Urinary Iodine Excretion Levels Research Articles

Assessment of Iodine Deficiency Disorders in Purulia District, West Bengal, India

Iodine deficiency disorders IDD are major public health problems in India, including West Bengal. Existing programme to control IDD needs to be continuously monitored through recommended methods and indicators. The objective of this study was to assess the prevalence of goitre, status of urinary iodine excretion UIE level and to estimate iodine content of salts at the household level in Purulia district, West Bengal. A school-based, cross-sectional study was conducted during June-September 2005; among 2,400 school children, aged 8-10 years. The "30 cluster" sampling methodology and indicators for assessment of IDD, as recommended by the joint WHO/UNICEF/ICCIDD consultation, were utilized for the study. Goitre was assessed by standard palpation technique, urinary iodine excretion was analyzed by wet digestion method and salt samples were tested by spot iodine testing kit. The total goitre rate TGR was 25.9% (95% Cl=24.1-27.1%) with grade I and grade II (visible goitre) being 19.5% and 6.4% respectively. Goitre prevalence did not differ by sex but significant difference was observed in respect of age. Median urinary iodine excretion level was 9.25 microg/dl and 31.6% children had value less than 5 microg/dl. Only 33.4% of the salt samples tested had adequate iodine content of > or = 15 ppm, High goitre prevalence (25.9%) and median urinary iodine (9.25 microg/dl) below normal range indicate existence of current iodine deficiency in Purulia district. The district is still in the iodine-deficient state. Moreover, salt iodisation level far below the recommended goal highlights IDD as major public health problems in the district. Intensified information, education and communication activities along with sustained monitoring are urgently required.

Are Australian children iodine deficient? Results of the Australian National Iodine Nutrition Study

Objective: To document the population iodine nutritional status in Australian schoolchildren. Design and setting: Cross-sectional survey of schoolchildren aged 8–10 years, based on a one-stage random cluster sample drawn from all Year 4 school classes in government and non-government schools in the five mainland Australian states of New South Wales, Victoria, South Australia, Western Australia and Queensland. The study was conducted between July 2003 and December 2004. Participants: 1709 students from 88 schools (881 boys and 828 girls), representing 85% of the estimated target number of students. The class participation rate was 65%. Main outcome measures: (i) Urinary iodine excretion (UIE) levels (compared with the criteria for the severity of iodine deficiency of the World Health Organization/ International Council for the Control of Iodine Deficiency Disorders: iodine replete, UIE � 100 μg/L; mild iodine deficiency, UIE 50–99 μg/L; moderate iodine deficiency, UIE 20– 49 μg/L; severe iodine deficiency, UIE < 20 μg/L); (ii) Thyroid volumes measured by ultrasound (compared with new international reference values). Results: Overall, children in mainland Australia are borderline iodine deficient, with a national median UIE of 104 μg/L. On a state basis, NSW and Victorian children are mildly iodine deficient, with median UIE levels of 89 μg/L and 73.5 μg/L, respectively. South Australian children are borderline iodine deficient, with a median UIE of 101 μg/L. Both Queensland and Western Australian children are iodine sufficient, with median UIE levels of 136.5 μg/L and 142.5 μg/L, respectively. Thyroid volumes in Australian schoolchildren are marginally increased compared with international normative data obtained from children living in iodine sufficient countries. There was no significant association between UIE and thyroid volume. Conclusion: Our results confirm the existence of inadequate iodine intake in the Australian population, and we call for the urgent implementation of mandatory

Thirty years of a Ban on the Sale of Noniodized Salt: Impact on Iodine Nutrition in Children in Himachal Pradesh, India

A survey conducted by the central iodine-deficiency disorders team in Himachal Pradesh, a state in the goiter-endemic belt of India, revealed that 10 of its 12 districts have an endemic prevalence of goiter. The survey was conducted to provide health program managers data to determine whether it would be necessary to initiate intervention measures. To assess the status of urinary iodine excretion and household salt iodization levels after three decades of a complete ban on the sale of noniodized salt in this goiter-endemic state in India as measured by assessment of urinary iodine excretion levels and iodine content of salt at the household level. The guidelines recommended by WHO/ UNICEF/ICCIDD for a rapid assessment of salt iodization were adopted. In each of the 12 studied districts, all senior secondary schools were enlisted and one school was selected by using a random sampling procedure. Two hundred fifty children 11 to 18 years of age were included in the study. Urine samples were collected from a minimum of 170 children and analyzed using the wet digestion method. Salt samples were also collected from a minimum of 170 children and analyzed using the spot testing kit. All districts had a median urinary iodine excretion level > 200 microg/L and 82% of the families were consuming salt with an iodine content of 15 ppm or higher. The results of the present study high-light the successful implementation of the salt iodization program in the state of Himachal Pradesh. This positive impact may be due to the comprehensive strategy adopted by the state government to improve the quality of salt, development of an effective monitoring information system and effective information, education, and communication activities.

Patients with severe bowel malabsorption do not have changes in iodine status

Objective We evaluated the influence of intestinal malabsorption on iodine status in patients who had short gut syndrome and received total parenteral nutrition (group I) compared with control subjects who had eutrophia (group II) and patients who had other illnesses but normal digestive tracts (group III). Methods Twenty-seven subjects were studied. Iodine intake was determined by the measurement of iodine in ingested food and in parenteral nutrition solutions. Urinary iodine excretion was measured by the Sandell-Kalthoff reaction. Urinary creatinine, anthropometric, and thyroid hormone functions were also determined. Results Daily iodine intakes were 658 ± 125 (mean ± standard deviation), 573 ± 204, and 629 ± 208 μg for groups I, II, and III, respectively. Daily urinary iodine excretion levels were 399 ± 308, 439 ± 192, and 370 ± 268 μg and ratios of urinary iodine (micrograms) to creatinine (grams) were 614 ± 349, 354 ± 142, and 483 ± 292, respectively. There were no statistically significant differences across groups. Conclusion In Brazil the iodine provided by food, including iodized salt, has been sufficient to maintain iodine status in patients with short gut syndrome.

Doppler evaluation of pediatric goiter: Effect of mandatory iodination

The aim of this study was to evaluate the hemodynamic status of the thyroid in children with goiter after the use of iodinated dietary salt for 3 years in a region of endemic iodine deficiency. Sixty-six children between 7 and 12 years of age were included in the study. Three groups were constituted according to sonographically measured thyroid volume and urinary iodine excretion levels. Group 1 included 11 children with thyroid volumes greater than the 97th percentile according to age and sex criteria suggested by the World Health Organization International Council for Control of Iodine Deficiency Disorders and urinary iodine level lower than 100 microg/l. Group 2 included 30 children with thyroid volumes greater than the 97th percentile and urinary iodine level equal to or higher than 100 microg/l. The control group included 25 children who had normal thyroid volume and urinary iodine level. All children were examined by thyroid duplex sonography. Peak systolic velocity (PSV) and resistance index (RI) were measured in the inferior thyroid artery bilaterally. PSV in group 1 was significantly higher than in group 2 and in the control group (P < 0.05 and P < 0.01, respectively). There was no significant difference between the PSV of group 2 and the control group. The RI in groups 1 and 2 was significantly lower than in the control group (P < 0.01 and P < 0.01, respectively). There was no significant difference between the RIs of group 1 and group 2. These findings suggest an effect of iodination on thyroid hemodynamics before the size of the hyperplastic thyroid returned to normal, in keeping with normalization of the urinary iodine level.

Profile of iodine content of salt and urinary iodine excretion levels in selected districts of Tamil Nadu.

Iodine deficiency disorders (IDD) is the most common cause of preventable mental retardation in world today. Out of 29 districts in Tamil Nadu, 24 have been surveyed and all have been found to be endemic to IDD. There is a complete ban on the sale of non iodised salt in the state since 1995. The present study was conducted to assess the iodine content of salt and urinary iodine excretion levels amongst the beneficiaries in the state to help the government to strengthen the existing Universal salt iodisation (USI) programme activities. The study was undertaken in 24 districts of Tamil Nadu during the year 2001. The guidelines recommended by WHO/UNICEF/ICCIDD for a rapid assessment of salt iodisation in a district was adopted. A minimum of 150 salt samples were collected from each district by utilising the uniform sampling methodology. The iodine content of salt samples was analysed using the standard iodometric titration method. At least 60 children from each school were randomly selected and were requested to provide "on the spot" casual urine samples. The urinary iodine excretion (UIE) levels were analysed using the wet digestion method. It was observed that 62.3% of the families were consuming iodised salt with more than 5 ppm of iodine. It was found that district Perambalour had deficient iodine nutriture as revealed by the median UIE levels less than 100 micro g/l. The findings of the present study reveals the success of USI programme and highlights need for continued monitoring of the quality of salt provided to the population in order to achieve the goal of IDD elimination.

Elimination of iodine deficiency disorders in Delhi.

The present study was conducted in year 2002 in NCT of Delhi with the objective to re-assess the prevalence of iodine deficiency disorders. A total of 7009 children in the age group of 6-11 years were clinically examined for presence of goiter. A total of 991 salt samples were also collected randomly. On the spot casual urine samples were collected from 1395 children. The total goiter prevalence was found to be 6.2%. The percentage of children with urinary iodine excretion (UIE) of < 20.0, 20.0- < 50.0, 50.0-99.9 and 100.0 microg/l and above was 0.8, 1.8, 8.7 and 88.7%, respectively. The median UIE level was 200 microg/L. The assessment of iodine content of salt revealed that only 16% of the families were consuming salt with iodine content less than 5 ppm. The findings of the present study indicated that the population is in a transition phase from iodine deficient (as revealed by Total Goiter Prevalence) to iodine sufficient nutriture (as revealed by median UIE 200 microg/l). A significant progress has been achieved towards elimination of IDD from NCT of Delhi.

Residual goitre in the postiodization phase: iodine status, thiocyanate exposure and autoimmunity.

This study was done to assess goitre prevalence, thyroid functional status and cause of residual goitre among school children in the postsalt iodization phase in India. A cross-sectional study in which, 14762 school children in the age group of 6-18 years, from different States and Union territories of India, were evaluated for goitre prevalence, urinary iodine and thiocyanate excretion, functional status of the thyroid as well as serological and cytopathological markers for thyroid autoimmunity. Urinary iodine (wet ashing method), urinary thiocyanate (colourimetric method), serum thyroxine [in-house radioimmunoassay (RIA)], serum TSH (IRMA), antithyroid microsomal and antithyroglobulin antibodies (haemagglutination method) were estimated. Fine-needle aspiration cytology was performed in all goitrous subjects giving consent. The overall goitre prevalence was 23% (27.1% girls; 17.8% boys, P < 0.001). Subjects belonging to poor socio-economic strata had significantly higher goitre prevalence. Median urinary iodine excretion (UIE) in goitrous subjects (2-53 micromol/l) was significantly higher than in controls (2-24 micromol/l; P < 0.001). Levels of UIE observed among goitrous subjects showed no relationship with the presence or absence of thyroid dysfunction or with thyroid antibody status. High titres (> or = 1:1600) of TMA were present more often in goitrous subjects (6.08%) than nongoitrous controls (0.34%; P < 0.001) and in girls (7.3%) than boys (2.35%; P < 0.001). TMA positivity were significantly more among goitrous subjects with thyroid dysfunction than in euthyroid subjects. Significantly higher median urinary thiocyanate (USCN) excretion was observed in goitrous subjects (0.75 mg/dl) compared to controls (0.64 mg/dl; P < 0.001) and goitrous girls compared to goitrous boys. USCN excretion of goitrous subjects and controls showed no relationship with functional or thyroid antibody status in various groups. Persistent, albeit reduced prevalence of goitre, despite adequate iodine prophylaxis, suggests existence of additional factors in goitrogenesis in India. Thyroid autoimmunity can explain only a part of the goitre prevalence. The role of goitrogens in residual goitre prevalence is brought forth.

Status of Iodine Content of Salt and Urinary Iodine Excretion Levels in India

molecules of the essential amino acid tyrosine, regulate cellular oxidation and hence effect calorigenesis, thermoregulation and intermediary metabolism. These hormones are necessary for protein synthesis and they promote nitrogen retention, glycogenolysis, intestinal absorption of glucose and galactose, lipolysis and uptake of glucose by adipocytes. Synthesis and secretion of T and T are under the 4 3 control of the thyroid-stimulating hormone (TSH) which is secreted from the anterior lobe of the pituitary gland. TSH stimulates iodide transport from the blood into thyroid cells, oxidation of iodide to iodine and iodine binding to tyrosine. Synthesis of thyroid hormones is regulated by the levels of circulating free T and T as a 4 3

Effect of a Multiple-Micronutrient-Fortified Fruit Powder Beverage on the Nutrition Status, Physical Fitness, and Cognitive Performance of Schoolchildren in the Philippines

This study aimed to determine the effect of a multiple-micronutrient-fortified beverage on the micronutrient status, physical fitness, and cognitive performance of schoolchildren. The study was a randomized, double-blind, placebo-controlled trial of schoolchildren assigned to receive either the fortified or nonfortified beverage with or without anthelmintic therapy. Data on hemoglobin level, urinary iodine excretion (UIE) level, physical fitness, and cognitive performance were collected at baseline and at 16 weeks post-intervention. The fortified beverage significantly improved iron status among the subjects that had hemoglobin levels < 11 g/dl at baseline. The proportion of children who remained moderately to severely anemic was significantly lower among those given the fortified beverage. In the groups that received the fortified product, the median UIE level increased, whereas among those who received the placebo beverage, the median UIE level was reduced significantly. Iron- and/or iodine-deficient subjects who received the fortified beverage showed significant improvements in fitness (post-exercise reduction of heart rate) and cognitive performance (nonverbal mental ability score). The study showed that consumption of a multiple-micronutrient-fortified beverage for 16 weeks had significant effects on iron status, iodine status, physical fitness, and cognitive performance among iron- and/or iodine-deficient Filipino schoolchildren. Anthelmintic therapy improved iron status of anemic children and iodine status of the iron-adequate children at baseline but it had no effect on physical fitness and cognitive performance. The results from the clinical study showed that a multiple-micronutrient-fortified beverage could play an important role in preventing and controlling micronutrient deficiencies.

Iodine deficiency, radiation dose, and the risk of thyroid cancer among children and adolescents in the Bryansk region of Russia following the Chernobyl power station accident.

Little is known about the joint effect of iodine deficiency and radiation exposure on the risk of thyroid cancer. No epidemiological studies have been published assessing the modifying effect of iodine deficiency on radiation-induced thyroid cancer following the Chernobyl accident. A population sample of 3070 individuals (2590 ages 6-18, and 480 adults) from 75 settlements in the most highly contaminated regions of the Bryansk Oblast of Russia was identified and sampled for urinary iodine measurements in 1996, and iodine deficiency in each geopolitical unit (raion) was estimated. All cases of thyroid cancer were identified in those born 1968-1986 who were resident in the study area in May-June 1986 (34 histologically confirmed cases). The risk of thyroid cancer was examined in relation to population estimates of thyroid radiation dose and urinary iodine excretion level. The excess relative risk (ERR) of thyroid cancer was significantly associated with increasing thyroid radiation dose, and was inversely associated with urinary iodine excretion levels. There was a joint effect of radiation exposure and iodine deficiency. At 1 gray (Gy), the ERR in territories with severe iodine deficiency was approximately two times that in areas of normal iodine intake. These findings suggest that elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid. If confirmed by studies based on individuals, they may have implications for the use of stable iodine in the case of population exposure to radioactive iodine.

Prevalence of iron, vitamin A, and iodine deficiencies amongst adolescent pregnant mothers.

The present study was undertaken to assess the prevalence of iron, vitamin A and iodine deficiencies amongst rural Adolescent Pregnant Mothers (APM). Survey was conducted amongst APM in a rural block; district Udham Singh Nagar, Uttaranchal State. In the district, all blocks were enlisted and one block was randomly selected. Further, villages in the block were listed (n = 64) and five villages were randomly selected for the detailed study. All APM residing in the selected villages were included for the detailed study. The data on socio demographic parameters was collected utilizing a pre-tested semi-structured questionnaire. Anaemia was assessed by hemoglobin estimation with the help of the HemoCue instrument. Vitamin-A deficiency (VAD) was assessed by presence of night blindness utilizing a pre-tested semi structured proforma. Iodine Deficiency was assessed by the clinical examination of the thyroid gland and estimating the Urinary Iodine Excretion (UIE) levels of each subject. Nutrient intake was assessed by the 24-hr dietary recall method. One hundred and fifty one APM, belonging to low socio economic group, were selected for the study. The occupation of the families was farming, but the APM were housewives. The mean age of the APM was 17.8 +/- 1.5 yr. Eighty nine percent of the APM were in the age group 16-19 yr. Sixty percent of the APM were in the gestational age of 24 weeks and more. It was found that 46.0% of the APM were anaemic (Hb < 11.0 gm/dl). Sixteen percent of the study subjects had presence of night blindness. Fifteen percent of the subjects had Goiter. Median UIE level in the subjects studied was 95.0 micrograms/l. Concomitant prevalence of the three deficiencies was amongst 2.0% of the population. The 24-hour dietary intake revealed that the mean consumption of retinol and iron was only 13 and 28% of the recommended dietary allowance, respectively. The findings of the present study indicated that Anaemia, Vitamin A, and Iodine deficiency existed as public health problems in the APM of the study area.

Effect of a Multiple-Micronutrient-Fortified Fruit Powder Beverage on the Nutrition Status, Physical Fitness, and Cognitive Performance of Schoolchildren in the Philippines

This study aimed to determine the effect of a multiple-micronutrient-fortified beverage on the micronutrient status, physical fitness, and cognitive performance of schoolchildren. The study was a randomized, double-blind, placebo-controlled trial of schoolchildren assigned to receive either the fortified or nonfortified beverage with or without anthelmintic therapy. Data on hemoglobin level, urinary iodine excretion (UIE) level, physical fitness, and cognitive performance were collected at baseline and at 16 weeks post-intervention. The fortified beverage significantly improved iron status among the subjects that had hemoglobin levels &lt; 11 g/dl at baseline. The proportion of children who remained moderately to severely anemic was significantly lower among those given the fortified beverage. In the groups that received the fortified product, the median UIE level increased, whereas among those who received the placebo beverage, the median UIE level was reduced significantly. Iron- and/or iodine-deficient subjects who received the fortified beverage showed significant improvements in fitness (post-exercise reduction of heart rate) and cognitive performance (nonverbal mental ability score). The study showed that consumption of a multiple-micronutrient-fortified beverage for 16 weeks had significant effects on iron status, iodine status, physical fitness, and cognitive performance among iron- and/or iodine-deficient Filipino schoolchildren. Anthelmintic therapy improved iron status of anemic children and iodine status of the iron-adequate children at baseline but it had no effect on physical fitness and cognitive performance. The results from the clinical study showed that a multiple-micronutrient-fortified beverage could play an important role in preventing and controlling micronutrient deficiencies.

Status of Iodine Nutriture and Salt Iodization in Union Territory of Pondicherry, India

Deficiency of iodine causes a wide spectrum of disabilities including the implications on reproductive functions and lowering of IQ levels in school age children. The present study was conducted to assess the status of iodine nutriture and salt iodization in the entire Union Territory of Pondicherry, India. The study was conducted in all the four districts of Pondicherry. In each district 150 salt samples were collected by utilizing the uniform sampling methodology. The iodine content of salt samples was analyzed using the standard iodometric titration method. On the spot casual urine samples were collected from at least 80 children from the same school selected randomly The urinary iodine excretion (UIE) levels were analyzed using the wet digestion method It was observed that 59.7% of the families were consuming iodized salt with more than 5 ppm . It was found that 3 out of 4 districts had adequate iodine nutriture (median UIE levels more than 100 µg/l) possibly due to consumption of iodized salt by majority of the population. This study revealed the success of the salt iodization program in Pondicherry. However, there is a need for strengthening the existing monitoring and distribution system to ensure that adequately iodized salt is available for human consumption to eliminate IDD from the state.

Prevalence of goitre among school children in coastal Karnataka.

A cross sectional study was conducted in the rural field practice area of Department of Community Medicine, KMC, Manipal to find out the prevalence of goitre among school children in the age group of 8-10 years. A total of 722 children were selected from the study population by the method of probability proportion to size (PPS) stratified sampling giving due representation to both Government and private schools. Children were clinically examined for the presence of goitre and graded according to WHO guidelines. Urine and salt samples were collected from subsample to estimate the urinary iodine excretion level and iodine content in the salt respectively. Over all prevalence of goitre was 30 percent. Prevalence among males was 28.8 percent and among females it was 31.2 percent. In the both sexes goitre rate increased with the advancement of age. Prevalence of grade I and grade II goitre was 29.4 and 0.6 percent respectively. Prevalence of goitre was significantly higher among children who had urinary iodine excretion level less than optimum (<10 mcg/dl). Estimation of iodine content in the salt sample revealed that 48.3 percent of samples had adequate iodine content (>=15 ppm). There was significant increase in the goitre rate as the iodine content in the salt decreased (p=0.01). Prevalence of goitre among school children was high and therefore constituted a public health problem in this region.

Iodine deficiency disorders among school children of Malda, West Bengal, India.

A community-based, cross-sectional study was conducted among 2,392 school children, aged 8-10 years, in Malda district of West Bengal, India, in January 2001 to assess their iodine status. The children were selected through a multistage 30 cluster-sampling technique to determine the status of iodine deficiency disorders (IDD) using recommended quantifiable indicators. The prevalence of goitre was assessed clinically using the standard palpation method by the teachers of Community Medicine, and a total goitre rate of 11.3% was found with no significant gender difference (p>0.05). Urinary iodine excretion (UIE) levels of 341 study subjects, selected through systematic random sampling, were analyzed by the wet digestion method to determine biochemical iodine deficiency by the teachers of Biochemistry Department. The median UIE was 15 mcg/dL, and no child had UIE value less than 5 mcg/dL. Iodine content of 1,060 salt samples tested with spot-testing kit revealed 85.1% with adequate iodine content of > or = 15 ppm. The finding of 11.3% of total goitre rate but with no evidence of current iodine deficiency (median UIE 15 mcg/dL) indicates that the Malda district is in the transition phase from iodine-deficient to iodine-sufficient.

Assessment of iodine deficiency in Kottayam district, Kerala State: a pilot study.

Iodine is one of the essential micro-elements required for normal human growth and development. Iodine Deficiency Disorders (IDD) are an important public health problem in India. There has been no data on the prevalence of IDD from the Kottayam district, India and hence, the present pilot study was conducted in the year 1999 to assess whether iodine deficiency existed in the district or not and to estimate the iodine content of salt consumed by the population. A total of 1872 children in the age group of 6-12 years were included in the study and were clinically examined. On the spot urine samples were collected from 251 children. A total of 420 salt samples were collected randomly from the families of the children. The total goitre prevalence was found to be 7.05% in the subjects studied. It was found that the percentage of children with urinary iodine excretions of < 2, 2- < 5, 5-9 and 10 microg/dL and above were 6.4%, 6.0%, 20.7%, and 66.9%, respectively. Assessment of the iodine content of salt by the iodometric titration method revealed that 60.6% of the children were consuming salt with an iodine content of 15 p.p.m. and more, which was the stipulated level of salt iodisation. The findings of the present study indicated that the population is in a transitional phase from iodine deficient, as revealed by total goitre rate, to iodine sufficient nutriture, as revealed by the median urinary iodine excretion level of 17.5 microg/dL.

Re-emergence of iodine deficiency in Australia.

Iodine is an essential nutrient for human growth and development. The thyroid gland is dependent upon iodine for production of thyroid hormone. It is a common perception that iodine deficiency is not a major public health concern in mainland Australia, with sporadic studies carried out about a decade ago showing average urinary iodine excretion levels of around 200 microg/day. Recent evidence, however, has shown that the consumption of iodine is declining in Australia. A similar situation has occurred in the USA. The present study was designed to evaluate the urinary iodine excretion (UIE), as the indicator of iodine nutrition, in samples obtained from various demographic groups in the Sydney metropolitian area, namely: schoolchildren, healthy adult volunteers. pregnant women and patients with diabetes. Urinary iodine in spot urine sample was measured in a Technicon II autoanalyser using an in-house, semiautomated method. The results in this communication show that all four study groups had the median UIE below 100 microg/L. the criteria set by the World Health Organization for iodine repletion, and confirm what has been described previously, that iodine deficiency has reemerged in Sydney, Australia. One of the major causes of the reduced iodine intake is the reduction of iodine in milk since the dairy industry replaced iodine-rich cleaning solutions with other sanitisers. Secondly, less than 10% of the population are currently using iodised salt. A national survey into the iodine nutrition status in Australia is urgently required as part of the establishment of a systematic surveillance and legislation is required to iodise all edible salt.

Environmental Iodine Intake Affects the Type of Nonmalignant Thyroid Disease

The relationship between the iodine intake level of a population and the occurrence of thyroid diseases is U-shaped with an increase in risk from both low and high iodine intakes. Developmental brain disorders and endemic goiter caused by severe iodine deficiency may seriously deteriorate overall health status and economic performance of a population. Severe iodine deficiency with a median 24-hour urinary iodine excretion of the population below 25 microg needs immediate attention and correction. Less severe iodine deficiency with median urinary iodine excretion below 120 microg per 24 hours is associated with multinodular autonomous growth and function of the thyroid gland leading to goiter and hyperthyroidism in middle aged and elderly subjects. The lower the iodine intake, the earlier and more prominent are the abnormalities. At the other end of the spectrum, severely excessive iodine intake starting at median urinary iodine excretion levels around 800 microg per 24 hours is associated with a higher prevalence of thyroid hypofunction and goiter in children. A number of studies indicate that moderate and mild iodine excess (median urinary iodine >220 microg per 24 hours) are associated with a more frequent occurrence of hypothyroidism, especially in elderly subjects. The exact mechanism leading to this has not been clarified, and more studies are needed to define the limits of excessive iodine intake precisely. Due to the frequent occurrence of thyroid disorders, proper monitoring and control of the population iodine intake level is a cost-effective alternative to diagnosing, therapy and control of the many individual cases of thyroid diseases that might have been prevented.

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.