodate has become the standard means of adding iodine to salt throughout the developing world and is widely promoted by the World Health Organization and UNICEF in their successful campaign to prevent iodine-deficiency disorders. No problems have been reported due to excessive loss of iodine, but a problem arose in Zimbabwe for the opposite reason. In determining the level of iodate to add to the salt, potential losses were severely overestimated. As a result, some subjects received too much iodine and experienced symptoms of thyrotoxicosis [5,6]. It is unfortunate that the results of the above INCAP study and two other studies cited in the first of the two papers by Diosady et al. showing losses of 6% to 10% in 12 months were not taken into consideration [7, 8].
It should be very clear that with the ambient conditions prevailing in most countries, the loss of potassium iodate, even from crude moist salt without moisture-proof packaging, is so small that it has been no obstacle to the use of potassium iodate for salt fortification in developing countries worldwide.
References
1. Diosady LL, Alberti JO, Venkatesh Mannar MG, FitzGerald S. Stability of iodine in iodized salt used for correction of iodine-deficiency disorders. II. Food Nutr Bull 1998,19:239-249.
2. Diosady LL, Alberti JO, Venkatesh Mannar MG, Stone TG. Stability of iodine in iodized salt used for correction of iodine-deficiency disorders. Food Nutr Bull 1997;18:388-96.
3. Arroyave G, Pineda O, Scrimshaw NS. The stability of potassium iodate in crude table salt. Bull WHO 1956;14:183-5.
4. Scrimshaw NS, Franco LV, Arellano R, Sagastume C, Méndez JI, de León R. Efecto de la yodación de la sal sobre la prevalencia de bocio endemical en niños escolares de Guatemala. Boletín de la Oficina Sanitaria Panamericana 1966;60:222-8.
5. Stanbury J, Ermans AE, Bourdoux P, Todd C, Oken E, Tonglet R, Vidor G, Braverman LE, Medeiros-Neto G. Iodine-induced hyperthyroidism: occurrence and epidemiology. Thyroid 1998;8:83-100.
6. Todd CH, Allain T, Gomo ZAR, Hasler JA, Ndiweni M, Oken E. Increase in thyrotoxicosis associated with iodine supplementation must be monitored at the population level in iodine deficient areas. Thyroid 1995;346:1563-4.
7. Chauhan SA, Bhatt AM, Bhatt MP, Majeethia KM. Stability of iodized salt with respect to iodine content. Res Industry 1992;37:38-41.
8. Zingon Institute. Experiment report on long-lasting iodized salt. Hubei, China: Zingong Design and Research Institute for Well and Rock Salt Industry, 1992.
Guillermo Arroyave
San Diego, CA, USA
