Screening a coastal population in Southern Italy: iodine deficiency and prevalence of goitre, nutritional aspects and cardiovascular risk factors

BACKGROUND AND AIM

To evaluate the prevalence of goitre by means of urinary iodine excretion, palpatory and ultrasonographic thyroid examinations in a heterogeneous population living by the sea.

METHODS AND RESULTS

We used a special self-administered questionnaire to evaluate thyroid size, iodine intake, eating habits and cardiovascular risk factors in 600 subjects with a mean age of 45 +/- 17 years: 253 men (42.3%) and 347 women (57.7%). Urinary iodine excretion was low (72.1 +/- 15.7 microg/L; median 71.2) and associated with ultrasonographic evidence of an enlarged thyroid (16%) or structural thyroid abnormalities (30%), thus allowing us to define the Salerno Gulf as a mild-moderate area of endemic goitre. All of the subjects ate a Mediterranean diet, with a mean of two portions of fish/week. The cardiovascular risk factors considered were obesity, cigarette smoking, hypertension, hypercholesterolemia, hypertriglyceridemia and diabetes, the prevalences of which were in line with those reported in other studies of similar age-matched populations.

CONCLUSIONS

The moderate intake of fish and the consumption of a Mediterranean diet did not prevent goitre. Iodine deficiency and subsequent goitre endemia are also present at sea level, probably because of a diet based on local products grown on soil with a low iodine content or possible seawater, soil and air environmental pollution that may interfere with the availability of iodine. The assessment of iodine deficiency should therefore involve the entire population and not only subjects living far from the sea.

Iodine deficiency disorders in 15 districts of India

METHODS

A multicentre study to assess iodine deficiency disorders (goitre and deaf-mutism/cretinism) in 1, 45, 264 children (6 - <12 years old) from 15 districts of ten states was carried out during 1997-2000. Urinary iodine excretion was also determined in 27481 children, while iodine content was estimated in 5881 samples of edible salt. The sampling methodology followed was a "30 cluster survey".

RESULTS

The overall prevalence of goitre was 4.78% (4.66% of grade I and 0.12% of grade II) amongst the children examined. The highest prevalence of 31.02% goitre was observed in Dehradun district, while the lowest prevalence of 0.02% goitre was recorded in Bishnupur and Badaun districts. The overall prevalence of cretinism among children examined from seven districts was 0.072% whereas that of deaf-mutism was 0.27% among children examined from 8 districts. Median urinary iodine values was marginally less than the WHO cut-off values only in children of the 3 out of the 15 districts surveyed. Iodine content was found to be adequate in 55.45% of the salt samples.

CONCLUSION

The results suggested a significant decline in the prevalence of goitre in most parts of the country.

[Analytical problems of iodine defficiency examination in Polish Nation-wide deficit control program]

The environmental iodine deficiency has been a serious problem in the Polish health care system for many years. In many European countries the prevention of iodine deficiency-related health deficits in population scale is based on edible salt supplementation with KI. In the decade of the 80-ties the iodine supplementation program in Poland was stopped, which has caused a subsequent increase in prevalence of goiter and iodine deficiency-related hypothyreosis. These diseases were observed in many regions of Poland, including the areas beyond regions of formerly known iodine deficiency endemias. In order to control the whole Polish population, iodine consumption deficit in1991 the "Polish Program of Iodine Deficiency Control and Prevention of Iodine Deficiency-related Disorders" has been established in the year 1991. In 1992--1996 a common iodine supplementation of salt used for general consumption was 20 mg KI/kg of NaCl, and in 1997 the mandatory supplementation of salt was 30 (+10) per kg of salt which has been introduced for the whole country. This paper reports the results of iodine excretion assays in school children 6-12 years old, in the years 1993--94, 1996--97 and 1999--2002 respectively. The obtained collections of iodine urine concentrations have shown distributions with a remarkable rightward skewness. Normalization of distributions required logarythmic transformation. The quartile values obtained for data collections from years 1992--94, 1996--97 and 1999--2002 have shown that in 5-7 years of iodine deficiency prevention program yielded increase in iodine excretion in morning urine samples by about 37.8 microg, while the iodine excretion median values increased from 63.5 mg/L in years 1992--1994 to 94.0 mg/L in years 1999--2001, respectively. The lower limits of iodine excretion ranges calculated as the mean value minus 2SD of transformed data for the years 1992--1994 amounted to: 7.74 mg/L and for the years 1999--2001 amounted to 14.1 microg/l, respectively. Assessing percent of children obtaining low iodine suplementation then recommended (below 50 mg/L in urine sample) amounted to 35.8% in years 1992--1994 and 15.4% in years 1999--2001 respectively.

[Comparative analysis of the efficacy of iodine prophylaxis in pregnant women living in endemic goiter areas]

AIM

To assess efficacy of different methods of iodine prophylaxis in pregnant women living in conditions of goiter endemia.

MATERIAL AND METHODS

Standard clinical, laboratory and device tests for iodine deficiency according to WHO criteria were made in 156 pregnant women living in the territory affected by goiter endemia. Of them, 121 examinees had no thyroid pathology, 35 ones had diffuse euthyroid goiter. All of them received different kinds of iodine prophylaxis.

RESULTS

The occurrence of neonatal TTH values over 5 iU/l in neonates born by mothers free of thyroid pathology on potassium iodide prophylaxis when pregnant was 9.1%. This is much lower than in conventional iodine prophylaxis--17.24% (p < 0.01). A comparative analysis of the efficacy of potassium iodide-200 in pregnant women with diffuse euthyroid goiter and its combination with L-thyroxine has shown that by the effect on lessening frequency of neonatal TTH over 5 iU/l the above schemes do not differ significantly, thyroid reduction is more prominent in pregnant women on thyroxine with potassium iodide.

CONCLUSION

The index of neonatal TTH is an objective criterium to control efficacy of different methods of iodine prophylaxis in pregnancy.

[Preoperative assessment of thyroid nodules in an endemic goiter region--possibilities and limitations]

In iodine-sufficient areas any thyroid nodule has to be regarded as potentially malignant, whereas in iodine-deficient areas (endemic goiter areas) thyroid nodules, even multinodular goiter, are frequent. The majority of thyroid nodules in an endemic goiter area can be regarded as being most likely benign and thus not all patients with multinodular goiter have to undergo surgery. The major diagnostic aim and challenge is the selection for surgery of only those patients who suffer from mechanical obstruction due to large goiter and those who present with nodules suspicious of malignancy. Thus, for these cases the question of accurately excluding or verifying malignancy is essential for the patient and the specialist of nuclear medicine or endocrinology. A variety of investigations may be used for the preoperative evaluation of thyroid nodules, although currently sonography and fine-needle biopsy have to be regarded as the key investigations to clarify preoperatively the dignity of thyroid nodules. The article presents the indications and limitations of the different methods in use for the evaluation of thyroid malignancy. The authors present a diagnostic algorithm for the preoperative evaluation of thyroid malignancy with special respect to problems occurring in a(n) (former) endemic goiter area.

Thyroid function test abnormalities in newly admitted psychiatric patients residing in an iodine-deficient area: patterns and clinical significance

OBJECTIVE

The prevalence of abnormal in-vitro thyroid function tests in psychiatric in-patients may be as high as 24%. Thus far, however, there is only limited data addressing the underlying causes of these abnormal test results, i.e. how often they can be attributed to genuine thyroid disease.

METHOD

We conducted an observational study of all in-patients admitted to our institution during 1 calendar year running analyses of total thyroxin (T4), free thyroxin index (FTI) and thyroid-stimulating hormone (TSH). Patients with abnormal test results were classified according to an algorithm which had been established previously.

RESULTS

In 243 of 880 patients with in-vitro thyroid function analysis, at least one concentration of either T4, FTI or TSH was found to be outside the reference range. Work-up according to the algorithm was completed in 848 patients; alterations were classified as representing thyroid dysfunction in 100 (41% of patients with abnormal test results), non-specific findings in 92 (38%), influence of ingested drugs in 18 (7%) and of severe physical disease in 1 (0.4%). As measures of T4 and/or FTI provided no essential information in 854 patients (97% of tested), we found that in most cases the determination of TSH alone was sufficient for demonstrating normal thyroid function.

CONCLUSION

In 27.6% of newly admitted patients living in an iodine-deficient area, at least one abnormal result in either T4, FTI or TSH values was found. Genuine thyroid disease was found in slightly less than half the patients with an abnormal value.

Moderate to severe iodine deficiency in three endemic goitre areas from the Black Sea region and the capital of Turkey

Endemic goitre is still an important and underestimated health concern in Turkey. The overall prevalence had been calculated as 30.3% by palpation in a national survey conducted in 1995. However, direct evidence that iodine deficiency (ID) is the major cause of the endemic were lacking until now. We measured sonographic thyroid volumes (STV), urinary iodine concentrations (UIC) in 1226 school age children (SAC) (9-11 year old) from Ankara the capital of Turkey located in the central Anatolia, and three highly endemic goitre areas of the Black Sea region. A considerable number of school age children (SAC) were found to have STV exceeding the recommended upper normal limits for their age and gender obtained from iodine-replete European children (i.e. 26.7, 40.3, 44.8 and 51.7% of children from Ankara, Kastamonu, Bayburt and Trabzon respectively). UIC indicated moderate to severe ID in these areas with median concentrations of 25.5, 30.5, 16.0 and 14 microg/L respectively. This study showed severe to moderate ID as the primary etiological factor for the goitre endemic observed in Ankara and the Black Sea region of Turkey.

National study on the prevalence of iodine deficiency disorders among schoolchildren 8-12 years of age in Bahrain

A cross-sectional survey of primary-school children in Bahrain was conducted to estimate the prevalence of goitre and iodine deficiency according to age, sex and area of residence. During January-May 1999, 1600 children were randomly chosen from all government schools. Children were examined for goitre and of those, 50% were randomly selected for urinary iodine level assessment. Only 26 children (1.7%) had goitre. Although median urinary iodine was above 100 microg/L, 121 of 749 children (16.2%) had low urinary iodine levels. Although iodine deficiency does not pose a significant public health problem in Bahrain, education about the nutritional value of iodized salts in the prevention of this disorder could increase public awareness.

Biochemical assessment of iodine deficiency disorders in Baroda and Dang districts of Gujarat State

OBJECTIVE

(i) To assess the severity of Iodine Deficiency Disorders (DD) in Baroda and Dang Districts of Gujarat, using biochemical prevalence indicators of IDD; and (ii) To establish a biochemical baseline, in a sub-sample of the large population of Gujarat, that could be used to monitor the effectiveness of iodine replacement program.

METHODS

1,363 children (<1-15 years) were studied and data was collected on dietary habits, anthropometric and biochemical parameters such as height, weight and urinary iodine (UI) and blood TSH respectively. BSA and BMI were calculated. Drinking water and salt were analyzed for iodine content.

RESULTS

Median true urinary iodine was 65 microg/I (interquartile-range 38-108). Mean TSH was 2.08 mU/1 (SD +/- 2.06) and 6% of the studied population had whole blood TSH values > 5 mU/1. Females from both districts were affected more by iodine deficiency as evidenced by lower true urinary iodine and higher mean TSH levels. The interfering substances were significantly higher in Baroda boys and Dang girls as compared to their counterparts (< 0.001). Boys were more malnourished than girls as evidenced by lower BMI. Dang district was more severely affected by IDD as compared to Baroda. Drinking water in Dang district was lacking in iodine content. Iodine in salt varied at around 7 to 2000 PPM.

CONCLUSIONS

IDD is a public health problem in Gujarat. Baroda district is a new pocket of IDD. Dang district is the worse affected. The expression of IDD in these two districts of Gujarat revealed interplay of multiple factors.

Changes in serum thyroid hormone levels in newborn calves as a diagnostic index of endemic goiter

Maximum serum thyroxine (T4) and triiodothyronine (T3) levels of healthy calves were seen at 1 day after birth, and thereafter rapidly decreased until 5 days after birth. They stabilized until 2 weeks after birth, then gradually decreased until 4 weeks after birth. Serum T4 levels of calves with endemic goiter tended to be lower than those of healthy ones, but showed similar levels to those of adult cows. T3 levels of calves with goiter were similar to those of healthy ones, but showed higher variation. T4/T3 ratio of calves with goiter were significantly lower than those of healthy ones and adult cows. While individual levels of serum T4 and T3 at just after birth could not be considered as a diagnostic index, the T4/T3 ratio could be adopted as a diagnostic index of endemic goiter.

Assessment of iodine deficiency disorders using the 30 cluster approach in district Kangra, Himachal Pradesh, India

Iodine deficiency is an important public health problem in Himachal Pradesh. District Kangra is a known iodine deficiency endemic area. A survey conducted in 1956 reported a goitre prevalence of 55 per cent in the district. A more recent pilot study (1994) in four blocks of the district reported the total goitre rate (TGR) as 7 per cent. A continued prevalence of goitre in more than 5 per cent of school-aged children was found in pilot study, in spite of the distribution of iodised salt. The present study was conducted to assess the prevalence of iodine deficiency disorders (IDD) and to estimate the iodine content of salt consumed by the population in district Kangra. The '30 cluster' sampling methodology and indicators for assessment of IDD, as recommended by the joint WHO/UNICEF/ICCIDD consultation, were utilized for the survey. A confidence level of 95 per cent, a relative precision of 10 per cent and a design effect of three were taken into account for calculation of the sample size. A total of 23,348 school children in the age group 6-11 years were included in the study. The total goitre prevalence rate was found to be 12.1 per cent. The median urinary iodine excretion of the children studied was found to the 15.00 mcg/dl. About 12.7 per cent of families consumed salt with an iodine content of less than 15 ppm. The results of the present study indicated that the population of district Kangra is in a transition phase from iodine deficient to iodine sufficient nutrition and that there is a need for further strengthening of the system of monitoring the quality of iodised salt made available to the population to eliminate IDD from the Kangra Valley.

Iodine status of children and use of iodized salt in Tarai region of North India

A study was planned to investigate the iodine status of children 10-12 years old and the use of iodized salt. Goitre prevalence was estimated in 770 children between the ages of 10-12 years. The overall prevalence was 38.18 per cent. Urinary iodine excretion was also estimated in morning samples. A total of 41.43 per cent children suffered from iodine deficiency disorder (IDD) in the Tarai area. To obtain the iodine intake, salt samples from the children's families were collected and analysed for iodine content. Salt samples having 15 ppm or more of iodine were 95.53 per cent while 1.69 per cent samples were totally devoid of iodine content. It can be concluded that in spite of adequate availability and consumption of iodized salt, IDD still exists and is endemic in the region.

Goitre prevalence and thyroid abnormalities at ultrasonography: a comparative epidemiological study in two regions with slightly different iodine status

OBJECTIVE

The association between severe iodine deficiency and endemic goitre is well established, but little information is available on the relation between milder degrees of iodine deficiency and goitre prevalence.

SUBJECTS

In a comparative epidemiological study performed in two regions in Denmark, we examined 4649 subjects from the general population, women aged 18-65 years and men aged 60-65 years.

METHODS

Ultrasonography and palpation of the thyroid was performed in all participants. Iodine excretion was measured in casual urine samples. Previous thyroid disease was detected by questionnaires, personal interviews and tracing of records.

RESULTS

The median iodine excretion was 61 microg/l (mild iodine deficiency (ID)) and 45 microg/l (moderate ID) in the two regions. Median thyroid volume at ultrasonography was 11. 9 ml (mild ID) and 13.6 ml (moderate ID), P <0.001, and thyroid enlargement was found in 15.0% (mild ID) and 22.6% (moderate ID), P<0.001. Goitre prevalence increased in both regions with age to the age group 40-45 years, but not after that age. Subjects who had moved from the moderate ID to the mild ID area had the same prevalence of thyroid enlargement as the subjects staying permanently in the mild ID area. Thyroid nodules at ultrasonography were found in 30% in both regions, but nodules were larger and more often palpable in the moderate ID area. Palpable goitre was found in 9.8% (mild ID) and 14.6% (moderate ID), P<0.001. The greatest regional difference in thyroid abnormalities was found among men.

CONCLUSION

Marked differences in the prevalence of thyroid abnormalities were found in these regions with modest differences in iodine excretion.

[Diagnosis and therapy of patients with euthyroid goiter]

Nontoxic goitre is common, even in areas where iodine intake is sufficient. The most important symptoms and signs of nontoxic goitre are caused by compression of vital structures in the neck or upper thoracic cavity. In any patient with goitre the serum concentration of thyroid-stimulating hormone (TSH) should be measured to detect or exclude clinically inapparent (subclinical) hyper- or hypothyroidism. CT and MRI are expensive but very sensitive methods to identify tracheal compression and to determine intrathoracic extension. Thyroid ultrasonography and scintigraphy are not routinely indicated. Fine-needle aspiration biopsy is indicated in patients with fast-growing nodules and nodules that have a firmer consistency than other nodules within the gland. Thyroidectomy is standard therapy for young and otherwise healthy patients, especially when prompt decompression of vital structures is required. Radioiodine therapy is an attractive alternative to surgery in older patients, in those with cardiopulmonary disease, and in those with recurrent goitre. Thyroxin therapy may be tried in young patients with small, diffuse goitres who have normal serum TSH concentrations.

Assessment of goiter in an area of endemic iodine deficiency

Urinary iodone (UI) excretion and sonographically measured thyroid volume were investigated in 195 subjects living in 6 separate villages in the Casamance region of southeastern Senegal, West Africa. A comparison of goiter prevalence using thyroid palpation and volume measurement and of iodine excretion expressed as micrograms per gram (microg/g) creatinine or micrograms per deciliter (microg/dl) urine was undertaken, and possible pathogenetic factors were investigated. Ultrasound measured thyroid volumes were above the recommended upper limit of the reference range for an area replete in iodine in 83.1% or females, 52.3% of males, and 80.0% of children aged 13 years or younger. Overall sensitivity and specificity for palpation compared to sonographically demonstrated thyroid enlargement was 51.7% and 91.5%, respectively. Thyroid enlargement was not associated with ethnic origin, thiocyanate ingestion, HLA DR/DQ phenotype frequency, or thyroid growth-stimulating immunoglobulin (TGI) positivity. Median UI was 32 microg/g creatinine with 65.0% having values consistent with iodine deficiency (< 50 microg/g). When results were expressed as micrograms per deciliter, the percentage having values consistent with iodine deficiency (< 5.0 microg/dl) increased to 95.7%. The findings suggest a primary role for iodine deficiency in goitrogenesis in the study population. They demonstrate that classification of the severity of the endemia in this or other study populations in areas of iodine deficiency is dependent on the methods used to determine goiter prevalence (palpation or ultrasound measured thyroid enlargement), or dietary iodine status (iodine excretion expressed as micrograms per gram creatinine or micrograms per deciliter urine).

Urinary iodine excretion as a predictor of the iodine content of breast milk

Endemic goitre has re-emerged in Thailand. This is particularly dangerous for children since iodine deficiency disorders (IDDs) might negatively influence their intellectual and mental development. In order to assess the situation, the iodine content of breast milk was determined and a method is proposed on how to monitor IDDs in lactating mothers later on. Seventy-five lactating women aged from 15 to 45 years, from 12 villages of 3 districts, namely Chumpae. Srichompu and Pupaman within the mountainous areas of Khon Kaen province, Northeast of Thailand were investigated. The breast milk from 46.7 per cent of mothers was found to be below recommended standards. In addition, 52.0 per cent of the women investigated had low urinary iodine excretion. The risk of women with low iodine excretion was 15 fold higher in comparison to women with sufficient iodine excretion to provide breast milk for their babies with insufficient iodine content. It is concluded that urinary iodine excretion can be used to monitor the IDDs in lactating mothers.

[Epidemiology of iodine deficiency in the middle Ob regions]

AIM

Epidemiological rvaluation of goiter endemia and iodine deficiency in population of the Middle Ob region.

MATERIALS AND METHODS

Thyroid palpation and ultrasonic investigations, iodine measurements in the urine were made in 6256 children and adolescents aged 8-17 years.

RESULTS

Euthyroid condition was clinically stated in all the examinees. Palpation discovered thyroid enlargement in 36.78% of the examinees. Age prevalence was: 27.3, 33.28, 42.8, 46.18% in children and adolescents aged 8-10, 11-12, 13-14 and 15-17 years, respectively. Ultrasound detected goiter in 30.6% of the examinees. The occurrence was 34.78, 31.68, 28.2, 19.8% in the above age groups, respectively. No significant differences by thyroid size existed in girls versus boys. Urinary iodine was low in all the age groups.

CONCLUSION

The Middle Ob regions belong to zone of goiter endemia with mild to moderate iodine deficiency. This dictates the necessity of introduction of special programs of iodine deficiency control and prevention.

[Current situation of goiter endemic and iodine intake in the population of the Pyrenees and the Segrià region of Lleida]

OBJECTIVE

To assess the prevalence of goiter in five areas of the Pyrineans and in the region of Segrià in Lleida.

DESIGN

Transversal descriptive study.

SETTING

Five Pyrinean's regions and Segrià.

PATIENTS

Randomised selection of a sample of 601 subjects from the population over 6 years old.

MEASUREMENTS

The field work, which was preceded by an informative campaign in the media, was carried out from October of 1994 through February of 1995. Survey with a personal interview, blood pressure, weight, height, goiter palpation, blood analysis with thyroidal hormones and urine analysis with the iodine/creatine ratio determination.

RESULTS

The prevalence of goiter was 18.3% which was higher among women, the ratio being 3.7/1 (women/men). No significant differences were found in regard to geographic distribution. Mean iodinuria was 120 micrograms/l, though it was below 50 in 11.1% subjects. The prevalence of goiter has been founded to be related to age, increasing from the age of 45 onwards. Higher percentage of goiter was found among individuals with a family history of the disease and women who have had children. The prevalence of hypothyroidism was 3.4%.

CONCLUSIONS

We have found a medium degree of goiter's endemia in the study area, the mean iodinuria in the population is in normal range. The women with children have a higher prevalence of goiter probably due to a lack of sufficient iodine intake being a subgroup at risk.

Investigations of thyroid diseases--an update on diagnostic methods

Iodine deficiency disorders (IDD) are an important public health problem in India. It requires further refinement and improvements in thyroid disease diagnosis, especially in the early diagnosis of thyroid malfunctioning and risk assessment of autonomously functioning thyroid tissue. Scintigraphy with technetium-99m pertechnetate under exogenous or endogenous thyroid stimulating hormone (TSH) suppression provides the best results. There has been significant improvement in methodology in various laboratory investigations that have resulted from the application of newer luminescent techniques and gene technology in various thyroid function tests. TSH measurement especially by using second or third generation assays has ensured diagnostic accuracy and thyrotropin releasing hormone (TRH) test now almost always unnecessary. Determination of glycosaminoglycans in urine may become a helpful tool in the follow up of endocrine ophthalmopathy. The differentiation of blocking and stimulating TSH receptor antibodies is relevant when discrepant results are obtained with respect to thyroid function. Some newer imaging agents have been used in thyroid disease scintigraphy such as octreotide or in thyroid diseases diagnosis such as fluorodeoxyglucose. Both improve the detectability of thyroid cancer metastasis especially if radioiodine scan is negative.