Prevalence Of Endemic Goiter Research Articles

Iodine in the environment and endemic goitre in Sri Lanka

Abstract The prevalence of endemic goitre is extremely high in certain parts of Sri Lanka where rates as high as 44% have been observed. With nearly 10 million people at risk the aetiology of endemic goitre in Sri Lanka needs to be clearly ascertained. The endemic goitre belt of Sri Lanka coincides with the wet climatic zone, indicating an apparent relationship of iodine geochemistry with climatic factors. However, the fact that there is a correlation of only −0.64 between the iodine content and the prevalence of goitre suggests the existence of other factors such as humic substances in the soil, clay minerals and soil pH that exert an influence on the bioavailability of iodine. Iodization of salt used in food is the most convenient method of goitre prevention.

Endemic goiter and thyroid function in central-southern Sardinia. Report on an extensive epidemiological survey.

Although the existence of endemic goiter and cretinism in Sardinia is known since to ancient time, scanty information collected according to WHO criteria is available. In the present paper the results of an extensive epidemiological survey carried out in juvenile population living in some rural and/or hilly villages in the provinces of Nuoro and Oristano in Central-Southern Sardinia and in urban area of Cagliari, are reported. In the majority of the villages the mean urinary iodine excretion was lower than 60 micrograms/L; the goiter prevalence ranged between 39% and 61% in the district of Nuoro and between 21% and 56% in the district of Oristano. In the control area the urinary iodine excretion was 105 micrograms/L with a goiter prevalence of 12%. Goiter prevalence was not always inversely related to urinary iodine excretion. No relevant thyroid function alterations were found. 1) in extraurban areas of Central-Southern Sardinia mild to moderate iodine deficiency and endemic goiter are still a widespread problems; 2) also in urban area endemic goiter prevalence is still higher than 10%; 3) extemporary urinary samples are inadequate for assessing the severity of goiter endemia in mild to moderate iodine deficiency; 4) in mildly affected districts palpation is inaccurate for assessing the prevalence of goiter; 5) no relevant alterations of thyroid function were documented in juvenile population.

Intellectual and motor functions in school children from severely iodine deficient region in Sikkim.

High prevalence of endemic goitre (54%) and endemic cretinism (3.5%) exist in Sikkim. The level of intellectual functioning and motor performance were assessed in 90 school children in the age group of 10 to 12 years selected randomly from four severely iodine-deficient villages. Bender Visual Motor Gestalt Test, Binet-Kamat Test for mental ability and Raven's Coloured Progressive Matrices were the tests used. The results show an impairment in intellectual and other neuropsychological functions in a high percentage of the children. Visuomotor coordination was poor in 62 (69%). Binet-Kamat test results showed that 19 (21%) children were intellectually subnormal (IQ < 70). Majority of the children (> 80%) had significant impairment in language, meaningful memory, non-meaningful memory, conceptual thinking, numerical reasoning and motor skills. The children did better on non-verbal reasoning and social intelligence. Goitre was detected in 82 (91.1%). Urine samples for iodine estimations was collected from every second child examined. The mean urinary iodine concentration was 4.23 micrograms/dl (SD 2.16). Urinary iodine concentration was less than 2 micro gm/dl in 26.1% (11 children) and less than 5 micro gm/dl in 84.8% (39 children) indicating severe iodine deficiency. The test results show impairment of psychomotor development in children born and brought up in iodine-deficient environment.

Interobserver Variation in the Assessment of Thyroid Enlargement: A Pitfall in Surveys of the Prevalence of Endemic Goitre

An important concern in surveys of the prevalence of endemic goitre is the possibility of inaccuracy that can occur when estimating thyroid enlargement by clinical examination. We report here the results of a study from central Africa that demonstrated the importance of interobserver variation in the assessment of goitre size among experts and participants attending an international training course on iodine deficiency disorders (IDD). Agreement among raters estimated by calculation of the kappa statistic was poor on average when the five-stage goitre classification recommended by WHO was used. As expected, agreement on a single category was slightly better, especially when the category of interest was visible goitre. Our results suggest that palpation alone is not a reliable method for assessing the severity of IDD endemia. Other sources of inaccuracies are discussed and recommendations are made for better data collection on IDD in Africa and other regions.

Iodide Concentrations in Saudi Waters: A Cause for Concern

Samples of tap water and drinking mineral water from different regions of Saudi Arabia were analyzed for iodide content. Low iodide concentrations were found in all samples. This finding may reflect an overall low iodide content in the soil and consequently also in locally grown food, which could predispose to endemic goiter. In the absence of data on the prevalence of endemic goiter, we recommend the routine use of iodized salt in Saudi Arabia.

Anomalously low endemic goiter prevalence among Efe pygmies.

The existence of endemic goiter, caused by iodine deficiency and the presence of a dietary goitrogen, has been noted in eastern Zaire by a number of authors (De Visscher et al.: Journal of Clinical Endocrinology and Metabolism 21:175-188, 1961; Delange et al.: Journal of Clinical Endocrinology and Metabolism 34:1059, 1972). In the Ituri Forest of Huate-Zaire, two distinct populations, the Efe (pygmy) and Lese (Bantu), live in association with each other and have similar diets. The goiter survey reported here documents differences in goiter prevalence and severity between the nomadic pygmy and village-living Bantu populations. While the Efe have an overall goiter prevalence of 9.4%, the Lese have a goiter prevalence of 42.9%. Furthermore, Efe women living in Lese villages and subsisting on a Lese diet have a prevalence of goiter similar to that of forest-living Efe women. Village-living individuals born of Efe mothers and Lese fathers have a prevalence of goiter greater than that of pure Efe but less than that of Lese. While our data cannot exclude dietary explanations for the difference in goiter prevalence between the Efe and Lese, they do support the hypothesis that the Efe possess an adaptation to an iodine-deficient environment that does not result in the development of goiters.

The prevalence of endemic goitre among a rural population in some parts of Donga-Mantung division, Cameroon

Fifteen clusters of houses in eight villages were chosen, and 20 families were randomly selected in each of the clusters from a list made during a medical census: 1,086 subjects were examined. The prevalence of goitre was found to be 18% for the whole population: 15% for the males and 21% for the famales. The staple food is cassava which is eaten without soaking. Although several factors may contribute to causing goitres, iodine supplementation is recommended as the best preventive method available.

Prevalence of goitre and hypothyroidism in Southern Tanzania: effect of iodised oil on thyroid hormone deficiency.

In the Southern Highlands of Tanzania the prevalence of endemic goitre due to iodine deficiency is in the range of 90% and hypothyroidism in the range of 50% of schoolchildren. The present study confirms these data and documents the beneficial effect of Lipiodol injections on thyroid function in children around the age of puberty compared with untreated children from the same villages. On the other hand, a decrease in the prevalence of goitre could not be shown. A beneficial effect is shown for infants of mothers who received iodine during pregnancy. It seems that this form of supplementation is sufficient for breast fed children for more than three years, even when a second child has been delivered in the meantime. In contrast, older siblings of these babies may become hypothyroid when breast feeding is stopped. The determination of thyroid autoantibodies in iodine treated and untreated children and in young adults showed no increasing prevalence of positive findings thus excluding iodine induced chronic thyroiditis at least in the young target population.

THE GEOGRAPHICAL DISTRIBUTION OF THYROTOXICOSIS IN ENGLAND ACCORDING TO THE PRESENCE OR ABSENCE OF TSH‐RECEPTOR ANTIBODIES

In a prospective study of the incidence of thyrotoxicosis sera from 216 thyrotoxic patients in seven English towns were assayed for TSH-receptor antibodies. The incidence of antibody negative thyrotoxicosis correlated closely with the previous prevalence of endemic goitre in the towns (r = 0.9) indicating a high current incidence of toxic nodular goitre in previously goitrous towns. Antibody positive thyrotoxicosis, an indicator of Graves' disease, showed no correlation with goitre although there was statistically significant geographical variation in incidence. The percentage of all thyrotoxic patients who were antibody positive varied between towns, from 35% to 92%.

Pilot study to detect neurologic disease in Ecuador among a population with a high prevalence of endemic goiter.

A census, uniform screening questionnaire, and simple screening neurologic examination were administered in a door-to-door survey to residents of Quiroga, Ecuador, a rural community in the Andes Mountains. The screening procedures had been pretested to assure a high level of sensitivity for detecting children and adults with major neurologic disease. A total of 1,113 participated in the study. Of these, 399 had responses or findings suggesting the presence of neurologic disease. These individuals were then examined by a neurologist, who used fixed diagnostic criteria. The prevalence ratios (per 1,000) for the most common neurologic conditions identified in this survey are: recurrent/persistent severe headache = 68.3, and epilepsy = 17.1.

CURRENT INCIDENCE OF THYROTOXICOSIS AND PAST PREVALENCE OF GOITRE IN 12 BRITISH TOWNS

The incidence of thyrotoxicosis was determined in a collaborative study in 12 towns in England and Wales. Cases were ascertained prospectively through biochemistry laboratories carrying out routine thyroid function tests. The annual incidence varied from 9·7 to 49·2 per 100 000. Reassay of sera at a reference laboratory showed that this variation did not result from inter-laboratory differences in the techniques for measuring thyroid function. The incidence of thyrotoxicosis was strongly correlated with the previous prevalence of endemic goitre in the towns. Current high dietary intakes of iodine—largely the result of milk contamination—may cause toxic nodular goitre in people made susceptible by a lack of iodine early in life. They may also contribute to the occurrence of Graves' disease.

Mortality from thyrotoxicosis in England and Wales and its association with the previous prevalence of endemic goitre.

The distribution of mortality from thyrotoxicosis among women in England and Wales during 1968-78 correlates with the previous prevalence of endemic goitre. Mortality from the disease rose to a peak in the decade 1931-40 and then declined. This peak affected all age groups and can be attributed to the high fatality from surgery before the introduction of preoperative iodine to prevent thyroid crisis. An apparent cohort effect, whereby cohorts born from 1871 to 1886 experienced the highest mortality, may be explained by generations with a high prevalence of endemic goitre becoming exposed to increasing dietary iodine intake in later life.

Antithyroid compound(s) produced by Escherichia coli: preliminary report.

ABSTRACT This series of experimental studies was prompted by several epidemiological field studies of endemic goiter which demonstrated a relationship between bacterial pollution of drinking water and the prevalence of endemic goiter. An in vivo assay for antithyroid activity in the rat was developed. Antithyroid activity was demonstrated in cell-free, lyophilized, broth cultures of four species of organisms. The most consistent producer of antithyroid activity was E. coli and the material was partially purified by ultrafiltration. Dose response studies demonstrated antithyroid activity with known goitrogens and a satisfactory dose response was obtained from various fractions following ultrafiltration. However, based on estimated molecular weights of filtrates, antithyroid activity varied between batches but it was consistently present. The significance of this research is briefly discussed and further experimental work towards purification of the compound and demonstration of its mechanism of activity in...

Endemic goiter and endemic cretinism in the Andean region.

Analysis of iodide deficiency, thyroid function, altitude, neural and motor dysfunction and a variety of social and economic variables to ascertain the prevalence of endemic goiter in eight rural Andean villages showed that as many as 54 per cent of the population in certain villages had goiter, and neural and motor abnormalities characteristic of cretinism were present in up to 10 per cent of the population. All villages with goiter had severe iodine deficiency. Intercurrent unidentified socioeconomic and biologic factors in the community may have modified the severity of the endemic. High altitude seemed to depress goiter formation. With increasing severity of the endemic, there was a rising prevalence of nodular goiter, and an increase in goiter in children, in goiter in men as compared to women and in the average size of the glands. Endemic cretinism, deaf-mutism and motor abnormalities were highly correlated with the severest intensity of endemic goiter. The cretins studied did not appear to be hypothyroid.

ENDEMIC GOITRE AND IODINE MALNUTRITION IN IRAQ.

Abstract : Clinical studies of goitre in northern Iraq reveal a high prevalence of endemic goitre. Studies of urinary iodine levels in adolescent girls indicate that the main cause of the endemic is iodine malnutrition. The iodine content of water from the Tigris in the affected areas is low. (Author)