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Endemic Goiter in Brazil |
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Endemic Goiter in Brazil |
Endemic goiter still constitutes a serious public health problem in Brazil as shown by two national student surveys over the last 30 years.
During the 1960s, the Ministry of Public Health developed a program for iodination of cooking salt; however, it did not produce practical results. Reasons for this failure were logistical. Potassium iodide was obtained only from external sources and was available to the salt industries at irregular intervals. Moreover, much of the salt consumed in the endemic areas was not processed and was thus not iodinated.
After 1974, salt iodination efforts became increasingly lax. This laxity can be attributed to the following factors: (1) the fragile economic structure of the salt manufacturing sector, which mainly consisted of small producers; (2) inadequacies in the e ducation, financial support, and control of the health authorities, as well as of the salt producers; and (3) the use of an unreliable iodinating system, including inadequate equipment at the production sites and refineries and untrained personnel.
Because of the enormous socioeconomic consequences of endemic goiter in Brazil, the Ministry of Health, in 1978, created a program to combat this problem. Responsibility for the effort was assigned to the Task Force for Specific Nutritional Deficiencies. It was only after the signing of Ministerial Regulation MS027, on March 2, 1982, however, that procedures and activities were formally established and a technical group for central coordination was formed.
Under the program, responsibility for implementing measures to eliminate endemic goiter rested with the Instituto Nacional de Alimentacao e Nutricao (INAN) and the Superintendencia de Campanhas de Saude Publica (SUCAM). The program's main prophylactic ac tion was the formulation of a subprogram of salt iodination for human and animal consumption, beginning in January 1983. A nurnber of research epidemiologists were enlisted to assist in the program's development
Epidemiological Studies on Endemic Goiter in Brazil
More than 40 years ago, Duarte Nunez (1) observed that military recruits exhibiting thyroid insufficiency were physically small in stature; thus, he advised that those with such symptoms or who suffered from goiter be declared unfit for military service. Pais de Olivera (2,3), in 1955, conducted a study of 20,000 adults of military age from 200 communities in the States of Parana, Santa Catarina, and Rio Grande do Sul, and found 25% had endemic goiter. Of these recruits, 50 to 80% were considered unfit to serve in the military.
In 1939, Dr. Lobo Leite (4,5) discerned an average goiter prevalence of 44% in Ouro Preto, Barbacena, Sabara, Congonhas, and Conselheiro Lafayete. He also identified the areas most affected with cretinism, deaf-mutism, and mental retardation. Other stud ies in Minas Gerais included those of Paula (l3) and Pinto Viegas (14), the latter reporting 2,52 cases of thyroid disease among 2,500 clinic registrants.
Between 1940 and 1947, Dr. Arruda Sampaio (6-10) studied 22,000 schoolchildren and adolescents in São Paulo. He found a goiter prevalence of 5 to 10% along the coast and 70 to 90% in the interior. The São Paulo region, including Campinas, Botucatu, Piram boia, and Anhembi, was also scrutinized in 1943 by Drs. A. Lyra, A. Melo, and Albuquerque (11). An examination of 850 boys and 712 girls revealed a goiter prevalence of 35.8% and 44.8%, respectively. A survey of 3,030 boys in the City of Campinas in 194 4 by Melo and Albuquerque (l2) disclosed a goiter prevalence of 70.6%. Dr. Peregrino (15), from his studies of endemic goiter in the interior of Rio de Janeiro, made the remarkable statement that all the inhabitants had this disease and persons who did no t have goiter were considered abnormal. The prevalence found in those areas was 38.7% of those ex-amined. In 1946, Lowenstein (17) described malnutrition and endemic goiter in 84 families in the community of Canchera de Beltena, in Tapajos. In 1952, Silv a and Borges (]8) studied 6,803 schoolchildren aged seven to 21 in Goias and Mato Grosso, and found goiter endemic in Cuiaba (72%), Goiania (66.6%), and Goias (81%). The prevalence of goiter was greater in rural zones, in public schools, and in the lower socioeconomic and cultural groups. In 1958, Pinotti (l6) studied five regions of the country and estimated that of the 62,100,000 inhabitants of Brazil, 11,640,000 had goiter, representing a prevalence of approximately 18.7%.
Studies of the prevalence of goiter were made at the national level in 1955 and again in 1975. Overall, a decrease of only 6.5% was noted in a 2O-year period, despite an enormous reduction in goiter of grade 3. The 1975 study consisted of 421,756 student s (203,251 boys and 218,505 girls), aged seven to 14 years, who had goiter prevalences of 11.7% and 16.3%, respectively (see Table 1).
Table 1. Goiter among schoolchildren, 1975. ------------------------------------------- Total Percentage State examined with goiter ------------------------------------------- Rondonia 2,019 31,3 Acre 1,840 15,4 Amazonas 8,680 12,0 Roraima 1,106 1,3 Para 14,536 12,3 Amapa 3,725 4,9 Maranhao 13,150 25,7 Piaui 9,216 3,1 Ceara 19,547 6,3 R. G. do Norte 12,400 0,7 Paraiba 11,571 1,0 Pernambuco 17,331 10,0 Alagoas 10,650 9,6 Sergipe 6,084 1,5 Bahia 26,239 33,3 Minas Gerais 55,527 28,6 E. Santo 10,525 12,4 R. de Janeiro 27,070 14,5 São Paulo 51,115 18,7 Parana 31,587 1,5 Sta. Catarina 16,054 1,3 R. G. do Sul 30,592 7,2 Mato Grosso l5,l52 16,3 Goias 17,243 13,8 D. Federal 8,793 3,0 ------------------------------------- Total 421,752 100,0
Legislation on the lodization of Salt, and Prevention and Control of Endemic Goiter
Legislation dealing with the iodization of salt includes the following:
Structure of Salt Production in Brazil
Before 1976, the extraction and processing of salt in Brazil was based on marine salt. Today marine salt accounts for ali salt for human and animal consumption. Exploration for land salt began in the States of Alagoas and Bahia in 1977, with ali of its production designated for the chemical industries.
As the salt plants became modernized over the past few years, a certain equilibrium has been achieved between production and demand. Ninety percent of the demand for salt was for Brazil's own internal consumption. Of this amount, the chemical industry r equired 48.7%; human consumption, 11.3%; and agricultural consumption, 24.7%. In 1982 the national production of marine salt reached 2,887,803 tons, 84.8% of which carne from the State of Rio Grande de Norte. Other major producers were Rio de Janeiro (33 2,630 tons), Ceara (64,063), Maranhao (25,827), Piaui (l I,615), and Sergipe (2,316). Only 214 of 577 salt producers surveyed were active in 1981. The total area of crystallization was approximately 24 million square meters.
Nationally, 50% of the salt is distributed by sea and 40% by rail. The regional distribution of processei salt is handled almost completely by railroad. Approximately 73 % of the crude marine salt extracted is improved through milling and refining indus tries. The production of milled and refined salt in 1983 reached 2,100,000 tons, 70% milled and the rest refined. The technical specifications for sodium chloride assure its quality is equal to that of ali internationally competitive sources.
Program to Combat Endemic Goiter in Brazil
In February 1982, the Ministry of Health created a combined technical group to coordinate the program to combat endemic goiter. Later, in November 1982, an INAN regulation appointed the group members and established their responsibilities. In 1983, this technical group developed a proposed law dealing with the prevention of endemic goiter and submitted it to the Ministries of Health, Agriculture, Industry, and Commerce for the approval of the President of the Republic. The program's stated objective was to reduce the prevalence of endemic goiter to acceptable public health levels and to eliminate endemic cretinism from the country.
The effort calls for the resumption of salt iodination programs at the national level. Examples of its implementation to date include the following: (l) assuring that iodine in the form of potassium iodate (KlO3) is acquired for distribution to all salt producers; (2) registering all salt producers; (3) developing dosification equipment that has been simplified for iodate for distribution to salt producers; (4) increasing the iodine content of salt from 10 mg/kg to 15 to 30 mg/kg; (5) proposing modificat ions in the present legislation dealing with salt iodization in Brazil and the prevention of endemic goiter; (6) providing technical assistance to salt producers and exercising systemic control of iodization; and (7) establishing planning and operational mechanisms for surveillance and for funding of salt iodization at the production and marketing levels.
Another objective is to define goals for program improvement, including: (1) implementation of studies and periodic epidemiologic research in areas with low and high goiter prevalence, and correlation of the data obtained with iodized salt consumption to aid in recommending specific treatments; (2) evaluation of the technical and scientific aspects of the program, aided by specialists; and (3) promotion of education and publicity campaigns. Subprogram of Iodization of Salt in Brazil
The Ministry of Health began implementation of the salt iodization subprogram in January 1983. Initially, the program got underway in the principal salt-producing States, Rio Grande do Norte, Rio de Janeiro, Rio Grande do Sul, São Paulo, Ceara, and Parana . Together, these States produce about 90% of Brazil's refined and milled salt. The program gradually will be expanded to encompass ali of the states that produce salt. This expansion will include 172 refineries and milling operations in 50 communities .
As it is common practice in rural areas to use agricultural sait for human consumption, the Ministry of Health's concern over assuring iodization of salt for agriculture is justifiable. Generally, these rural areas coincide with those exhibiting the grea test prevalence of goiter. Also, it is impossible to distinguish between the consumers of the final product-agricuitural users or the rural population. For this reason, the new law proposed to the National Congress will refiect a more clearly stated gov ernment position. The proposed legislation requires a practical solution to the problem of salt iodization.
The technical group of the Program to Combat Endemic Goiter has been charged with the following responsibilities: (l) to establish, with the participation of the regional directors of SUCAM, basic norms and standards specific to the distribution of equipm ent and of iodate; (2) to provide technical education and other assistance to salt producers; (3) to propose modifications in the legislation on salt iodization; (4) to promote acquisition of iodate and supplements by the state; (5) to establish a model o f dosification for distribution to the industries; (6) to establish permanent mechanisms of financing and standards of purity for the iodate to be purchased; (7) to train the personnel responsible for carrying out the activities of the project; (8) to mak e yearly proposals of goals and a detailed work schedule, to be developed jointly with SUCAM and INAN; (9) to establish medium- and long-term goals for improvement of the program; (10) to collaborate with the regional directors of SUCAM in establishing th e structure and technical support for carrying out these activities; and (l 1) to coordinate and evaluate the iodization project.
The responsibilities of the SUCAM regional directors include the following: (l) to establish baseline data, by means of a questionnaire, on the status of salt production; (2) to promote the allocation of specific personnel in sufficient numbers to handle the prescribed activities, including a coordinator responsible to the technical groups; (3) to aid in the acquisition and distribution of equipment for dosification of iodate, especially to those industries most in need; (4) to encourage and reactivate la boratories dedicated to the control of salt iodization, including provision of materiais and chemical reagents necessary for analysis of iodine levels; (5) to educate the salt industries on proper procedures of salt iodization and to collect samples for a nalysis; (6) to educate the producers on the importance of iodization; (7) to make weekly visits, through an agent designated for this purpose, to the industries to collect salt samples and to obtain the results of analyses of collected samples; (8) to ha ve another specifically-designated agent, using portable laboratory equipment, make visits to industries at least monthly, without prior announcernent, to conduct on-site analyses of iodine content, as well as to inspect the equipment, the iodate stock, e tc.; and (9) to propose needed changes or modifications in the project's operation.
The responsibilities of the salt producers include the following: (l) to conscientiously follow salt iodization procedures; (2) to permit free access of the SUCAM agents to producers' installations; (3) to be receptive to the educational and control effor ts of the SUCAM agents; (4) to faithfully follow a daily calendar of salt collection for analysis, with each machine and each shift providing two samples daily; and (5) to designate someone to be responsible for receiving the potassium iodide and dosifica tion equipment.
Results Obtained in the Subproject (January to September 1983)
All 172 refining and milling industries surveyed are being offered technical assistance. A dosification model was developed for the subprogram, and 176 of the 200 units needed have already been put into operation in salt plants. A total of 43 SUCAM empl oyees, including sanitarians, inspectors, laboratory technicians, and public health agents, have been trained to carry out, assist, and control the iodization of salt at the state level. This allows a ratio of one trained person per four salt plants assi sted.
Between January and September 1983, 22 support laboratories, both permanent and portable, were installed to analyze and control the dosage of iodine in the salt. By the end of 1983, 11 additional laboratories will be operational, bringing the total to 33 units in 15 states. From January to September 1983, 55.65 kg of potassium iodate were acquired, of which 34.4 kg were distributed to the plants. The actual amount used to produce iodized salt was owever. The potassium iodate used in the program is pro duced in Brazil, but the iodine necessary to make the iodate must be imported.
A 1975 survey of Brazilian schoolchildren found an overall goiter prevalence of 14.7%, with the largest concentration in the inland areas. States with prevalences greater than 20% included Bahia, Rondonia, Maranhao, and Minas Gerais. Laws and programs f or salt iodization have existed for many years, but are generally ineffective. Recently, a massive program of salt iodization was initiated under the direction of a national goiter program. The program involves the distribution of potassium iodate to sa lt producers, educating them in its use, and providing surveillance of its effects.
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(2) Paes de Oliveira, P., et al Areh Brasil Med 45:371, 1955.
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(5) Lobo, Leite, A. Mem Inst Oswaldo Cruz 38.1.,1943.
(6) Arruda Sampaio, A. Pediat Prat (S. Paulo) 11-215, 1940.
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(16) Pinotti, M. Arqu Brazil Med 19:7233,1958.
(17) Lowenstein, F. W. Amer J Clin Nutr 7:331-339, 1959.
(18) Silva, W., and P. Borges. Trab Inst NutUniv Brasil 5: 19, 1952.
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.