1. Observations have been quoted which mention the existence of goiter in remote inland areas of Malaya. 2. 39.5% of 618 Malays and 40.8% of 710 aborigines from inland areas were found on examination to have visible thyroid glands. A high incidence of thyroid enlargement was found in almost all areas where these observations were made, on a wide range of Geological Formations. 3. In the seaside populations studied, the low incidence of ‘visible’ thyroid glands (2/184) is typical of that of other ‘goiter free’ areas. 4. Iodine estimations have been carried out on seven water samples from rivers draining inland areas where thyroid data have been collected, and gave values of 0.2 to 0.6 parts of iodine per thousand million. The development of goiter is to be expected when the iodine content is so low. 5. High calcium content of waters cannot be important in causing goiter in Malaya. 6. The availability of dried seafoods is thought to be an important factor in goiter prevention in Malaya. Four dried marine foods contained 360 to 1,340 parts of iodine per thousand million.
A comparative epidemiological and anthropometric survey was conducted among Ibans, the largest indigenous ethnic group in Sarawak, in three regions where the endemicity of goitre exhibited marked differences , to assess the effect of endemic goitre on somatic growth. In the Ai river region the prevalence of goitre was 99.5%; 35% having grade 3 goitres, 55% grade 2 goitres and 9.5% grade 1 goitres. At Rubu the prevalence of endemic goitre was 74%; 3% having grade 3 goitre, 16% grade 2 goitre and 55% grade 1 goitre. In the Bajong region relatively few people were detected with goitre and most of these had migrated from other regions. Neurological cretinism was estimated at 3.6% in the severely goitrous Ai river population but was not detected in the other regions. Anthropometric data obtained from the three adult populations did not reveal any statistically significant differences in the following parameters: weight, height, weight/height ratio, height/sitting height ratios, head circumference, scapular skinfold thickness and left mid arm muscle circumference. The haemoglobin, serum total protein and serum albumin concentrations were similar in the three populations. It is concluded that endemic goitre occurs with a frequency of close to 100% in certain Iban populations which represents one of the highest incidences of endemic goitre in the world. Neurological cretinism is common in this population. Our observations suggest that body proportions and somatic growth do not vary among similar ethnic populations exhibiting greatly different endemicity of goitre. Although no iodine balance studies were performed, assessment of diets suggested that iodine deficiency is a significant contributory factor in the development of endemic goitre in Sarawak. Urgent attention to iodine supplementation is indicated to prevent the development of endemic goitre and neurological cretinism.
Eight longhouses were selected randomly for a goitre survey in the Entabai area of the Sixth Division, Sarawak. 645 subjects were examined and a goitre prevalence of 46.4% (15 years and above) was found. The females had a higher rate of 69.5% as compared with their male counterparts with 24.4%. Below the age of 15 years, prevalence was low and there was not much difference between the two sexes. After the age of 15 years, the prevalence among the females
increased from 40% to almost 80% by the age of 25 years. The males, on the other hand, showed a decrease in prevalence after the age of 15 years and levelled off at about 30%. The females also had much larger goitres than males. About 43% of the households surveyed consumed iodised salt but the rates tend to fluctuate according to supplies. There was however no direct correlation between goitre prevalence and consumption of iodised salt.
A large-scale study was undertaken in the state of Kelantan, to determine the prevalence of goitre. A total of 2,450 subjects above the age of 15 years were selected from 31 localities in the state and examination for goitre was done using the technique of Perez. The state was divided into 3 areas--coastal area (area 1), inland area (area 2) and the area in between the coast and the inland area (area 3). The overall prevalence of goitre was 36.8% and the prevalence in areas 1, 2 and 3 were 23.0%, 35.9% and 44.9% respectively and ranged from 6.9% in a locality in area 1 to 59.7% in a locality in area 3. In all areas, the prevalence was higher in females than in males. The prevalence of grades I, II and III goitres were 21.5%, 1.0% and 0.5% respectively in area 1, 33.6%, 1.5% and 0.7% respectively in area 2 and 41.7%, 2.2% and 1.0% respectively in area 3. Amongst age groups, goitre prevalence was highest in the 36 to 45 years age group in area 1 (33.9%), in the 15 to 25 years age group in area 2 (39.6%) and in the 26 to 35 years age group in area 3 (54.3%). In all the areas, goitre prevalence was lowest in the above 56 years age group. We concluded that the prevalence of goitre was high in Kelantan and there were regional differences in the prevalence rate within the state.
The prevalence of goitre was investigated in a sample from six longhouses and five primary schools located at varying degrees of remoteness along the Tinjar river, Sarawak. Together with this, a survey was made on the type of salt used by the households. The main ethnic groups in these communities were the Kenyah/Kayan and the Iban. The overall prevalence of palpable goitre detected from the age group 5-14 years were 71.7 percent and 77.0 percent for males and females respectively and 77.7 percent for females aged 15 years and above. The prevalence for both Iban and Kenyah/Kayan of either sex and for all age groups varied from 63.4 percent to 80.4 percent. The prevalence at each location did not differ significantly. On questioning 126 households, only 9 (7.1 percent) used iodized salt whilst 74 (58.7 percent) households used only uniodized coarse salt and 7 (5.6 percent) used only uniodized fine salt. The remaining 36 (28.6 percent) households used both fine and coarse uniodized salt. Undoubtedly at this point in time legislation on "table" salt iodization must be interpreted to mean not only the iodization of fine table salt, but in the case of the rural longhouse communities as are found in the Tinjar area, the iodization of coarse salt as well.
A significant difference in the levels of thyroxine (T4), thyroid stimulating hormone (TSH) and thyroid volume among settlements at various selected Orang Asli locations is reported. The levels improved according to the level of socio-economic development. No significant difference was found in mental performance by location.
Four areas of differing remoteness were studied to determine the prevalence of goitre in the Keningau Division of Sabah. These areas were Keningau town, the Biah Resettlement Scheme, the Dalit subdistrict and the Pagalunggan subdistrict. The predominant ethnic group in these areas is the Murut. The overall endemicity of goitre for the study population was 76.5% for females aged 15 years and above. There was a significant correlation between the incidence of goitre and the remoteness of an area. The Dalit subdistrict has the highest incidence of goitre (82.6%) followed by the Pagalunggan subdistrict (77.8%), the majority of these goitre cases being classified as grade 2 (visible goitres). These were the two most remote areas in the study. In contrast, Keningau town, the least remote area has the lowest incidence of goitre (62.5%) with most of the goitres being relatively small. With regards to salt usage in the Dalit subdistrict, only 3.0% used iodised salt; 28.0% used fine salt; 3.6% used coarse salt and 65.5% used both fine and coarse salt. In the Pagalunggan subdistrict, all females used uniodised salt with 17.6% using fine salt, 20% using coarse salt and the remainder using both fine and coarse salt. As yet, there is no legislation for the iodisation of salt in Sabah. It is clear that all types of salt need to be iodised and adequately distributed to deprived areas, particularly inland areas.
Endemic goitre is a major concern in many parts of the world, including Southeast Asia. Goitrous thyroid lesion is postulated as a precursor lesion to thyroid cancer (TC). This paper reviews the prevalence rates and characteristics of TC among cases of goitrous thyroid-swelling in different parts of Malaysia and Myanmar. Recorded data from hospital-based retrospective studies of thyroid cases, whose study periods ranged from three to 11 years, were analysed. These included research findings from the author's publications as well as other published review articles of retrospective analyses. The incidence of TC varies among gender, age, race/ethnicity and histological type. There appears to be a higher rate of occurrence among females aged 21-60 years. Papillary thyroid carcinoma is the more common histological type compared to follicular cancer. This review also presents a descriptive analysis and discussion on studies conducted in other countries. Further exploration is warranted in order to uncover the possible risk factors for the rising incidence of TC.
The prevalence of goitre was determined in several communities in rural parts of Pahang. Urine specimens were collected randomly among the participants. Drinking water from various sources such as river and spring, and water from gravity feed systems was also collected to determine the iodine content by using the ashing method. The results were compared to that of Kuala Lumpur City. lt was found that the prevalence of goitre in rural areas was between 20 and 70% depending on village, ethnic group, age and gender. The interior parts of the jungle where Aborigines lived was moderately endemic with goitre prevalence of goitre more than 20% and urinary iodine content 2.0-5.0 μg I/dl). A nearby Malay traditional village which was studied had mild endemia (prevalence 10-30% and urinary iodine content 5.0-10.0 μg I/dl) while a Felda Malay resettlement scheme and Kuala Lumpur City did not have endemic goitre. Endemic goitre in rural areas was associated with low iodine content in drinking water. Even though Kuala Lumpur had low iodine content in its drinking water there was no endemic goitre, indicating that other factors were more important.
In a survey of 974 villagers (408 males, 566 females; ages = 11-82 years) of the Ai (n = 496; 212 males, 284 females) and Lemanak (n = 478; 196 males, 282 females) rivers in the district of Lubuk Antu in Sarawak's Sri Aman Division during July 1993, goiter was found in 31.8% of the subjects. The goiter prevalence was higher in the more interior Ai river area than in the Lemanak river area (36.9% vs 26.5%). In females aged 15 years and above, the goiter prevalence was 75.4% and 49.1%, respectively, in the Ai and Lemanak river areas. The difference in goiter prevalence between the two areas was related to the degree of iodine deficiency in the two areas. The median urinary iodine excretion in the Ai river villagers was 22.1 micrograms/l compared to 72.9 micrograms/l in the Lemanak river villagers (p < 0.0001). Goitrous subjects tended to have lower urinary iodine concentration than non-goitrous subjects. In the males, smoking of tobacco was associated with a two-fold increase in goiter frequency. Despite on-going distribution of iodized salt by the medical and health services in the State, only 23% of the 135 salt samples obtained from the households in the areas contained detectable iodine.
An iodinator was fitted to the existing gravity-fed water-supply of a remote village in Sarawak, Malaysia, where goitre was endemic. Within nine months, the prevalence of goitre had been reduced from 61% to 30%, with 79% of goitres showing visible reduction in size. All subjects were clinically euthyroid before and nine months after the start of iodination, although pre-treatment serum thyroid-stimulating hormone (TSH) concentrations varied from normal up to 24 mU/l. Before treatment basal serum triiodothyronine (T3) and thyroxine (T4) concentrations were typical of endemic goitre with a low mean serum T4 (80 +/- 30 [SD] nmol/l) and a slightly raised mean serum T3 (2.3 +/- 0.7 nmol/l). After iodination, circulating TSH concentration was generally undetectable (less than 0.1 mU/l), mean T3 concentration was unchanged, but the mean T4 rose significantly to 109 +/- 41 nmol/l (p less than 0.01). Urinary iodine concentrations fluctuated; this largely reflected intermittent blockage of the iodinator, but concentrations became consistent with a return to the iodine-replete state. There was no evidence of the Jod Basedow effect in the group studied. Iodinated water was more convenient to distribute than iodised salt and is less likely to cause Jod Basedow phenomenon than are injections of iodised oil. Moreover, iodination of water is effective in killing most microorganisms and this additional benefit could contribute significantly to village health.
A simple water iodizing system, which incorporates the Venturi principle in combination with the controlled release mechanism of a silicone-sodium iodide elastomer, for the iodization of rural piped-water supply in the control of endemic iodine deficiency has been developed and its effectiveness evaluated in three Iban longhouse villages in the iodine-deficient district of Lubok Antu, Sarawak. Urines were collected for iodine assays from women aged 15-40 years before and at 6 and 12 months after the connection of the iodinating device; goiter assessment was performed on the women at the start and end of the 1-year study. Water samples were collected for iodine assays at 2-weekly intervals. In all three villages, significant and sustained increases in median urinary iodine excretions, reaching levels recommended for an iodine-sufficient population, were observed; goitre prevalences were reduced in all the villages (by 22.6% to 35.8%). The iodine levels in the water ranged from 34 micrograms/l to 212 micrograms/L. In the control village, median urinary iodine excretions remained essentially unchanged but a small increase in goiter prevalence was observed. The iodized water was well received by the villagers and no adverse effects of water iodization were observed. The system functioned unattended throughout the one year period. The cost of providing supplemental iodine via the iodizing device is approximately 60 cents (U.S.) per family per year which is affordable by either the Government or the villagers. It is concluded that the iodizing system offers a new cost-effective strategy for the control of endemic iodine deficiency in Sarawak and may have applications in other areas with similar water sources.
A study to determine the prevalence of goitre and abnormal thyroid status during pregnancy in Malaysian women was conducted. Two hundred and three women (Malay = 85, Chinese = 47 and Indian = 71) in the third trimester and with no known thyroid disease were studied. There was a marked racial disparity in the prevalence of goitre: Indian 61%, Malay 28% and Chinese 29% (p = 0.001). The serum thyrotropic hormone (TSH) was significantly higher in Indians (median: 1.36 uIU/ml) compared to Malays (1.14 uIU/ml, p = 0.009). The serum albumin was also significantly lower in Indians (mean +/- sd; 36.12 +/- 3.9 mmol/l) compared to Malays (39.3 +/- 4.8 mmol/l) or Chinese (39.1 +/- 5.2) (p < 0.001). Thyroid antibody was detected in 14.6% of these women with no significant racial difference in its prevalence. Three women were found to be thyrotoxic but none were hypothyroid. This study found a high prevalence of goitre among the pregnant Indian women, probably related to the protein malnutrition state. The high prevalence of positive thyroid antibody in our population indicates that a high percentage of women are at risk of developing postpartum thyroiditis.