Iodine-deficiency disorders in the Aseer region, south-western Saudi Arabia: 20 years after the national survey and universal salt iodization.

OBJECTIVE: To study (i) the current prevalence of iodine-deficiency disorders among schoolchildren in south-western Saudi Arabia after universal salt iodization and (ii) the iodine content of table salts and water. DESIGN: Cross-sectional study on a stratified proportional allocation sample of children. Thyroid gland enlargement was assessed clinically and by ultrasound scanning. Urine, table salt and water samples were taken to measure iodine content. Settings The Aseer region, south-western Saudi Arabia. SUBJECTS: Schoolchildren aged 8-10 years. RESULTS: The study included 3046 schoolchildren. The total goitre rate amounted to 24·0 %. Prevalence of enlarged thyroid by ultrasound was 22·7 %. The median urinary iodine concentration of the study sample amounted to 17·0 µg/l. The iodine content of table salt ranged from 0 to 112 mg/kg; 22·5 % of the table salt samples were below the recommended iodine content (15 mg/kg) set by WHO. The total goitre rate increased significantly from 19·8 % among children using table salt with iodine content ≥15 mg/kg to reach 48·5 % among children using table salt with 0 mg iodine/kg. Analysis of water samples taken from schools showed that the majority of water samples (78·8 %) had an iodine content of 0 µg/l. CONCLUSIONS: The study documented that 18 years after the national study, and after more than a decade of universal salt iodization in Saudi Arabia, the problem of iodine-deficiency disorders is still endemic in the Aseer region. Efforts should focus on fostering advocacy and communication and ensuring the availability of adequately iodized salt.

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.

Control of iodine-deficiency disorders following universal salt iodization in Shenzhen, China, 1997-2011.

BACKGROUND: Since universal salt iodization (USI) was implemented in Shenzhen, China, in 1996, evaluation of the time trend of USI to indicate the control of iodine-deficiency disorders has not been performed. OBJECTIVE: To assess the time trend of median urinary iodine and total goiter rates from 1997 to 2011. METHODS: Probability-proportionate-to-size sampling was employed in the surveillance of iodine-deficiency disorders, for which schoolchildren aged 8 to 10 years were randomly selected from five districts of the city during each iodine-deficiency disorders survey. Urinary iodine content and thyroid size were measured by ammonium persulfate oxidation and B ultrasound, respectively. RESULTS: The coverage of iodized salt increased from 73.2% in 1997 to more than 90% in 2011. The median urinary iodine of children aged 8 to 10 years varied between 207.1 and 278.8 microg/L; these levels were above the urinary iodine level in 1995. The proportion of urine samples with iodine content above 300 microg/L was 45.6% in 1997 and decreased to 20.8% in 2011, indicating excessive consumption of iodine by the children. The goiter rate among children dropped from 10.8% in 1997 to 1.3% in 2011; both values were lower than the goiter rate in 1995, indicating that the spread of endemic goiter was under control. CONCLUSIONS: Preliminary elimination of iodine-deficiency disorders was achieved by USI in Shenzhen. Nevertheless, some problems still existed, such as over-iodization. To clarify the causes of excessive urinary iodine content, the various sources of iodine from the diet need to be investigated in the future.

Status of iodine deficiency in district Kangra, Himachal Pradesh after 60 years of salt iodization.

BACKGROUND/OBJECTIVES: District Kangra, Himachal Pradesh(HP), India is a known endemic area for iodine deficiency disorders (IDD) since 1956. The present study was conducted in district Kangra, Himachal Pradesh with the objective to assess the prevalence of iodine deficiency in school-age children. SUBJECTS/METHODS: A total of 1864 children in the age group of 6-12 years were included. Clinical examination of thyroid of all children was undertaken. 'On the spot' urine samples were collected from 463 children. The salt samples were collected from 327 children. RESULTS: The total goiter prevalence of 15.8% was found. The proportion of children with urinary iodine excretion (UIE) levels <50.0, 50.0-99.9 and ≥ 100 µg/l was 2.2, 14.3 and 83.5%, respectively. The median UIE level was 200 µg/l. About 82.3% of the families were consuming salt with iodine content ≥ 15 ppm. CONCLUSION: The population in district Kangra is possibly in a transition phase from iodine deficient (as revealed by total goiter rate of 15.8%) to iodine sufficiency (as revealed by median UIE levels of 200 µg/l).

Excessive iodine intake, water chemicals and endemic goitre in a Sudanese coastal area.

OBJECTIVE: To study the associations between intakes of iodine and water chemicals and the thyroid gland status of schoolchildren living in the coastal city of Port Sudan. DESIGN: In our previous nationwide study on goitre, it was observed that the prevalence of goitre was high in Port Sudan city despite high urinary iodine excretion. A cross-sectional study including schoolchildren aged 6­12 years was designed. Measurements determined the prevalence of goitre, urinary iodine concentration and thiocyanate secretion in casual urine samples, serum levels of thyroxine, triiodothyronine, thyroid-stimulating hormone and thyroglobulin, as well as the levels of Cl⁻, F⁻, Ca²âº, Mg²âº and total hardness of drinking water. SUBJECTS: Schoolchildren (n 654) aged 6­12 years. SETTING: Port Sudan city is located at the western bank of the Red Sea. The city is surrounded by a mountainous area known as the Red Sea Hills. It is the main sea port in the Sudan, inhabited by ethnically and socio-economically heterogeneous populations. RESULTS: The prevalence of goitre in Port Sudan was 34.86% while the median urinary iodine concentration was 46,4µg/dl. Out of thirty-one pupils from Port Sudan, twenty-four (77.42 %) were found to have urinary iodine concentration greater than 30µg/dl and twelve (38.71 %) had different degrees of biochemical hypothyroidism. Excessive concentrations of Cl⁻, Ca²âº, Mg²âº and water hardness (369.2, 116.48, 60.21 and 539.0mg/l, respectively) were detected in drinking water samples collected from Port Sudan that exceeded levels permitted by the WHO. CONCLUSIONS: The coastal city of Port Sudan is a goitre-endemic area. In contrast to other Sudanese cities in which endemic goitre is related to iodine deficiency, goitre in Port Sudan is associated with iodine excess. Water chemicals seemed to have no effects on thyroid status.

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.

[Urinary iodine excretion in German adults in 2005 meets WHO target]. / Jodidurie bei Ewachsenen in Deutschland 2005 im WHO-Zielbereich.

BACKGROUND: Recent regional and Germany-wide 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 German schoolchildren. There was also a decrease in thyroid size and goitre prevalence in children. No up-to-date results in adults for the whole of Germany are available. METHODS: In 2005, the authors examined the urinary iodine excretion in the spontaneous morning urine of 1,538 healthy adults in 357 places from all over Germany. The iodine was measured by the cer-arsenite method. RESULTS: The median iodine excretion amounted to 132 microg/l. There were no significant differences between age groups, sexes or regions. 64% had no iodine deficiency (> or = 100 microg/l). In 23% the deficiency was slight (50-99 microg/l), in 10% moderate (20-49 microg/l), and in 3% there was severe iodine deficiency (< 20 microg/l). 29% excreted > 200 microg iodide/l urine. CONCLUSION: According to the WHO (World Health Organization) guidelines, there is no longer an iodine deficiency in German adults.

Evidence of endemic goiter and iodine deficiency in a mountainous area of Haiti.

OBJECTIVE: To investigate reports of iodine-deficiency disorder in a specific area of Haiti. METHODS: In March 2008, this cross-sectional study was performed in an area 15 miles northeast of Jacmel, Haiti, within the Chaîne de la Selle Mountains. Before arrival of the study team, an announcement was made throughout local villages soliciting volunteers to meet at a central location. Of those who arrived, participants were selected in an attempt to sample individuals from all age groups, regardless of goiter status. After providing verbal informed consent, each participant was photographed and assigned a number to be used to protect privacy. An examiner performed palpation of the thyroid gland on each participant in accordance with World Health Organization criteria. Results of palpation were classified into 3 grades: grade 0, the thyroid gland was not palpable; grade 1, the thyroid gland was palpable but not visible; and grade 2, the thyroid gland was palpable and visible while the patient was in a normal position. Casual urine samples were collected from each participant and analyzed spectrophotometrically for urinary iodine concentration. RESULTS: Eighty-eight individuals aged 2 to 72 years participated in the study. Median urinary iodine concentration was 39 microg/L. Of the 88 participants, 82 (93%) were iodine deficient (18 [20%] were severely deficient), and 45 (51%) had goiter on physical examination, including 27 with grade 1 goiters and 18 with grade 2 goiters. CONCLUSIONS: We have documented iodine deficiency with associated endemic goiter in this previously uninvestigated Haitian population, for which world health agencies currently lack definitive data. These data have potential implications for both the local area and the country as a whole where further evaluation and treatment are needed for persons at high risk for iodine-deficiency disorder.

Iodine status in a Sherpa community in a village of the Khumbu region of Nepal.

OBJECTIVE: To assess the iodine status of Sherpa residents living in Kunde village, Khumbu region, Nepal. DESIGN: Prevalence of goitre was determined by palpation. Urinary iodine concentrations (UIC) were determined in casual morning samples, and thyroid-stimulating hormone (TSH) in finger-prick blood samples on filter paper. Dietary and demographic data were obtained via questionnaire, and selected foods analysed for iodine. SETTING: Khumbu region is an area of low soil iodine in Nepal, where the prevalence of goitre was greater than 90% in the 1960s prior to iodine intervention. SUBJECTS: Two hundred and fifteen of 219 permanent residents of Kunde were studied. RESULTS: Overall prevalence of goitre was 31% (Grade 1 goitre, 27.0%; Grade 2, 4.2%). When adjusted to a world population, goitre prevalence was 27% (95% CI 23, 32%); Grade 2 goitre prevalence was 2.8% (95% CI 1.0, 4.6%). Median UIC was 97 microg/l, but only 75 microg/l in women of childbearing age. Thirty per cent had UIC < 50 microg/l and 52% had UIC < 100 microg/l, while 31% of children aged <14 years had UIC > 300 microg/l. Ten per cent of participants had TSH concentrations >5 microU/ml. CONCLUSIONS: The prevalence of severe iodine deficiency has decreased since the 1960s, but mild iodine deficiency persists, particularly in women of childbearing age. The consumption of high-iodine uncooked instant noodles and flavour sachets by school-aged children contributed to their low prevalence of goitre and excessive UIC values. This finding may obscure a more severe iodine deficiency in the population, while increasing the risk of iodine-induced hyperthyroidism in children. Ongoing monitoring is essential.

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.

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.

[Iodine intake in Germany. Results of iodine monitoring in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]. / Jodversorgung in Deutschland. Ergebnisse des Jodmonitorings im Kinder- und Jugendgesundheitssurvey (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]. / Kein relevanter Zusammenhang zwischen Nitraturie und Strumaendemie in Deutschland.

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.