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Noguera, Viteri, Daza & Mora |
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Noguera, Viteri, Daza & Mora |
EVALUATION OF THE CURRENT STATUS OF
ENDEMIC GOITER AND PROGRAMS
FOR ITS CONTROL IN LATIN AMERICA
Costa Rica.The aspersion and dry-mix methods are used, the salt being fortified with potassium iodate. With the dry-mix method, use is made of a premix of potassium iodate with calcium carbonate in a proportion of one to nine.
The Ministry of Health, through the Department of Food Hygiene, and the Costa Rican Institute of Research and Teaching on Nutrition and Health are responsible for the surveillance and control of salt iodization.
No information is available on the control of salt samples taken in the last year.
Cuba.The necessary information is not available.
Ecuador.The aspersion and dry-mix methods are used. An aqueous aspersion solution contains 2.0 parts of potassium iodide to 1.0 part of sodium carbonate and 4.0 parts of dextrose.
For the dry-mix, a premix is used consisting of 1.2 parts of potassium iodide to 8.4 parts of calcium carbonate and 4.2 parts of sodium carbonate.
As established by the Ministry of Health, the Institute of Nutritional and Sociomedical Research (INIMS) is responsible for the control of salt iodization, in accordance with standards set by the Ecuadorean Institute of Standardization (INEN).
There are no recent data on the control of iodization, but it is known that floods in the salt-producing areas have had a highly adverse impact on both the supply and the control of iodized salt.
EI Salvador.The dry-mix niethod is used for fortification, with potassium iodate and calcium carbonate in a proportion of one to nine.
The institution responsible for the control of iodization is the Ministry of Health through its Department of Food Hygiene. A commission, made up of the Ministries of Economy and Public Health and Social Welfare, two industries engaged in the iodization of salt, a salt producer, and a representative of the Food Regulatory Institute, acts as advisory agency in the matters of production, marketing, and iodization.
An analysis of 303 samples from iodization plants performed during 1982 indicated that 90% of them did not contain iodine.
Guatemala. The dry-mix method is used, with a mixture of potassium iodate and calcium carbonate in a proportion of one to nine. The National Association of Salt Dealers is responsible for the iodization of salt, and the Ministry of Public Health and Social Welfare is responsible for supervision. A Coordinating Commission, composed of the Ministries of Health, Finances, and the Economy, the institute of Nutrition of Central America and Panama, and the General Association of Salt Dealers of Guatem ala, coordinates the different measures designed to implement program development.
The data available on iodization control for the period from October 1982 to March 1983 show that IOO% of the salt samples of Guatemalan origin and those imported from Costa Rica had concentrations of less than 60 ppm, which is the accepted lower limit of iodization; IO% of salt samples from EJ Salvador and 15% of those from Honduras also were below this limit. All (IOO%) of the samples of salt imported from Nicaragua were within the proposed limits of 60 to 100 ppm.
Honduras.The dry-mix method is used, with a mixture of potassium iodate and calcium carbonate in a proportion of one to nine.
The Ministry of Public Health is responsible for the program of iodization through the Departments of Food Control and Nutrition.
Analyses done on 267 samples from iodization plants and from I,576 retail outlets during 1982 showed an average value of 6.37 mg of iodine per 100 g of salt, a figure within the established limits of 60 to 100 ppm.
Nicaragua.Currently, two methods are being employed to iodize salt: the dry-mix method, using a mixture of potassium iodate and calcium carbonate in a proportion of one to nine, and the aspersion method, using potassium iodate in aqueous solution.
Responsibility for the control of salt iodization rests with the Ministry of Health through its Nutrition Area and Food Hygiene Office.
There is a National Salt Corporation (CONASAL), made up of representatives from the Ministries of Health, Commerce, and Foreign Trade, as well as representatives of the producers, processing plants, and private and state companies engaged in the salt indu stry. This Corporation functions as a coordinating/advisory organ in the orientation of policies and measures that help to maintain the salt industry and salt iodization at optimum levels.
No information is available after 1981 on the control of iodization.
Panama.The dry-mix procedure is employed, using potassium iodate and calcium carbonate in a proportion of one to nine. There is evidence that the installation capacity to iodize salt is not being adequately used.
The Ministry of Health is responsible for the control of iodization through its Departments of Food Control and Nutrition. The Panamanian Commission on Industrial and Technical Standards (COPANIT) oversees the labeling of foods packaged for human consump tion.
Thirty-six samples collected at seven iodization plants were analyzed in March 1983; 100% did not reach the levels established by law, and 53% either did not contain iodine or else had very low levels.
Paraguay.Paraguay, a net importer of salt, has set the compulsory level of salt iodization at 60 to 80 ppm.
Analyses of 77 salt samples taken in different parts of the country in 1983 yielded an average of 14 ppm; all the samples analyzed were below the levels established by law.
The Ministry of Health, through its Department of Nutrition and Laboratories, is responsible for the control of salt iodization.
Peru.The dry-mix procedure is employed. No stabilizer is used, and the premix is potassium iodate and salt.
The Ministry of Health, through its Center for Research on Nutrition and Food Control (CINCA), is responsible for the control of iodization. A Goiter Commission, composed of representatives from the Ministry of Health, through the General Bureau of Perso nal Health Care, the Executive Bureau of Noncommunicable Diseases, the Center for Nutritional Research and Food Control, the Peruvian University Cayetano Heredia, the Universidad Nacional Mayor de San Marcos, and the Department of Endocrinology of the Chi ldren's Hospital, functions as a technical advisory organ at the decision-making level of the Ministry of Health.
Currently, there is no control of the iodization of salt.
Uruguay.The dry-mix method is used, with potassium iodate. Responsibility for the control of salt iodization rests with the Ministry of Health. No recent data are available on the control of salt iodization.
A National Commission for the Study and Prophylaxis of Endemic Goiter (CONAPROBO), created by the Ministry of Health, serves as a scientific advisory body to the Ministry of Health on policies and measures aimed at the eradication of endemic goiter.
Venezuela.Venezuela uses the aspersion system, with potassium iodate. The Institute of Nutrition and the National Institute of Hygiene are responsible for the control of salt iodization and for monitoring its biological impact. No recent data are available on the control of iodization by the responsible institutions; however, the salt-producing industries have their own laboratories where quality control analyses are carried out, including iodization levels taken every hour. The results of analy ses performed at the plants are which the established levels (20 to 30 ppm), but the extent to which this salt is distributed effectively at sales outlets and among consumers is not known.
One of the recommendations emanating from the Workshop on the Study of Etiological Agents of Endemic Goiter, held recently in Caracas, was that a multidisciplinary National Goiter Commission should be created. Its technical function would be to implement and evaluate programs or activities aimed at the control of endemic goiter.
A comparison undertaken between production capacity and the actual production of iodized salt in 12 countries (see Table S) indicates that the salt is used anywhere from 8% to IOO% of the time, the average for the countries being estimated at S2%.
Annual Salt Production, Availability, Use, and Distribution (see Tables 8, 9, 10, 11, 12, and 13). Eleven of 15 countries are self-reliant in their production of salt to meet the internal demand, including human, animal, and industrial consumption. Two countries, Paraguay and Uruguay, are absolutely dependent on imports. Two others depend on salt imp orts to meet the internal demand: Guatemala, for human consumption, and Nicaragua, to meet the demand for salt in industrial use.
Analysis of the utilization of salt showed that in the 11 countries for which information was available, the proportions allocated to the different types of consumption vary widely. Thus, between IS% and 82% of the total is for human consumption; I l % t o 36 % is for animal consumption; and 3% to 53% is for industrial consumption.
Cost of Salt Iodization, Price to the Consumer, Consumption per Capita/Day, and Cost per Inhabitant/Year (see Tables 14, IS, and 16)
The estimated cost of salt iodization per metric ton in 14 Latin American countries ranged between US$0.58 and $l7.00, with an average of US$4.75/TM (0.5 c/kg). The exclusion of the two most extreme values reduces the range to between US$1.00 and US$8.00 and the cost per MT to US$4.47 (0.45 c/kg).
The average cost of I kg of iodized salt to the consumer in 15 countries was US$0.20, with a range between US$0.05 and US$0.33.
The average consumption of salt per capita/day was estimated for 14 countries at 9.76 g/day, with a range between five and 14 grams per capita/day.
The estimated consumption of salt per person/year would be on the order of 3.5 kg. If the average cost of iodization of one kg of salt is US$O.OOS, the cost per person per year would be US$0.0175. (lt. decreases to US$0.0158 if the two extreme values for the cost of iodization are excluded.)
The very wide range of costs of iodization observed (US$0.58 to US$17/MT) is due to the fact that in large industries the cost of iodization basically includes only the value of the iodine compound, whereas other plants include additional expenditures. T he highest cost noted (US$17/TM in Nicaragua) is the result of the addition of a net profit margin at all points in the production-iodization-packing-marketing chain. This is to serve as an incentive to anyone who engages in these activities. Even with this cost structure, however, the price of salt experiences an increase of only US$0.017 per kilogram, and the final price for one kg of iodized salt to the Nicaraguan public is US$0.22-very near the regional average.
Discussion
Sixteen of the 18 countries surveyed mandate salt iodization in order to increase iodine intake and control endemic goiter and cretinism. In eight of the countries, salt iodization is compulsory both for human and for animal consumption. With the except ion of Uruguay where legislative coverage is limited to endemic areas, all other countries maintain programs that are national in scope.
At present, Cuba and Chile are the two countries that have no legislation for the iodization of salt or any other measures to control endemic goiter. ln Cuba, available information indicated that goiter is endemic in the region of Baracoa but not in Havan a. In Chile, the most recent information shows a goiter prevalence of 24.8% in three communities. ln neither instance does the information reflect the general situation in the countries. lt. does show, however, that there are communities with endemic goi ter, leading one to suppose that a similar situation may exist in other communities or regions of the country with similar characteristics (mountainous region in Cuba and Andean communities in Chile).
Some countries where salt iodization is not compulsory for animal consumption face additional problems. According to information uncovered by the survey, portions of the population, especially those in rural areas who are engaged in livestock-raising, co nsume salt processed for animal consumption. Thus, these countries must devise further control and distribution measures.
Table 2 shows the results of the most important studies on goiter prevalence done in 18 countries of Latin America.
In countries where studies were completed prior to and after iodization, it is possible to measure the impact that these programs have had at the population level. ln most of the countries analyzed, an appreciable reduction can be noted in the prevalence of goiter after inauguration of the program. ln others, however, the prevalence remains high, with no apparent reduction after the start of iodization, and there may even be increases in goiter prevalence. An example of the first situation is Bolivia, wh ere in 1981 the overall prevalence in the school population at the national level was 60.8%, ranging from 43% to 75% in nine departments. In some areas of the Bolivian Highlands, a significant number of cretins were found. These findings may be closely associated with: (l) the various forms and sources of salt exploitation in the country; (2) the characteristics of the structure of the salt market, which involves many intermediaries; (3) insufficient or inadequate infrastructure for salt iodization and its effective control; (4) a failure to educate the population and obtain their active participation in programs for the prevention of endemic goiter and cretinism; and (S) the lack of emphasis placed on these programs at the technical level.
ln Venezuela, the findings showed a goiter prevalence of 13% in 1966, whereas in 1981 this figure was 21.4%. The increase cited may be explained by differences in the sampling framework in the two studies, in the type and standardization of the examiners in both periods, and in the goiter classification applied in the two surveys. Apart from the increase exhibited between the two surveys, attention is called to the fact that Venezuela, 13 years after having initiated a salt iodization program, presents a goiter prevalence in schoolchildren and adolescents even higher than 20%. Brazil poses a similar situation, since even 18 years after the start of compulsory iodization, 14.7% of the schoolchildren still have visible goiter. A larger number of schoolch ildren were found to have palpable and nonvisible goiters, which raises doubts as to the reduction in goiter prevalence between 1967 and 1975 (the 1967 survey included palpable goiter). This uncertainty points out the need for careful research on the pro cesses and impacts of the programs in order to establish the causes of the problems and to take action to correct them.
Only four countries in the region-Colombia, Costa Rica, Panama, and Uruguay-showed prevalences of less than 10%. In Colombia, however, the last evaluation was made 18 years ago and was limited to eight municipalities. Thus, there is no guarantee that th e information available can be extrapolated to the rest of the country. Furthermore, it is known that iodization control problems exist and that noniodized salt is marketed by small, clandestine producers in various parts of the country.
ln Argentina, Colombia, EI Salvador, Honduras, and Mexico, between 11 and 20 years have elapsed since the impact of the iodization programs has been evaluated. Except for Honduras, the other four countries either have no information available, or what th ey do have indicates serious problems in the control of iodization. These difficulties are particularly apparent in EI Salvador.
Colombia and Guatemala were the first two countries in Latin America to demonstrate the effectiveness of salt iodization in the control of endemic goiter. An evaluation done in 1979 in Guatemala, however, indicated that the prevalence of endemic goiter h ad increased at the level of the general population, rising from S.3% in 1965 to IO.S% in the school population in 1979. Together with the increase in goiter, a reduction in the urinary excretion of iodine was noted. Also, analyses of salt samples colle cted in the study communities showed that the salt did not contain iodine or the levels of iodine were low. ln many cases, the origin of the salt could not be determined. but when this was possible, it was found to have been imported from other countries in the Central American area. This situation has prompted authorities responsible for iodization control to renew their efforts to keep an effective program in operation. Guatemala's unfortunate experience demonstrates the need for a critical analysis o f iodization programs to obtain a clear definition of technical and administrative responsibilities and of authority. Chronic iodine deficiency and the resulting endemic goiter and cretinism will continue to be a public health problem in the affected are as unless the intake of iodine is increased. The case of Nicaragua illustrates the fact that when there is no intervention aimed at providing iodine to a deficient population, endemic goiter remains stable. Studies carried out in that country in 1966 an d 1976, before salt iodization was initiated, cited goiter prevalences of 32% and 33%, respectively, compared to the findings after four years of salt iodization, which showed that the overall prevalence of goiter decreased to 20%.
Table 3 depicts the results of studies in 16 countries of urinary excretion of iodine, together with studies on the prevalence of goiter. The higher prevalences of goiter are associated with lower urinary excretion of iodine. Bolivia, Ecuador, and Peru, along with Venezuela to a certain extent, continue to have high prevalences of endemic goiter. ln both the mountains and the jungle of these Andean countries, there is a shortage of iodized salt owing to problems of salt distribution, transportation, and marketing. This situation results in the populations' consuming salt that has either no iodine or is inadequately iodized. This is compatible with the high prevalences of goiter and with the low urinary excretion of iodine observed in these populations .
Only Nicaragua, Bolivia, and Ecuador currently have systems for, the epidemiological surveillance of endemic goiter. Of these, Nicaragua has had an operational system for seven years, whereas Bolivia and Ecuador are in the initial implementation phases ( see Table 4).
Most of the countries do not have recent information on the control of iodization; of those that do have such data, most reveal that iodization is deficient and poorly controlled. Usually the responsible staff have inadequate training or inappropriate fa cilities to perform the analyses.
Although dietary and environmental goitrogenic factors have been identified (3, 7), iodine deficiency still appears to be the most important factor in the persistence of endemic goiter in the Western Hemisphere. Once iodine deficiency has been corrected, we believe that every effort should be made to identify the areas and the ecological conditions in which the residual problem of goiter persists, such as in the Cauca Valley in Colombia and in the region of Lake Kivu in Africa (3,6). The need to impleme nt well-organized programs to ensure the eradication of iodine deficiency in the general population, including systems of evaluation and control, is a necessary step toward advancing our knowledge of the relative contribution of goitrogenic agents and of ways to control them.
In regard to the salt supply, it was determined that 11 of 18 countries were self -reliant and two depended totally on imports. The rest imported a certain amount of salt. lt. is also known that at borders between countries, there are infiltrations of no niodized salt prompted by differentials in the availability and price of salt. These facts stress the need to consider control mechanisms that ensure that all salt meets the iodization requirements in accordance with the legislation of the countries. Ex cluding compulsory iodization of salt for animal consumption gives rise to fraud and greatly complicates the processes aimed at ensuring an adequate intake of iodine by the population. lt. should also be kept in mind that the raising of domestic animals i n iodinedeficient areas is affected negatively by such deficiency. Thus, it is essential to include salt iodization for animal consumption within the programs for the prevention and control of endemic goiter and cretinism.
The cost of iodization varied greatly from one country to another. Cost is tied to the procedure used for fortification and to the production and marketing system used in each country. The cost of one kilogram of iodized salt to the general consumer ran ged between US$0.12 and USSO.30, with an average of US$0.20. Noniodized salt costs less and is frequently unsanitary. In some regions, the marketing of this type of salt constitutes a major problem; however, in these same countries alternatives do exist to ensure consumption of a product of good sanitary and nutritional quality. The key bottlenecks can be traced to salt distribution and marketing practices and to failure to use efficient and economical methods of iodization and control (19).
Potassium iodate is used in the salt iodization process except in Ecuador and Colombia where potassium iodide is employed. The methods of iodization used were the dry-mix, using a premix with an antihumectant and an antiagglomerant; the aspersion method, using an aqueous solution of an iodine compound alone or with other chemicals; and the drip method, using an aqueous solution of potassium iodate.
The levels of fortification ranged from 15 to 100 ppm iodine/salt in the 16 countries that have an iodization requirement. Both experience and theory, depending on the severity of the deficiency and on the level of salt intake, indicate that all these le vels are effective for the correction of iodine deficiency and are also innocuous.
The average consumption of salt per person per day in 14 countries ranged between five and 14 grams, with an average of 9.76 grams.
The average cost of salt iodization per person per year is on the order of US$0.015; even if all the costs involved in the production and marketing of iodized salt are included, as in the higher calculation for Nicaragua, the cost per person per year is l ess than US$.06. With the exception of Brazil, the cost of iodization is borne by the consumer. Actually, the cost of iodization is not a valid excuse for the irregularity of the process, especially since the consumer usually ends up paying for such cost s.
Numerous examples show that salt iodization is accepted when the measure brings economic advantage to the producer and to the salt dealer, and is rejected if the measure does not involve financial benefits. Thus, salt iodization is often an excuse to inc rease disproportionately the price of salt to the consumer. This results in the establishment of a black market of noniodized salt, which is further facilitated if salt for animal consumption is not iodized. Economic feasibility studies on production an d marketing cooperatives for iodized salt make it clear that, with increases in the price of salt that are almost imperceptible to the consumer, the cooperatives can enjoy substantial profits. These funds would enable them not only to defray all the cost s of the iodization process, but also to pay for the equipment and its installation and to achieve an income level that can promote their social development (20).
At the country level, it is sometimes difficult to obtain the foreign currency necessary to purchase potassium iodide or iodate and the other inputs required for the iodization process. The creation of a revolving subregional fund for such purposes may b e a viable mechanism.
Emphasis must be given to the need for honesty throughout the iodization process, since, given the shortcomings in control, large volumes of noniodized salt are sold, and the population not only pays for a benefit that it does not receive, but also suffer s the negative effects of iodine deficiency. To ensure that the population receives the desired benefit, it is first necessary to establish effective mechanisms for control and surveillance of the process (from the production of iodized salt to its consu mption).
Of the 16 countries studied, only one performs qualitative tests for the control of iodization and includes these tests at the consumer level. Four countries perform analyses as a company responsibility (see Table 6). Usually, control at the plants take s place only in large industries. It is possible to institutionalize this compulsory requirement throughout the industries in order to exercise control. In some countries, the salt industries are nationalized, which presupposes the faithful compliance w ith the letter of the law in terms of salt iodization, especially since many conceive salt as a food and as a social benefit. This premise is false in most cases, however, because, in reality, when one acts with a strictly commercial mentality, the margi n of net profit constitutes the major goal and the social benefits become secondary or nonexistent.
Procedures to effectively measure the social and economic cost of an iodine-deficient population, and its consequent diminished physical and mental capacity, are not being utilized. Furthermore, there have been few attempts to accurately measure the cost s of medical care for endemic goiter and cretinism and for the various associated thyroid pathologies. The possible impact of these factors on development has not yet been quantified. However, with the information that is available (albeit gross), it ca n be said that a country's investment in an efficient program of prevention and control of endemic goiter and cretinism can be highly profitable. The Latin American reality, with few exceptions, however, is that there is a lack of interest and support on the part of both governments and technical health groups. This disinterest is expressed in the delay between the approval of an iodization law and the implementation of a program whose effectiveness has long been proven (median of five years, Table I), and in poor operational standards. Basically, this unconcern is due to a lack of information on the part of the people, the governments, and technical groups about the magnitude and consequences of the problem and about the feasibility and characteristic s of available solutions.
As mentioned previously, the salt-producing communities can develop systems to derive economic and social benefits for themselves while simultaneously providing a social benefit to the community by iodizing the salt they produce and selling it at a reason able price. Community support for the program can only be obtained through organization and information dissemination. The technical and decision-making bodies need this support to resolve a problem that is a disgrace to our Hemisphere, especially since the technical solutions have been known for decades and their application has been feasible for several generations. A serious commitment must be made, at politic, technical, and comrnercial levels, to prevent and control iodine deficiency and endemic g oiter and cretinism in Latin America, by ensuring the effectiveness of salt iodization programs and also by considering the implementation of other needed measures.
Conclusions
Iodine deficiency and endemic goiter are still a problem in many of the countries of Latin America. ln Bolivia, Ecuador, and Peru, cretinism is a frequent syndrome associated with elevated prevalences of endemic goiter.
Although there are legal provisions for the iodization of salt, they are not implemented adequately.
The persistence of the problem seems to be due principally to a number of factors. There is no commitment at decision-making level's to assign priority to the eradication of iodine deficiency or endemic goiter and cretinism, and the amount of information on these problems is highly deficient. There is frequently noncompliance with iodization laws, and the legal provisions on iodination often do not include salt for animal consumption. A diversity of sources and production sites exists. There is also a lack of organization in the creation of socially, economically, and technically adequate systems of salt iodization. The supply of iodized salt in remote locations is minimal, and noniodized salt has infiltrated the markets. At present, there are few a dequate operational systems to control iodization, or to make iodized salt available at the market and consumer levels, even when the salt industry is nationalized. Systems of epidemiological surveillance are even less satisfactory.
Studies on the production and marketing of salt are not carried out adequately. This has an impact on the price of iodized salt, which, in turn, affects consumption and causes infiltration of lower-priced, noniodized salt. There is need for intersection al coordination to seek effective information for policy use, given the nature of the salt-mining industry and the aspects of production, transportation fortification, packing, distribution, and marketing. However, these coordination mechanisms are not f ormalized.
There has been no definition of the financial mechanisms required to maintain the programs; even when these are specified, they have not been fulfilled.
Most goiter control programs have serious shortcomings in their efforts to evaluate the progress of the program and its impact. Among the most significant difficulties are: poor definition of control methods and epidemiological surveillance; defective sa mpling in the prevalence studies; unspecified frequency for repeated evaluations; differing methods for the classification of goiter, both among countries and between periods of evaluation within the same country; - inadequate manpower training; and few r esources for carrying out control and evaluation measures.
Most countries fail to develop the educational component of these goiter prevention programs, both for the general population and for those involved in the production, control, and marketing of iodized salt. Professionals, health personnel, and others in relevant sectors also require additional education on this subject.
Recommendations
The Pan American Health Organization and the World Health Organization (PAHO/ WHO) encourage the Governments of Latin America:
(l) To regard the prevention of iodine deficiency and the control of endemic goiter and cretinism as a matter of high priority.
(2) To consider within the general health policies of the countries and within their health system infrastructure the implementation of programs aimed at the prevention of iodine deficiency and the control of endemic goiter and cretinism.
(3) To review laws and regulations with a view to ensuring that all salt is iodized.
(4) To promote and establish intersectoral and international mechanisms of cooperation and coordination for control of the distribution and marketing of salt.
(5) To implement existing iodization procedures including adequate financing systems for their control.
(6) To motivate and organize the small salt dealers to produce and iodize salt efficiently.
(7) To train the personnel responsible for the programs.
(8) To use the social communication media to educate the population on the problems of iodine deficiency, goiter, and cretinism and on the importance of consuming iodized salt.
ACKNOWLEDGMENTS
The authors wish to express their gratitude to the national authorities, to the companies and public and private corporations, and to the scientists and technicians in the countries who participated in the evaluation, for their valuable collaboration in b ringing this work to fruition, and to the staff and support personnel in the Country Representative Offices of the Pan American Sanitary Bureau in the participating countries and to the Institute of Nutrition of Central America and Panama (INCAP) for thei r efficient support. They also express appreciation for the effective and impartial assistance of the following persons: Dr. Victor Valverde, Dr. Jorge Tavera, Dr. Carlos Pérez, Dr. Luis Octavio Angel, Dr. Oscar Pineda, Miss Marta Yolanda Lara, Mrs. Soni a de Jiménez, Mrs. Beatriz de Rodríguez, Miss María Isabel Galvis, Mrs. Isolda Riveraiaínez, and Mrs. Anadina Ward.
Reprinted from "Towards the Eradication of Endemic Goiter, Cretinism, and Iodine Deficiency" with permission from Pan American Health Organization. This publication is available in full from the Pan American Health Organization, $10.- plus $6.- shipping and handling. To request a publications catalog, write to: Pan American Health Organization, Publications Program, 525 Twenty-third St., NW, Washington, DC 20037. Fax: 202/338-0869.
