Goitre and urinary iodine excretion survey in schoolchildren of Kashmir Valley

BACKGROUND

An extensive survey on schoolchildren in Kashmir Valley in 1995 showed a high prevalence of goitre, making it imperative to have a relook at our iodine status, 15 years postiodization.

OBJECTIVE

To study the total prevalence of goitre and urinary iodine excretion (UIE) in Kashmiri schoolchildren, 15 years postiodization.

DESIGN

A cross-sectional survey, covering 9576 schoolchildren, aged 5-15 years (5988 in 6-12 year age group) was conducted. Goitres were graded as per WHO/UNICEF/ICCIDD. UIE was measured by the arsenic acid reduction in ceric ions method and was estimated in 208 subsampled children. Results were compared with that of 1995 survey.

RESULTS

The overall prevalence of goitre in the present study was 3·8% (95% CI: 3·4-4·2) and 3·7% (95% CI: 3·2-4·2) in those aged 6-12 years. No significant difference in prevalence of goitre was observed between boys and girls overall (3·6% vs 4·1%. P > 0·2), nor in the 6-12 year age group (3·3% vs 4·0%, P > 0·1). There was a significant trend of increasing prevalence of goitre with age (P < 0·005). UIE ranged from 12 to 397 μg/g.creatinine (median, 104); 11% subjects had UIE of <50 μg/g.creatinine. Overall, prevalence of goitre was significantly lower (3·8% vs 45·2%, P < 0·001), and mean UIE was significantly higher (123·6 ± 5·3 vs 49·60 ± 3·55 μg/g.creatinine, P < 0·001), compared to that in the 1995 survey.

CONCLUSION

The marked improvement in overall iodine nutrition in Kashmir Valley- one and a half decades after implementation of salt iodization should encourage healthcare providers to make tangible efforts for implementation of iodization programmes in areas with iodine deficiency.

Prevalence of goitre in Isfahan, Iran, fifteen years after initiation of universal salt iodization

This cross-sectional study investigated the prevalence of goitre in Isfahan, a centrally-located city in Iran, 15 years after the initiation of universal salt iodization. In total, 2,523 Isfahani adults (1,275 males, 1,248 females) aged > 20 years were selected by multi-stage cluster-sampling method. Goitre rate, serum thyroid-stimulating hormone (TSH), thyroxine (T4), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and urinary iodine concentration (UIC) were measured and compared between the goitrous (n = 478) and the non-goitrous (n = 2,045) participants. The total goitre rate was 19% (n = 478) of the 2,523 adults. The rate of Grade I and II goitre was 12.4% (n = 312) and 6.6% (n = 166) respectively. The total goitre rate, Grade I and II goitre were more prevalent among women than among men. Hypothyroidism was observed in 6.4% (130/2,045) and 18.6% (89/478) of the non-goitrous and goitrous participants respectively [odds ratio (OR) = 3.6, 95% confidence interval (CI) 2.7-4.9, p = 0.001]. Hyperthyroidism was present in 0.8% (17/2,045) and 5.2% (29/478) of the non-goitrous and goitrous adults respectively (OR = 9.0, 95% CI 4.9-16.6, p = 0.001). Hypothyroidism was more prevalent in Grade II than in Grade I goitre and among those without goitre (31.3%, 14.1%, and 6.4% respectively) (p = 0.001). Positive TPOAb was observed in 24% (n = 50) of the non-goitrous and 33.5% (n = 84) of the goitrous subjects (p = 0.03). Positive TPOAb was observed in 24.6% (35 of 142) of the Grade I and 45% (49 of 109) of the Grade II goitrous adults (p = 0.001). Positive TgAb was observed in 21.6% (n = 45) of the non-goitrous and 35.9% (n = 90) of the goitrous adults (p = 0.001). Positive TgAb was observed in 30.3% (43 of 142) of the Grade I and 43.1% (47 of 109) of the Grade II goitrous adults (p = 0.04). The median UIC was 18 microg/dL (range 1-80 microg/dL). It was 17.9 microg/dL and 19 microg/dL in the non-goitrous and goitrous adults respectively. After 15 years of successful universal salt iodization in Isfahan, goitre is still endemic, which may be due to thyroid autoimmunity. However, other environmental or genetic factors may have a role.

Current iodine status in Turkey

OBJECTIVES

To evaluate the current nationwide iodine status in Turkey by determining urinary iodine concentrations (UIC) and household salt iodine content. A follow- up monitoring study was also conducted in 30 urban areas.

METHODS

A school-based survey was conducted in 2007 by using multistage 'proportionate to population size' (PPS) cluster sampling method. The study population was composed of 900 school-age children (SAC) from different urban, suburban, and rural areas. UIC and iodine content of the table salt used at home were analyzed.

RESULTS

Median UIC was 107 microg/l (147 in urban, 42 in suburban and rural areas, p<0.001). There were severe iodine deficiency (ID) in 7.2%, moderate and mild ID in 20.6% and 19.3%, of the SAC, respectively. UIC was sufficient (>100 microg/l) in 50% of the study population, whereas it was excessive (>300 microg/l) in 10.5% of them. Of the 900 salt samples, 662 (73.5%) were iodized and 508 samples (56.5%) contained adequately iodized salt (iodine content >15 ppm). UIC of the study population and salt iodine levels correlated well (r=0.42, p<0.001).

CONCLUSIONS

Moderate to severe ID still exists in 27.8% of the Turkish population, which is much better compared to 1997 and 2002 surveys (i.e. 58%, 38.9%, respectively). The follow-up monitoring study (in 2007) demonstrated that ID has been eliminated in 20 of 30 cities surveyed, and median UIC was 130 microg/l. ID has been eliminated in most of the urban population, however, it is still an important problem in rural areas and in particular geographical regions, which should be the target of future programs.

Effectiveness of the iodine prophylaxis model adopted in Poland

OBJECTIVE

Most of the Polish territory has been classified as an iodine-deficient and endemic goiter area according to the International Council for Control of Iodine Deficiency (ICCIDD) criteria. In 1997 the obligatory model of iodine prophylaxis was implemented. Our investigations were aimed at the effectiveness of iodine prophylaxis in Poland.

METHODS

We assessed urinary iodine excretion and goiter prevalence in 5663 children aged 6-12 yr. The population of children from the same 27 schools was investigated from 1992 to 1994 (1406 girls and 1244 boys) and from 1999 to 2005 (1563 girls and 1450 boys) using identical laboratory and ultrasound methods.

RESULTS

We found significant increase in iodine urinary concentration (median 52 microg/l vs 93 microg/l, p<0.001) with accompanying drop in goiter prevalence (29.6% vs 5.2%, p<0.001) after implementation of iodine prophylaxis. Iodine excretion distribution changed significantly after 1997 with an increase in the percentage of children with iodine urinary concentration above 100 microg/l from 10.8% to 45.4%, respectively. A significantly higher iodine urinary concentration was observed in lowlands compared to uplands both before and after implementation of iodine prophylaxis (median, 50 microg/l vs 57 microg/l and 86 microg/l vs 114 microg/l, respectively, p<0.001). The goiter prevalence did not differ between girls and boys from 1992 to 1994 (28.8% vs 30.5%, p=0.35) and 1999 to 2005 (5.5% vs 4.9%, p=0.45).

CONCLUSIONS

Implementation of the new model of iodine prophylaxis in Poland in 1997 has led to significant increase in iodine urinary concentration and decrease in goiter prevalence among Polish schoolchildren. In the youngest group of children (6-8 yr olds), prevalence of goiter decreased to 3.2%--i.e. below endemic levels.

The Republic of Srpska Iodine Deficiency Survey 2006

OBJECTIVE

A survey related to iodine deficiency in the Republic of Srpska was first conducted in 1999 and resulted in the adoption of regulations concerning the quality of salt for human consumption. In order to reassess iodine status, we conducted the Republic of Srpska Iodine Deficiency Survey in 2006.

DESIGN

The survey was conducted in a sample of 1,200 schoolchildren using parameters recommended by WHO, UNICEF and ICCIDD: palpation of thyroid gland, iodine urinary excretion, thyroid utrasonography and content of iodine in salt.

RESULTS

The goiter prevalence in the total group indicated mild iodine deficiency in the Republic of Srpska, whereas urinary iodine excretion suggested iodine sufficiency. Only 35.7% of salt samples were adequately iodinated, 51.2% were hypo-iodinated and 13.1% were hyper-iodinated. Of the salt samples tested, 40.9% were iodinated using potassium iodide, despite the fact that this method of salt iodination is forbidden by regulations related to the quality of salt for human consumption. Higher prevalence of goiter and lower urinary iodine content was found in rural areas compared to urban ones, although the iodine content of salt did not differ between these two areas.

CONCLUSIONS

It seems that the Republic of Srpska has progressed from moderate (1999) to mild iodine deficiency with a wide range in the urinary iodine excretion values. However, the salt for human consumption is of low quality. The higher prevalence of goiter and the lower urinary iodine values in rural areas compared to urban ones may be attributed to differences in salt usage and/or nutritional factors.

[Iodine intake in Germany. Results of iodine monitoring in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

Iodine is an essential trace element which is found in too low quantities in the soil in Germany. The resulting iodine deficiency in human beings is countered by iodine prophylaxis, essentially consisting of iodised table salt and the iodisation of agricultural animal feed. In iodine monitoring during the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), the thyroid volumes of all children and adolescents from six years of age were determined using sonography. To assess iodine intake among the population, iodine excretion in the urine was also measured. The median ioduria value was 117 microg/l, putting it at the lower end of the scale of 100-200 microg/l recommended by the World Health Organisation. It can be concluded from these results that the iodine prophylaxis has been successful and that iodine intake has improved compared with the past. In accordance with the WHO recommendations there is no iodine deficiency in Germany any more; however, at the same time the population's iodine intake is at a relatively low level. The aim is at least to keep up what has been achieved, meaning that measures to improve iodine intake must not be allowed to slacken.

Iodine excretion with urine and thyrotrophic hormone concentration in normal and complicated pregnancies in the industrial region of iodine deficiency

A sufficient amount of iodine in food is necessary for the thyroid gland to produce hormones during pregnancy. The aim of our work was to evaluate iodine and thyrotrophic hormone (TSH) concentration in urine, free triiodothyronine (fT3) and thyroxine (fT4) in complicated pregnancies in Upper Silesia (region of iodine deficiency in Poland) in comparison with normal pregnancies. In both groups the iodine content in urine was evaluated by a quick test and serous concentrations of TSH, fT3 and fT4 were determined by a radioimmunological method. We found the iodine excretion with urine below 100 microg/L in 29.15% of all women under study, i.e. an insufficient supply of this element. The reduced iodine concentration in urine was found to be more often in women with imminent premature delivery. Moreover, it was found that in II trimester the concentration of iodine excreted with urine had been significantly lower comparing to the patients examined in III trimester. We found significantly higher concentration of thyrotrophic hormone in pregnant women with iodine excretion below 100 microg/L of urine. Evaluation of the iodine concentration in urine may be a simple screening test to determine the supply of this element in a diet. Moreover, our studies demonstrate the necessity for the iodine supplementation in pregnant women in the Silesian region--an area of iodine deficiency in Central Europe.

[Epidemiology of endemic goiter in Racha region]

1.034 inhabitants (270 men, 459 women and 305 children) were examined in Racha region (North-western Georgia) on endemic goiter at the age from 1 to 75. The investigated population was selected by randomized method. Diagnostic criteria for the evaluation of the degree of endemic goiter were based on the data of palpation and ultrasonography. In children iodine excretion by urine was also determined. Obtained data were analyzed by means of computer program Epi info-6. Prevalence of endemic goiter in examined population was 62,4% (45,2% in men, 72,1% in women and 62,9% in children). The highest spreading of the endemic goiter is noticed in the 21-30 year age group among women (78,8%). The main form of endemic goiter in Racha region is euthyroid diffuse goiter (56,1%). High index of spreading of endemic goiter in Racha region is caused by iodine deficiency along with irrational feeding and genetic factors.

Iodine nutritional status of school children in a rural area of Howrah district in the Gangetic West Bengal

The objective of the study was to assess the status of iodine nutrition in an area of Howrah district where iodine deficiency disorders (IDD) were reported despite the introduction of iodised salt for general use. A total of 969 school children in the age group 6-12 years of both sexes were clinically examined for goitre. On the spot 242 urine samples were collected from the children to study the iodine and thiocyanate excretion pattern and 108 edible salt samples were collected from the homes of the children to measure iodine level. Drinking water samples were collected to evaluate the bioavailability of iodine in the region. The total goitre prevalence was 37.6% (Grade 1: 32.6%; Grade 2: 4.9%). The median urinary iodine level was 35 microg/dL, 12.5% urine samples had iodine level below 10 microg/dL and no sample was found to contain iodine below 5 microg/dL. In 51.9% salt samples iodine level was below 15 ppm and the iodine level in the drinking water was about 82 microg/L. The people of the area consume foods from the vegetables of the Brassica family and mean thiocyanate level was 0.747+/-0.21 mg/dL. The-findings of the present study indicated that as per clinical criteria of WHO/UNICEF/ICCIDD, IDD is a severe public health problem though apparently there is no biochemical iodine deficiency. Overall results indicate that factors other than iodine deficiency may have a role in the persistence of endemic goitre in the post salt-iodisation in this region.

[No influence of urinary nitrate excretion on the goitre prevalence in Germany]

BACKGROUND

It has long been known that nitrate combined with iodiduria < 100 micro gI(-)/l has a goitrogenic effect. The cause is a partial blockage of the sodium- iodide symporter together with a hindrance to iodide absorption in the intestine. 90% of the intake of nitrate is excreted in urine. Therefore nitraturia provides information about the population. The rare epidemiological studies of the influence of NO(3)(-) on goitre are limited to a small selection of older, regional samples. Our aim was to investigate the role of nitrate in the occurrence of goitre in Germany.

METHODS

Using random samples from 3,059 clinically healthy persons of both sexes between 18 and 70 years old from all over Germany, we examined nitraturia and the prevalence of goitre or nodules, including the corresponding iodiduria. (Sonography: 7.5 MHz linear transducer; nitrate determination: isocratic ion chromatography; iodide determination: cerium-arsenite method.) Both the NO(3)(-) and the iodide excretion in spontaneous urine were measured in relation to 1 g creatinine. Statistical processing: Mann-Whitney U-Test, correlation analysis, multivariate linear regression analysis.

RESULTS

Median for nitraturia: 55.2 mg NO(3)(-)/g creatinine (men 61.5, women 51.5; p < 0.03). Significant increase in regional nitrate excretion from North to South and from East to West. No statistical connection between nitraturia, thyroid size and nodules. In the multivariate linear regression analysis relating to thyroid size/focal lesions, NO(3)(-) played the smallest part among the variables age, gender, body mass index, iodiduria, nitraturia. In the case of iodiduria with < 50 micro g I(-)/g creatinine (n = 71), there was a correlation between nitraturia and thyroid size (r = 0.18; p < 0.05). All persons with a nitraturia of > 60 mg NO(3)(-)/g creatinine (n = 1,166) evidenced a correlation with the thyroid size (r = 0.18; p < 0.01).

CONCLUSION

Since alimentary iodine shortage in Germany has been overcome to a large extent (iodiduria 100-200 micro gI(-)/l) and the nitrate content lies clearly below the WHO limit, the goitrogenic effect of nitrate is only of individual and not of epidemiological importance. The slight regional differences in NO(3)(-) excretion are the consequence of the nitrate content in drinking water and have no effect on the thyroid gland.

Urinary iodine concentration during pregnancy in an area of unstable dietary iodine intake in Switzerland

We prospectively investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992. Mean UIC of pregnant women [205 +/- 151 microg iodine/g creatinine (microg l/g Cr); no. = 153] steadily decreased from the first (236 +/- 180 microg l/g Cr; no. = 31) to the third trimester (183 +/- 111 microg l/g Cr, p < 0.0001; no. = 66) and differed significantly from that of the control group (91 +/- 37 microg l/g Cr, p < 0.0001; no. = 119). UIC increased 2.6-fold from levels indicating mild iodine deficiency in controls to the first trimester, demonstrating that high UIC during early gestation does not necessarily reflect a sufficient iodine supply to the overall population. Pregnancy is accompanied by important alterations in the regulation of thyroid function and iodine metabolism. Increased renal iodine clearance during pregnancy may explain increased UIC during early gestation, whereas increased thyroidal iodine clearance as well as the iodine shift from the maternal circulation to the growing fetal-placental unit, which both tend to lower the circulating serum levels of inorganic iodide, probably are the causes of the continuous decrease of UIC over the course of pregnancy. Mean UIC in our control group, as well as in one parallel and several consecutive investigations in the same region in the 1990s, was found to be below the actually recommended threshold, indicating a new tendency towards mild to moderate iodine deficiency. As salt is the main source of dietary iodine in Switzerland, its iodine concentration was therefore increased nationwide in 1998 for the fourth time, following increases in 1922, 1965 and 1980.

Endemic goiter in pregnant women: utility of the simplified classification of thyroid size by palpation and urinary iodine as screening tests

OBJECTIVE

To validate urinary iodine (I) excretion and the simplified classification of goiter by palpation, comparing them with ultrasound of the thyroid gland as the gold standard, to identify endemic goiter in pregnant women.

POPULATION AND SETTING

300 pregnant women identified in referral hospitals, in three geographic regions.

METHODS

Two endocrinologists, previously trained, evaluated thyroid size by palpation and by ultrasound. Urinary iodine excretion in a sample of urine was determined. Thyroid size below the 90th centile by ultrasound was considered normal.

RESULTS

Mean age of study women was 23 years old. The prevalence of low weight for gestational age was 39% and of anaemia 47%. Our sample distribution showed that 120 microg I/L was the best cut off for low urinary iodine excretion to identify endemic goiter in pregnant women (sensitivity 57% and specificity 70%, likelihood ratio of 1.4). The prevalence of goiter was 10% using ultrasound. Palpation had a sensitivity of identification goiter of 94% (95% CI 89-99%), a specificity of 80% (95% CI 75-85%), a likelihood ratio of 4.7, positive post-test probability of 36.5% and negative post-test probability of 99%.

CONCLUSIONS

Low urinary iodine excretion identified up to 46% of women with goiter. This test by itself is not useful as a screening tool to identify pregnant women at risk of goiter. Identification of thyroid size by palpation was a better screening test. However, when both tests were combined in parallel, up to 100% of women with goiter were correctly identified. Our results suggest that the commonly used cut off point of 100 microg I/L to identify low urinary iodine excretion may under-estimate the prevalence of iodine deficiency disorders when used during pregnancy.

[Monitoring of iodine in The Child and Adolescent Health Survey]

In the first quarter of 2003 a National Health Survey for Children and Adolescents will be started and carried out over a period of three years. In 11,300 children and adolescents between 6 and 18 years a comprehensive iodine monitoring will be realised. The volume of the thyroid gland will be determined sonographically, thyroid hormones and the urinary iodine excretion will be measured. Apart from the nutritional intake of iodine and the use of supplements, socio-demographic and other variables relevant to health will be recorded in a self-administered questionnaire. In the pilot study of the Health Survey for Children and Adolescents from March 2001 to March 2002 the method was tested on 426 children and adolescents and has proved feasible. The sample for the pretest was not representative for the population of children and adolescents in Germany but may already be an indication for the iodine supply. A low goitre prevalence of 4.2% was found. The total thyroid volume correlated significantly with height and weight. There was no significant difference between boys and girls or between a rural and an urban sample point.

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.

Dietary supplies of iodine and thiocyanate in the etiology of endemic goiter in Tripura

In the post-salt iodization phase, a study on iodine nutriture status was conducted in Tripura of North East India. The clinical variable of the study was goiter and the biochemical variables were urinary iodine and thiocyanate. Random sampling methodology was followed for selecting the study areas in the State. In each study area, the studied population consisted of school children of both sexes in the age group 6-15 years. The total study areas were 22 and the total number of the population was 10,801. The total number of urine samples were analysed for iodine and thiocyanate were 1,032 (about 10%). The total goiter rate was 21.63%. Population of most of the studied areas had no biochemical iodine deficiency as evidenced by median urinary iodine excretion levels. However, the per capita consumption of iodine of about 40% population was inadequate. A large number of cyanogenic plants (SCN precursors) are used as common vegetables. This study ensures that the existing goiter prevalence in the region could possibly due to non-uniform adequate iodine supply along with the thiocyanate load.

[Urinary iodine levels within normal range in German school-age children]

BACKGROUND

Recent regional investigations have shown that the abolition of the requirement to declare iodine in foodstuffs and the greater emphasis on information about goitre prevention led to an increase in urinary iodine excretion in Germany. There was also a decrease in thyroid size and goitre prevalence in children. No up to date results for the whole of Germany are available.

PROBANDS AND METHODS

In 1999 we examined the urinary iodine excretion in the spontaneous morning urine of 3,065 healthy 6- to 12-year-old school children in 128 places from all over Germany. The iodine was measured by the Cer-arsenit method.

RESULTS

The median iodine excretion amounted to 148 micrograms/l. There were no significant differences between age groups, sexes or regions. 73% had no iodine deficiency (> 100 micrograms/l). In 20% the deficiency was slight (50-99 micrograms/l), in 6% moderate (20-49 micrograms/l) and in 1% there was a severe iodine deficiency (< 20 micrograms/l). 8% excreted > 300 micrograms iodide per liter urine.

CONCLUSION

According to the WHO guidelines, there is no longer a iodine deficiency in Germany--at least among children prior to puberty.

Iodine prophylaxis programme in rural area of Kolhapur district of Maharashtra

It is well established that iodine deficiency is the principle cause of goiter and widely prevalent nutritional problem in India. A great number of subjects living in iodine deficient conditions have appeared to develop adequate adaptive mechanism without clinical evidence of thyroid hyperplasia. Also govt. of India has implemented compulsory use of iodized salt all over the nation since 1985 as a prophylactic measure. But the programme is criticised through various channels of publications, stating that the long term consumption of iodised salt may result in toxic effects of iodine, such as thyrotoxicosis and other thyroid related complications. A survey was carried out therefore to study the effects of prophylaxis programme among the rural community of Kolhapur district of non-endemic area and ill-effects if any, due to prolonged use of iodised salt were studied. Our study concludes that use of iodised salt has beneficial effects towards prophylactic measures against goiter. Also prolonged consumption of iodised salt in non-endemic area has not resulted in any ill-effects due to extra iodine.

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.

[Iodine therapy for iodine deficiency goiter and autoimmune thyroiditis. A prospective study]

PROBLEM

There is epidemiological and clinical evidence that iodine may induce or promote the manifestation of autoimmune thyroiditis. For this reason it is important to know if substitution of alimentary iodine deficiency or iodine treatment of endemic goitre can cause formation of thyroid antibodies. On the other hand the practical importance of this phenomenon should be evaluated.

PATIENTS AND METHODS

During a prospective study we examined 209 patients with endemic non-toxic goitre and 53 healthy people. For treatment were used 200 micrograms iodine/d (n = 119), 500 micrograms iodine/d (n = 27), 1.5 mg iodine/week (n = 41), 150 micrograms iodine/d plus 75 to 100 micrograms T4/d (n = 26), 100 micrograms iodine plus 100 micrograms T4/d (n = 24). The observation took 1 year with a 3-month interval for check ups including clinical examination, ultrasound, TSH, T3, fT4, TPO- and thyreoglobuline antibodies and urinary iodine.

RESULTS

After 12 months 7.5% of iodine treated persons had produced antibodies, most of them at low levels. In healthy people we found increased antibody-levels in 3.8%, in patients with goitre in 9.0%, in patients with nodular goitres in 11.1%. 500 micrograms iodine caused the most antibody reaction in 14.8%. People treated with 200 micrograms iodine/d showed positive antibody levels in 5%. T4 seems to reduce antibody-reactions. Pathological antibody-levels were not found in patients with combined iodine/T4- and single-T4 therapy. Among the 22 primary pathological antibody levels only 4 increased further (18.2%). Three of them belonged to the group of 5 persons treated with 500 micrograms iodine/d. Primary high antibody values were normalized in 5 patients (22.7%). Hypothyroid disturbances were not found. Ultrasound did not show any alterations, and the reduction of thyroid volumes in antibody-positive patients was not affected. Median urinary iodine excretion during the observation-interval was 5.2 to 7.2 micrograms/dl.

CONCLUSIONS

Possible antibody reactions have no clinical importance at all. Individual cases must be observed. Low iodine doses should be preferred. Combined iodine/T4 treatment seems to have an advantage regarding immunological thyroidal reactions.

[An endemic goiter study of a population in the Pyrenees (Cerdanya-Girona)]

INTRODUCTION

To evaluate the iodine deficiency, the scholar population is the most usually studied. However, the survey in general population offers information about the most affected groups. Our work was made in the frame of a health survey of Cerdanya (12,200 inhabitants), and five years after salt iodination.

AIMS

Aims.--1) Prevalence evaluation of endemic goiter and urinary iodine excretion in Cerdanya population (> 6 y.). 2) Measurement of iodine concentration in drinking water.

MATERIAL AND METHODS

492 individuals were randomly recruited (46.5% men and 53.5% women). A questionnaire and estimation of thyroid size (Pérez) were performed. Urinary iodine excretion was determined (Benotti) in 25% of the subjects. Measurement of iodine concentration in drinking water were performed.

RESULTS

Goiter prevalence (> or = Ia) was 28.7% (IC 95%: 24.8-32.6). The prevalence was higher in women (35.3% vs 21%/p < 0001). Goiter prevalence > Ia was 7.9% (IC 95%: 5.6-10.2) and for nodular goiter 3.4% (IC 95%: 1.9-4.9). In our population the goiter prevalence = Ia, decreased with age, but no significant changes age-related for goiter > or = Ib was observed. In women > or = 45 years and previous pregnancy, the prevalence was higher (35.6% vs 17.6%. p < 0.05). Median urinary iodine was 165 micrograms/l. In 81% of the population the fish consumption was higher than once a week. Mean iodine concentration in drinking water was 2.04 mg/l (2.1 SD).

CONCLUSIONS

After promote iodinated-food consumption, good results with a decrease in goiter prevalence and a increase in urinary iodine excretion were observed. Pregnancy increases the risk of goiter development. Although young people was more affected, the good level of urinary iodine excretion was the best indicator to expect progressive goiter disappearance. The low iodine concentrations in Cerdanya water drinking, explains the iodine deficiency in this area.

[Experience with iodine prophylaxis in the province of Bolzano]

Since 1981 in the province of Bolzano a "free-choice" iodine prophylaxis with iodinated dietary salt has been implemented. An epidemiological survey carried out in 1982 in 3109 schoolchildren living in this region showed an incidence of endemic goiter grade 1B-3 (WHO classification) of 23.6 +/- 14.0% and an urinary iodine excretion of 10.2 +/- 8.0 micrograms/l (colorimetric analysis) compared to the values of 39.6 +/- 17.7 micrograms/l found in a similar population of schoolchildren living in a non goitrous urban area in Northern Italy (Padua). This program of iodine prophylaxis was advertised through the local mass media. A further epidemiological survey, performed in the whole province in the year 1990, involving 1046 schoolchildren, randomly selected, showed an average goiter incidence of 1.6 +/- 1.3% and a urinary iodine excretion of 137.1 +/- 104.4 micrograms/l (ICP-MS analysis) in comparison to the values of 182.6 +/- 131.7 micrograms/l seen in the schoolchildren of the town of Padua. During the period of iodine prophylaxis the content of iodine in the commercially available iodinated dietary salt was also estimated. In 1990 the average content was 31.0 mg/kg and in 1997 was 27.1 mg/kg. These data therefore confirm the usefulness of iodinated salt in the prophylaxis of endemic goiter.

[Goiter and iodine deficiency in Veneto: study on 6285 elementary and media school children]

The aim of this paper was to determine goiter prevalence and urinary iodine excretion in the Veneto region. An extensive epidemiological survey was carried out in school-aged children visiting 6285 students and testing 1861 urinary samples. A goiter prevalence of 8.8% was found: 7.7% of grade 1A and 1.1% 1B; in the pre-mountainous area the prevalence was higher than 10% (11.7% in the Treviso and 12.7% in the Vicenza area). Urinary iodine excretion was less than 100 micrograms/Cr in about 45% of all examined children with a peak of 20% under 50 micrograms/Cr in the Vicenza district. According to the WHO criteria, the goiter prevalence in the Veneto can be considered under the limits of the epidemic standards. However the use of iodized salt seems advisable also in this area.

[Epidemiologic investigation on the prevalence of goiter and urinary excretion of iodine in the school population of the province of Reggio Emilia]

The prevalence of goiter was evaluated in a sample from the schoolchildren population of Reggio Emilia district. 1020 children underwent physical examination of thyroid gland and thyroid ultrasonography for determination of thyroid volume. Urinary iodine excretion (UIE) was measured in 837/1020 (82.1%). Iodine content was measured in water samples collected from 65 wells and 12 springs all around the district. The prevalence of goiter according to thyroid gland palpation was 26.2%. Thyroid volume was 4.74 +/- 1.87 ml, and the median UIE value 85 micrograms/l. According to the UIE classes as defined by WHO, 57.8% of all subjects showed a UIE less than 100 micrograms/l. In 57 out of 65 wells and in all the 12 springs examined, iodine was completely absent. In the remaining 8 wells, only iodine traces were found. Based on the results of physical examination of the thyroid gland, Reggio Emilia district should be regarded as an endemic goiter area. Nevertheless, thyroid volume measurement by ultrasound indicates that goiter prevalence may be markedly overestimated by palpation. The high prevalence of subjects featuring an increased thyroid volume, the low median UIE value and the poor iodine content in the local reservoirs of drinkable water suggest the opportunity for iodine prophylaxis in the Reggio Emilia district.

[Iodine deficiency and iodine prophylaxis experience in Sicily]

Twenty years ago we described an area of goiter endemia in North-Eastern Sicily. In this area endemic goiter was associated to a variable degree of iodine deficiency and, in some places, also to an increased thiocyanate urine excretion. Our studies have demonstrated a strict relationship between iodine deficiency and congenital hypothyroidism (both permanent and transient), an increased prevalence of autonomously functioning thyroid nodules and an increased prevalence of thyroid cancer (follicular and anaplastic histotypes). A number of cases of endemic cretinism have also been described. An active iodine prophylaxis program has been carried in the town of Troina in the years 1979-87, by iodinating the municipal water supply. This intervention caused the disappearance of goiter in schoolchildren in only five years. In the last 20 years the prevalence of goiter has decreased in all endemic areas probably because of the "silent prophylaxis", due to improved socio-economic conditions and industrial food consumption. Today the persistence of endemic goiter confirms the inadequacy of the silent iodine prophylaxis and the need to immediately introduce an active iodine prophylaxis in Sicily.

[Prevalence of goiter and urine iodine in a school population in an area of the Bolognese Apennines]

We evaluated goiter prevalence and urinary iodine excretion (UIE) in schoolchildren living in three villages of the Appennines in the Bologna district-Castel d'Aiano (CA), Gaggio Montano (GM) and Pietracolora (PC). 175 age-matched schoolchildren living in the urban area of Bologna were considered as control group. In the control area the presence of goiter was documented in 11 out of 175 subjects (6.3%). In the mountain area the presence of goiter was documented in 42 out of 233 subjects (18%) (p < 0.0001 vs control area). In the urban control area the UIE was 159 micrograms/l (median; range 19-298). In the mountain area the UIE was 119 micrograms/l (median; range 10-286) (p < 0.001 vs control area). We observed the highest prevalence of goiter and UIE levels < 100 micrograms/l only in the village of PC, which is still characterized by geographical isolation and rural economy.

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.

Endemic goitre and urinary iodine levels in rural communities in the Bolgatanga and Builsa districts of the upper east region of Ghana

OBJECTIVE

To ascertain the severity of IDD in some rural communities in upper east of Ghana and to urge the establishment of intervention and control measures for IDD.

SUBJECTS AND STUDY DESIGN

A total of 1061 subjects, made up of about an equal number of children (8-14 years) and women of childbearing age (15-45 years) from seven Sekoti villages and five Builsa villages of the upper east of Ghana were examined for goitre by the palpation method. In addition, every tenth subject examined, provided urine for urinary iodine determination.

RESULTS

68.8% of the subjects had goitre; 9.9% had visible goitre. The goitre rates of the children from Builsa (77.2%) were significantly higher than those from Sekoti (59.1%) [z = 4.5; p < 0.001]. The overall prevalence of goitre and visible goire in women in the two areas were 70.8% and 15.4% respectively. The women of Sekoti had more goitres (76.6%) but less visible goitres (8.8%) than those of Builsa (63.5% and 21.9%) [p < 0.001). The median urinary iodine level for the two survey areas was 1.6 micrograms/dl. 72% of subjects and urinary iodine less 2 micrograms/dl/24% had urinary iodine levels in the range 2-5 micrograms/dl and the remainder had urine iodine in the range 5-10 micrograms/dl.

CONCLUSIONS

These findings indicate severe IDD in Sekoti and Builsa areas requiring urgent action. Further studies are indicated to determine the cause(s) of the IDD endemia.

[Renal iodine excretion by students in East Germany. A prospective study 1989 to 1996]

AIM

A prospective longitudinal study was performed from 1989 to 1996 in order to check the effectiveness of prophylactic measures in Germany.

TEST PERSONS AND METHODS

In 3 periods the urinary iodine excretion was examined in 1849 adolescents from 2 regions (north, south) of former Eastern Germany.

RESULTS

The consumption of iodized salt has increased substantially since 1994. This coincides with an increase in urinary iodine excretion. The median iodine excretion found in 1989/92 (n = 744) was 39.0 micrograms/g creatinine (4.7 micrograms/dl), in 1994 (n = 123) 60.1 micrograms/g creatinine (6.0 micrograms/dl), and in 1995/96 (n = 982) 101.1 micrograms/g creatinine (9.8 micrograms/dl). However, the concentration was < 5.0 micrograms in 27.8% and < 10.0 micrograms iodine/dl in 58.0%. Regional differences were not found.

CONCLUSION

The iodine supply has been improved. However, the declared targets have not yet been met. The findings show that effective goitre prophylaxis can still be achieved while maintaining the voluntary principle.

Urinary iodine concentrations in swiss schoolchildren from the Zurich area and the Engadine valley

To prevent iodine deficiency disorders in Switzerland, table salt is currently fortified at 15 mg iodide/kg salt. However, several recent reports have suggested that urinary iodine excretion is marginal or inadequate among segments of the Swiss population, including schoolchildren. There is concern that iodine intake in Switzerland may be approaching levels associated with signs of clinical deficiency. Previous studies measuring urinary iodine in Swiss children have encompassed only a limited geographic area in central Switzerland. We have now evaluated urinary iodine concentrations in 243 schoolchildren aged 5 to 13 years from the Zurich area and the Engadine valley. The mean urinary iodine for all children was 11.3 +/- 8.7 micrograms/dl. There was no significant difference between iodine levels in urine from children in the Engadine and those from around Zurich. There were also no significant gender differences in urinary iodine concentrations. The median urinary iodine concentration for all children was 9.6 micrograms/dl, below the threshold suggested by the World Health Organization (< 10 micrograms/dl) as indicative of mild iodine deficiency. 54.3% of the children had urinary iodine concentrations < 10 micrograms/dl and 11.5% had levels < 5 micrograms/dl. The results of this study suggest that the iodine status of some Swiss schoolchildren may no longer be adequate. They indicate the importance of intermittent monitoring of iodine status in Switzerland, where dietary habits and food supply patterns are changing. They also support the recent decision (February 1998) by the Swiss Federal Department of the Interior to increase the concentration of iodide in Swiss table salt, based on the recommendations of the Fluoride-Iodine Commission of the Swiss Academy of Medical Sciences.

Dietary iodine deficiency in South Africa. Surveys before the introduction of universal salt iodisation

OBJECTIVE

To survey iodine nutritional status in several geographically separated communities in South Africa.

DESIGN

In an initial study total goitre prevalence (TGP) was correlated with urinary iodine concentration (UIC) in some 300 primary school children in a single district. Thereafter only UIC was surveyed in children from 5 additional communities.

RESULTS

In the initial survey in Mpumalanga TGP was 74.2% (23.4% visible) and the median UIC was 15.6 micrograms/l, both data indicating severe iodine deficiency in this district. Median UIC values indicated mild to severe iodine deficiency in districts in the Northern Province, moderate deficiency in the Eastern Cape, and mild deficiency in Soweto, Gauteng. Only non-black African children in Johannesburg were iodine-replete (UIC > 100.0 micrograms/l.)

CONCLUSION

Before the introduction of compulsory iodisation of salt in December 1995, dietary iodine deficiency was widespread in South Africa.

The influence of iodine deficiency on the cognitive performance of school children in Saki, south-west Nigeria

The influence of inadequate iodine intake on the thyroid status and cognitive performance of school children in Saki, a town within the goitre belt of South-western Nigeria with known environmental iodine deficiency, was assessed. One hundred and ninety-seven (197) study subjects from Saki and seventy (70) appropriately matched control subjects from Moniya, near Ibadan, the Oyo State capital were recruited into the study. The subjects were apparently healthy primary school pupils between the ages of 10 and 14 years and had been resident in the respective locality for at least two (2) years. After establishing the presence of goitre, blood was collected for thyroid function tests by venepuncture from each pupil. The cognitive function tests, Draw-A-Person (DAP) test and the Standard Progressive Matrices (SPM) were administered simultaneously to all the pupils in the class. Urine samples were collected for urinary iodine estimation. The mean urinary iodine concentration was significantly lower in Saki than in Moniya (134.81 +/- 69.86 vs 220.00 +/- 69.00 ug/L, P < 0.01). The total goitre rates (TGR) and the visible goitre rates (VGR) were 15.2% and 1.5% for Saki, and 8.6% and 4.3% for Moniya, respectively. The mean plasma total T4 was significantly lower in Saki pupils (97.55 +/- 26.64 nmol/L vs 122.52 +/- 26.51 nmol/L P < 0.05). The TSH level was higher in Saki pupils than in Moniya pupils (4.72 +/- 1.38 mU/L vs 4.26 +/- 1.28 mU/L), but the difference was not statistically significant. Scores on intelligence function tests (DAP and SPM) were lower for Saki pupils when compared with Moniya pupils, though the differences were not statistically significant. These results show that there is a mild but significant iodine deficiency disorder problem in Saki. However, the children in Saki still maintained euthyroidism and the mild degree of iodine deficiency did not seem to have adversely affected their cognitive performance.

Iodine deficiency and endemic goitre in the Langkloof area of South Africa

OBJECTIVE

To quantify the prevalence of iodine deficiency and endemic goitre in the Langkloof area.

DESIGN

A cross-sectional study.

SETTING

Four primary schools in four communities in the Langkloof.

SUBJECTS

565 primary schoolchildren from Standard 2 to Standard 5.

OUTCOME MEASURES

Clinical diagnosis of thyroid size by palpation, level of iodine in urine and drinking water samples, level of iodine in iodised salt samples from the area, percentage of households with iodised salt on the premises, and anthropometric measures of body height and weight.

RESULTS

The prevalence of endemic goitre varied from 14.3% to 30.2% in the four communities and, based on urinary iodine levels, the iodine deficiency ranged from mild to severe. Both iodised and non-iodised salt were available at the local grocery stores but only small percentages of households had iodised salt in the house. The iodine content of drinking water was low. Anthropometric indices of undernutrition indicated medium to high levels of stunting in three of the four communities, the worst being in the community with the highest goitre prevalence.

CONCLUSIONS

Endemic goitre caused by iodine deficiency is a public health problem in the Langkloof, varying in severity from mild to severe in the different communities. The impact of mandatory iodisation of table salt, introduced at the end of 1995, needs to be assessed in these communities.

[Thyroid gland ultrasound and urinary iodine excretion in children and adolescents with type I diabetes mellitus]

BACKGROUND

Date, studies on thyroid volume and urinary iodide excretion in patients with diabetes mellitus are not available. Sonographically determined parameters of the thyroid size are correlated to other anthropometrous data and the urinary iodide excretion is correlated to glucosuria, the HbA1c value and the diabetes duration.

METHOD

In this prospective study we evaluated sonographically the thyroid volume in 107 patients with type I diabetes mellitus and 112 healthy children. The urinary iodide excretion was measured photometrically by using a modified ceric ion arsenious acid method for spontaneous urinary specimen and if available for the 24 h collected urin.

RESULTS

The thyroid volume depended on site and age. A positive correlation of the thyroid volume and age, body weight and height, could be demonstrated. Referring to reference data a goitre prevalence of 30% in juvenile patients with diabetes mellitus type I was detected. Interestingly, juvenile type I diabetics presented with an average urinary iodide excretion of 183.0 micrograms iodide/g creatinine. Even the urinary iodide excretion of 162.5 micrograms iodide confirmed this increased level. The urinary iodide excretion in 24 hours correlated with glucosuria and the HbA1c level. The healthy children presented with an average urinary iodide excretion of 42.6 micrograms iodide/g creatinine. The mean value was clearly below the WHO recommendation of 150-300 micrograms iodide/g creatinine. Only 2.8% of the healthy children examined exceeded the lower limit of this range.

CONCLUSION

In addition to the existing distinct under supply of iodide we assume an increased urinary iodide excretion in context with the osmotic diuresis in juvenile diabetics. Contrary to current opinion, that these data are correlated to the daily intake of iodide, which was calculated from urinary excretion rate, this thesis could not be affirmed for juvenile diabetics. Therefore it seems reasonable to frequently control thyroid volume and thyroid function in children and adolescents with diabetes mellitus.

Current status of endemic goiter in Croatia: the results of a nationwide study (1995)

In the beginning of the nineties, 40 years after introduction of iodine prophylaxis in Croatia, on a basis of a frequent reports coming from general practitioners about the presence of a rather high prevalence of goiter among schoolchildren, a nationwide study was initiated with the aim to determine the real prevalence of goiter in the country. A total of 2856 schoolchildren of both sexes, aged 7-15 years, were included into the study. Investigations were designed in a way to cover most of geographical regions in Croatia and subjects were randomly selected. The prevalence of goiter in schoolchildren was assessed by palpation and in part by ultrasonography of the neck. At the same time urinary iodine excretion was measured and iodine content in salt samples was determined. The results have revealed the persistence of mild endemic goiter in inland parts of Croatia with the prevalence of 6-29% in the age group 7-11 years and those of 10-43% among the age group 12-15 years. The overall goiter prevalence in schoolchildren in Croatia fluctuates from 8% to 35%. Such prevalence, most probably due to less than optimum iodine intake, is unlikely to change until iodine content of the salt is increased from its present level of 10 mg of Kl per kg of salt.

[Iodine in school children. Relationship with incidence of goiter, socioeconomic group and salt intake]

In order to evaluate iodine daily intake in 5-14 year-old school children urinary iodine excretion was measured in morning urinary samples of 134 school children. This value was corrected to microgram/ 24 h according to Jolin and Escobar del Rey's formula. Thyroid size was evaluated by two expert examiners following WHO criteria. Coincidence between both examiners was indispensable to establish goiter diagnosis. We evaluated urinary samples of 134 school children (117 normal and 17 goitrous). Urinary iodine excretion mean values were significantly different between Normal: 140.04 +/- 86.28 micrograms/24 h and Goitrous: 98.24 +/- 47.91 micrograms 24 h; p < 0.005). Goiter prevalence was found to diminish significantly when urinary iodine excretion was greater than 150 micrograms/24 h (p < 0.05). Similar mean urinary iodine excretion was observed in different socioeconomic groups. No significant differences were detected in the evaluation of two most common salt trademark consumer groups. In conclusion 1) iodoprophylaxis efficacy was assessed by urinary iodine excretion, a valid means to estimate iodine intake. Acceptable mean levels of iodine intake were found in the group under study, but the individual variability was important; 2) goitrous schoolchildren showed an iodine intake lower than normal and 3) the important variability observed in the evaluated data, the assessed relation between goiter and lower iodine intake, and the high frequency of insufficient iodine intake should justify a better control of iodoprophylaxis and a more widespread information dissemination among the population and perhaps iodine supplements in specific groups.

Endemic goiter in the Jos Plateau region of northern Nigeria

This study is an endemic goiter survey of 3476 school children in 13 Local Government Councils (LGCs) and 1004 subjects in a whole community of one LGC, Plateau State, Northern Nigeria, to determine the prevalence of goiter as well as to identify some of the etiological agents involved. Results of the survey showed that the disease is highly endemic in the area with prevalence varying in places from 1 to 23% of these subjects. Females showed a markedly higher prevalence of goiter. Analysis of 729 urine samples indicated that iodine excretion ranged from 3.5 to 1.3 microgram/dl (32-154 microgram/g creatinine) and was similar to that in iodine deficient areas in the world, but no relation was observed between the prevalence of goiter and urinary iodine. Urinary thiocyanate levels were less than 0.5 mg/dl, suggesting that the role of the thiocyanate as a goitrogen is not important in the region. Thyroid hormone parameters in village subjects with goiter were similar to those in goiter endemia except serum thyroxine (T4). An interesting result found in village subjects was very high serum thyroxine binding globulin, which leads to an increase in serum T4. This study indicated that Northern Nigeria is an area of endemic goiter. Although some areas in Plateau State are iodine deficient zones, we could not conclude that the etiology of endemic goiter in this area is associated with iodine deficiency. There may be an interplay of multiple factors of etiological importance.

[Endemic goiter in Moscow and Moscow region]

Goiter prevalence and iodine excretion levels were assessed in schoolchildren aged 9 and 13 in the city of Moscow (n = 91) and the Moscow region, 60 km East of Moscow (n = 92). Goiter prevalence was evaluated by ultrasonography. In Moscow it was found to be 31.1% among children aged 9 and 17.5% among those aged 13. The respective values in the Moscow region were 47.2 and 39.3%. Medium urinary iodine levels were 6.9 to 7.5 micrograms/dl in Moscow and 4.1 to 5.4 micrograms/dl in the region. According to modern criteria, iodine deficiency in Moscow may be regarded as mild and in the region as moderate. Control programs are urgently needed tc prevent development of iodine deficiency disorders.

[Iodine deficiency in Germany]

Urinary iodine excretion was determined in 2094 adults from 36 cities in the Federal Republic of Germany. The mean concentration was 94.1 +/- 93.1, median 66 micrograms iodine/g creatinine, or 6.2 +/- 6.0, median 4,4 iodine/dl urine, respectively. 194 (9.2%) subjects had an iodine excretion > 600 micrograms iodine/g creatinine or > 40 micrograms iodine/dl, which cannot be reached by normal nutrition. The median excretion found in West Germany (70.2 micrograms iodine/g creatinine and 5.0 iodine/dl urine, respectively) was higher than in East Germany (61.3 and 3.9, respectively), however the difference was not significant. There was no slope of urinary iodine excretion from North to South. The iodine creatinine index when compared with the iodine concentration alone did not improve the epidemiological accuracy (r = 0.75, p < 0.01). The iodine intake of the population is still below the minimum of the WHO recommendation. An efficient iodized salt prophylaxis would save approximately 1.3 billion DM annually and contribute to a genuine reduction in health-care costs.

Urine iodine concentration and prevalence of goiter among rural women of child bearing ages in Northeast Thailand

Iodine deficiency was investigated in 575 women from 12 villages of Pupaman, Si Chomphu and Amphoe Chum Phae in Khon Kaen province in a project survey under Thai-German cooperation entitled "Promotion of Health and Nutrition Status of Rural Women in Northeast Thailand". The prevalence of goiter (grades 1A, 1B, 2 and 3) were 71.6 per cent in Pupaman, 58.4 per cent in Amphoe Si Chomphu and 35.1 per cent in Amphoe Chum Phae. However, the percentage of urine iodine deficiency of the women from these districts, is reversely with the palpation grading of thyroid gland. The high prevalence of goiter in Pupaman might occur due to goitrogenic effects, although the urine iodine concentration was lower than other districts. Further study about the determination of thiocyanate should be suggested in the high prevalence of goiter.

[Effect of organized general preventive administration of iodized salt on struma incidence and ioduria in 11-16-year-old children in the Jena endemic area]

In 1988 and in 1991, i.e. two and five years after the introduction of a general iod salt supply (32 mg KJO2/kg salt) in our region, we investigated the frequency of goiters and the level of iodine excretion in urine in 504 and 336 school children of 11 to 16 years of age. In 1988 the assessment of goiter size was made by inspection and palpation according to the recommendation of WHO. 36% of the school children were found to have goiters of type I b or II. The average urine excretion of iodine amounted to 46.2 +/- 37.2 micrograms Iod/g creatinine (n = 353). In 1991 we selected school children with goiters by the same criteria and found frequency (34%) to be nearly unchanged compared to 1988. Furthermore we investigated these goiters with ultrasound and confirmed the diagnosis in 100 from 107 children. The average daily urine excretion of iodine was significantly higher in 1991 (57.7 +/- 24.8 micrograms/Iod/g creatinine, n = 328) than in 1988. However this value is below the level recommended by the WHO (minimum 75 micrograms Iod/g creatinine). Despite the increase of the iodine intake over the last years, the frequency of goiters in pubertal school children in the Jena region is endemic. This fact supports the demand for a general and sufficient iodine supply.

[Incidence of endemic goiter on Reunion Island. A search for etiological factors]

In an epidemiological study carried out in Reunion Island, 1,686 randomized school children aged from 11 to 15 years were examined for goitre by cervical palpation. A detailed questionnaire was fully completed by each child and his parents. The iodine level was measured in 168 urinary samples and in the salt and water consumed in the various places investigated. The overall incidence of goitre was 8.2 percent, rising up to 19.7 percent in the mountainous part of the island. The mean urinary iodine level was 40.2 +/- 2.7 micrograms I/g creatinine (m +/- SEM) and fell to 20.0 +/- 3.7 in the highlands. Water and salt contained little iodine. A significant relationship was noted between the presence of goitre on the one hand and sex, familial incidence of goitre, cassava consumption and distance from the coast on the other hand. This study demonstrates that endemic goitre and iodine deficiency are present in a limited area of Reunion Island.

[Survey on goiter in elementary school children in the Bisagno and Trebbia valleys (Liguro-Emilian Apennines)]

The authors have made an inquiry about school-children of two villages of Northern Appennines: Bargagli and Ottone, formerly seats of endemic goiter. The disappearance of endemic goiter in the younger generations of these villages, is in accordance with previous observations by one of the writers suggesting that sheep represent an important ecologic factor in endemic areas.

Circadian rhythms in urinary trace element and electrolyte excretion in children with and without endemic goiter

Six boys and six girls 11 +/- 1.5 years of age living in the endemic goiter area of Tîrgovişte, Romania were studied. Three of the children of each sex did have a palpable endemic goiter, three did not. The children followed a diurnal activity pattern synchronized by their school routine and ate their usual three meal diet. Urine was collected at 4-hour intervals over a 24 hour span (six samples). Urinary volume, pH, total (T) solids, protein, glucose, phosphorus, uric acid, urea nitrogen, creatinine, total and nondialyzable (ND) sodium and potassium were determined by conventional methods and the total and nondialyzable (ND) portion of urinary calcium, magnesium, and zinc and the ND portion of aluminum, copper, boron, lead and silicon were determined by an inductively coupled plasma (ICP) system.

Circadian and seasonal variations in iodine excretion in children with and without endemic goiter

The urinary iodine excretion was measured in 193 children 11 +/- 1.5 years of age living in the endemic goiter area of Dîmboviţa, Romania. One hundred and thirty four of the children showed some degree of endemic goiter, 59 showed none. All children followed a diurnal activity pattern with rest during the night. They received their usual iodine supplement of 1 gm potassium iodide once a week during the school year (which included the time of all measurements made). Urine was collected in six 4-hour samples over a 24-hour span. The examinations were conducted during the months of March, June, September and December. Iodine was determined by an automated ceric ion arsenic acid method using a Technicon Autoanalyzer. Circadian and seasonal variations of urine volume and iodine excretion were statistically verified by the cosinor technique and the seasonal variations also by one way analysis of variance using the circadian means as input. A comparable circadian rhythm of iodine excretion was found in the children with and without endemic goiter, with an acrophase during the evening (20:16 with a 95% C.I., from 19:32 to 21:04). The circadian rhythm in iodine excretion has to be taken into account whenever an estimate of the 24-hour excretion is attempted from a sample covering less than the entire 24-hour span. There was a statistically significant seasonal variation of the 24-hour iodine excretion in the boys with and without endemic goiter and in the group as a whole. The 24-hour iodine excretion during March was 102 +/- 6 mcg, during June 81 +/- 4 mcg, during September 79 +/- 3 mcg and during December 102 +/- 7 mcg. The average 24-hour iodine excretion pooled over all seasons was 91 +/- 3 mcg/24 hrs in the children with and 91 +/- 5 mcg/24 hrs in the children without endemic goiter. During March and December the iodine excretion indicates an iodine intake not usually associated with a high prevalence of endemic goiter. However, during the months of June and September (and presumably even more during the months of July and August when during summer vacation no iodine supplementation was given in school) the 24-hour iodine excretion indicates some degree of iodine deficiency. The seasonal variation in urinary iodine excretion thus points to a time when increased iodine prophylaxis may be of value.