Saliva Iodine Concentration in Children and Its Association with Iodine Status and Thyroid Function

CONTEXT

The effectiveness of saliva iodine concentration (SIC) in evaluating iodine status in children is not clear.

OBJECTIVE

We aimed to explore associations between SIC and assessed indicators of iodine status and thyroid function.

DESIGN

Cross-sectional study.

SETTING

Primary schools in Shandong, China.

PARTICIPANTS

Local children aged 8 to 13 years with no known thyroid disease were recruited to this study.

MAIN OUTCOME MEASURES

Blood, saliva, and urine samples were collected to evaluate thyroid function and iodine status.

RESULTS

SIC positively correlated with spot urinary iodine concentration (r = 0.29, P < 0.0001), 24-hour urinary iodine concentration (r = 0.35, P < 0.0001), and 24-hour urinary iodine excretion (r = 0.40, P < 0.0001). The prevalence of thyroid nodules (TN) and goiter showed an upward trend with SIC quantiles (P for trend < 0.05). Children with SIC <105 μg/L had a higher risk of insufficient iodine status (OR = 4.18; 95% CI, 2.67-6.56) compared with those with higher SIC. Those having SIC >273 μg/L were associated with greater risks of TN (OR = 2.70; 95% CI, 1.38-5.26) and excessive iodine status (OR = 18.56; 95% CI, 5.66-60.91) than those with lower SIC values.

CONCLUSIONS

There is a good correlation between SIC and urinary iodine concentrations. It is of significant reference value for the diagnosis of iodine deficiency with SIC of less than 105 μg/L and for the diagnosis of iodine excess and TN with SIC of more than 273 μg/L. Given the sanitary nature and convenience of saliva iodine collection, SIC is highly recommended as a good biomarker of recent iodine status in school-aged children.

Iodine deficiency in pregnant women after the adoption of the new provincial standard for salt iodization in Zhejiang Province, China

BACKGROUND

Zhejiang has achieved the goal of elimination of iodine deficiency disorders (IDD) via the implementation of universal salt iodization (USI) since 2011. Iodine content in household table salt decreased from the national standard (35 ppm) to the Zhejiang provincial standard (25 ppm) in 2012. It is crucial to periodically monitor iodine status in pregnant women because IDD in pregnancy have adverse effects on fetal neurodevelopment.

METHODS

We carried out a cross-sectional study between April 2014 and September 2015 in the eight sentinel surveillance counties across Zhejiang Province, where IDD was previously known to be endemic. A total of 1304 pregnant women participated and provided a random spot urine sample and a household table salt sample. Urinary iodine concentration (UIC) was determined using arsenic-cerium catalytic spectrophotometry. Iodine content in salt was measured using a titration method with sodium thiosulphate.

RESULTS

Overall, the median UIC of the total study population of pregnant women was 129.3 μg/L, with a higher UIC in inland (152.54 μg/L) and a lower UIC in coastal counties (107.54 μg/L). Household coverage of iodized salt was 94.6% and the rate of adequately iodized salt was 89.9%.

CONCLUSIONS

Our results indicate deficient iodine status in the pregnant population of Zhejiang, according to the lower cut-off value of optimal iodine nutrition (150 μg/L) recommended by the World Health Organization. In addition to sustaining USI, more efforts are urgently needed to improve iodine intake in women during pregnancy, especially those residing in the coastal counties.

Serum thyroglobulin as a biomarker of iodine deficiency in adult populations

OBJECTIVE

To clarify which factors may influence the serum Tg level in an adult population and how this may affect Tg as a biomarker of iodine deficiency (ID).

DESIGN AND METHODS

Two identical cross-sectional studies were performed before (C1a: 1997-98, n = 4649) and after (C2: 2004-05, n = 3570) the Danish mandatory iodine fortification (IF) of salt (2000). Additionally, a follow-up study of C1a was performed after IF (C1b: 2008-10, n = 2465). The studies took place in two regions with mild (Copenhagen) and moderate (Aalborg) ID before IF. Serum Tg was measured by immunoradiometric method and investigated as outcome variable in multivariate models.

RESULTS

Multiple factors were associated with serum Tg. Some were directly related to iodine intake (cohort, urinary iodine concentration (UIC) level and region), and some were likely mediators of iodine intake effects on Tg (thyroid nodularity, thyroid size and autonomy with low TSH). Others were caused by Tg assay interference (Tg-Ab positivity), aggravation of ID (childbirths and smoking) or TSH stimulation of the thyroid. Estimated 24-h urinary iodine excretion was a more sensitive predictor of Tg than UIC. Iodine supplement users had low median Tg values compared with nonusers both before and after IF.

CONCLUSIONS

Multiple factors should be taken into consideration when evaluating Tg as a marker of ID in adult populations, and the Tg results may depend on the assay used. Still, Tg is a sensitive marker of ID. We suggest including a reference population with known sufficient iodine intake when Tg is used to evaluate ID.

Systematic review and cost analysis comparing use of chlorhexidine with use of iodine for preoperative skin antisepsis to prevent surgical site infection

OBJECTIVE

To compare use of chlorhexidine with use of iodine for preoperative skin antisepsis with respect to effectiveness in preventing surgical site infections (SSIs) and cost.

METHODS

We searched the Agency for Healthcare Research and Quality website, the Cochrane Library, Medline, and EMBASE up to January 2010 for eligible studies. Included studies were systematic reviews, meta-analyses, or randomized controlled trials (RCTs) comparing preoperative skin antisepsis with chlorhexidine and with iodine and assessing for the outcomes of SSI or positive skin culture result after application. One reviewer extracted data and assessed individual study quality, quality of evidence for each outcome, and publication bias. Meta-analyses were performed using a fixed-effects model. Using results from the meta-analysis and cost data from the Hospital of the University of Pennsylvania, we developed a decision analytic cost-benefit model to compare the economic value, from the hospital perspective, of antisepsis with iodine versus antisepsis with 2 preparations of chlorhexidine (ie, 4% chlorhexidine bottle and single-use applicators of a 2% chlorhexidine gluconate [CHG] and 70% isopropyl alcohol [IPA] solution), and also performed sensitivity analyses.

RESULTS

Nine RCTs with a total of 3,614 patients were included in the meta-analysis. Meta-analysis revealed that chlorhexidine antisepsis was associated with significantly fewer SSIs (adjusted risk ratio, 0.64 [95% confidence interval, [0.51-0.80]) and positive skin culture results (adjusted risk ratio, 0.44 [95% confidence interval, 0.35-0.56]) than was iodine antisepsis. In the cost-benefit model baseline scenario, switching from iodine to chlorhexidine resulted in a net cost savings of $16-$26 per surgical case and $349,904-$568,594 per year for the Hospital of the University of Pennsylvania. Sensitivity analyses showed that net cost savings persisted under most circumstances.

CONCLUSIONS

Preoperative skin antisepsis with chlorhexidine is more effective than preoperative skin antisepsis with iodine for preventing SSI and results in cost savings.

Sustainable universal salt iodization in low-income countries - time to re-think strategies?

OBJECTIVE

Sustained iodine deficiency control requires sustainable mechanisms for iodine supplementation. We aim to describe the status of salt iodation machines, salt producers' experiences and quality of salt produced in Tanzania.

METHODS

Qualitative and quantitative data was collected from the factory sites, observations were made on the status of UNICEF-supplied assisted-iodation machines and convenience samples of salt from 85 salt production facilities were analysed for iodine content.

RESULTS

A total of 140 salt works visited had received 72 salt iodation machines in 1990s, but had largely abandoned them due to high running and maintenance costs. Locally devised simple technology was instead being used to iodate salt. High variability of salt iodine content was found and only 7% of samples fell within the required iodation range.

CONCLUSION

Although iodine content at factory level is highly variable, overall iodine supply to the population has been deemed largely sufficient. The need for perpetual iodine fortification requires reassessment of salt iodation techniques and production-monitoring systems to ensure sustainability. The emerging local technologies need evaluation as alternative approaches for sustaining universal salt iodation in low-income countries with many small-scale salt producers.

Iodine status and goiter prevalence after 40 years of salt iodisation in the Kangra District, India

Thirty primary schools were selected in district Kangra utilizing the population proportionate to size cluster sampling methodology in the year 2004. A total of 6939 children were included in the study. The clinical examination of the thyroid of each child was conducted. On the spot casual urine sample and salt samples were collected from a 'sub set of' children included in the study. The Total goiter rate (TGR) was found to be 19.8%. The median Urinary iodine excretion level was 200 microg/l and only 64% of the salt samples had the stipulated level of iodine. The findings of the present study revealed that current iodine status of population is adequate, however, TGR showed mild iodine deficiency (chronic) and there is a need of continued monitoring the quality of iodised salt provided to the beneficiaries under the Universal salt iodisation programme in order to achieve the goal of elimination of Iodine deficiency disorders from district Kangra.

Population living in the Red Sea State of Sudan may need urgent intervention to correct the excess dietary iodine intake

BACKGROUND

Both inadequate and high intakes of iodine are associated with thyroid disease and associated abnormalities. Consumption of foods deficient in iodine induces hypothyroidism. Conversely, excessive intake of the nutrient precipitates hyperthyroidism. Iodine deficiency causes impairment of thyroid hormonogenesis resulting in goiter (struma), cretinism which is associated with increased prenatal and infant mortality, deafness, motor disabilities and mental retardation due to damage during fetal and neonatal brain development. We have assessed the iodine status of school children from the locality of Port Sudan, Red Sea State of Eastern Sudan. The primary sources of iodine of the children are mainly iodized salt and rations supplied by local donors and various aid agencies operating in the Sudan.

METHODS

Male and female children (n=141), aged 6 to 12 years (median age 9.8 years), were selected for the survey using a multistage random sampling technique, between May 22 and August 25, 2006. All the children were assessed for urinary iodine and visible goiter. In addition, the iodine content of twenty salt samples was determined using the lodometric titration method and spot test kits. The components of other foods that are routinely consumed by the children and households were noted using a questionnaire form.

FINDINGS

Urinary iodine concentration exceeded 300 microg/l and 1000 microg/l in 65% and 9.9% of the children, respectively. The highest urinary iodine level was 1470 microg/l. The prevalence of visible goiter was 17%. All the salt samples collected from the schools had more than 150mg potassium iodate per kg of salt.

CONCLUSIONS

The results of this pilot survey reveal that excessive intake of iodine in children exists in Port Sudan. Inappropriate and unregulated local fortification of salt and lack of monitoring of the imported and donated salt is the primary reason for the excessive intake. There is an urgent need for a regulatory mechanism during the process of iodine fortification and at the point of entry of imported and donated iodized salt as well as the mode of delivery in order to avoid hyperthyroidism and associated disorders. In addition, independent professionals should critically evaluate the health impact of excessive consumption of the nutrient.

Power from below: enabling communities to ensure the provision of iodated salt in Kyrgyzstan

BACKGROUND

In Kyrgyzstan, as in many countries around the world, progress in universal salt iodization has been slow because of difficulties in enforcing existing national regulations.

OBJECTIVE

To study the effects of community testing of the iodine content of salt in households, at local retailers, and at wholesale markets on the percentage of households using iodized salt in Naryn Oblast, a region of Kyrgyzstan.

METHODS

In response to a stated community priority to address iodine deficiency in Naryn Oblast, volunteers from village health committees and personnel of Primary Health Care units living in the communities were trained in testing salt using test kits. A phased introduction of two testing components was conducted in 2002-2003 in two areas with a combined population of 160,000. The two components included testing of salt for iodine content by community members in as many households as possible (Component 1) and testing of retail salt for iodate content by community members and by retailers at wholesale markets (Component 2). Results from these two components provided the data for this study.

RESULTS

For Component 1, salt testing reached 65% of households; coverage of iodized salt increased from 87.6% to 96.8% within 5 to 7 months (averages of the two areas; p < .001), mostly owing to a great decrease in the variation among settlements. For Component 2, in area 1, the percentage of households using iodated salt increased from 71.0% to 90.3% within 5 to 7 months, whereas the percentage of households using iodinated salt decreased from 18.6% to 5.6%. In area 2, the percentage of households using iodated salt increased from 65.2% to 76.2% within 5 to 7 months, with no change in the percentage of households using iodinated salt (21.7% and 20.8%). The differences between areas I and 2 are highly significant (p < .001). At 18 to 21 months, the percentage of households using iodated salt was 97.5% in area 1 and 90.2% in area 2. The intervention cost around U.S. dollars 1500.

CONCLUSIONS

Testing salt in a large percentage of households is an effective, low-cost approach to increasing the percentage of households using iodized salt to satisfactory levels in a very short time. Empowering community members to check salt at retailers and retailers to check salt at wholesale markets with test kits for iodated salt can rapidly ensure almost exclusive consumption of iodated salt in households.

A modified ICRP 66 iodine gas uptake model and its parametric uncertainty

Intakes via inhalation may occur from radionuclides released in the form of a gas. The chemical characteristics pertaining to the release influence the intake and subsequent dose to an exposed individual. Gases are taken up or absorbed in the entire respiratory tract and the associated uptake mechanisms are quite different from deposition of particulates. Gaseous iodine can exist in various chemical forms, e.g., elemental iodine, inorganic, and organic iodine compounds. These different chemical species play an integral role in the gaseous uptake o f iodine in t he respiratory tract. Gas uptake in the various regions of the respiratory tract results in the intake of iodinated material into the body. The radioactive iodine taken up in the gas-exchange tissues is absorbed into the bloodstream of an individual and subsequently transferred to other organs. Iodine in the circulatory system can then be taken up by the thyroid gland, with resulting dose to the thyroid. The magnitude and uncertainty in regional gas uptake is important in the assessment of individuals exposed to airborne releases of radioiodine. The current ICRP 66 model is rudimentary and estimates regional gas uptake based on solubility and reactivity of the different radionuclides entering the respiratory tract. The modified model proposed here employs methodology and a mathematical structure to determine estimates of fractional gas uptake rather than defaulting to literature values, as in the current ICRP model. Model parameters have been assigned input distributions and estimates of uncertainty have been determined. A sensitivity analysis of these parameters has been performed to demonstrate the importance of each of these parameters. The sensitivity analysis ranks the model-input parameters by their importance to estimates of regional gas uptake. The model developed herein may be used for improved estimation of gas uptake in the respiratory tract and subsequent dose estimates from the different chemical forms of radioiodine.

The evaluation of the iodine content of table salt in Lesotho

The objective of the study was to investigate the iodine content of salt at both retail and household levels before the introduction of the universal salt iodisation legislation in Lesotho. A cross sectional study was conducted. 300 salt samples were collected from systematically selected households and 100 salt samples were collected from retailers situated in the same villages as the households selected for this study, in all ten districts of Lesotho. An iodometric titration method was used for analyzing the iodine content of the salt samples. The mean iodine content of salt at both retail and household level of 37 ppm ranged from 29 ppm to 48 ppm and from 31 ppm to 45 ppm in the different districts at retail and household level respectively. Uniformity of iodisation was lacking as indicated by the large variation in the mean iodine content among brands (ranging from 1-46 ppm at household level and 1-53 ppm at retail level as well as within brands (ranging from 7-97 ppm at household level and 12-76 ppm at retail level). 4% of households used non iodised salt. 18.2% of the household salt samples were below the adequate iodisation level of 15 ppm. 81.8% of the households use adequately iodised salt. This however does not meet WHO criteria for elimination of IDD as a public health problem since less than 90% of effectively iodised salt is being used at household level.

Determination of iodine values according to Hanus using 1,3-dibromo-5,5-dimethylhydantoin (DBH): analytical methods of pharmacopeias with DBH: part 7

USP/NF 2000 [The United States Pharmacopeia, Rockville USA, 24th ed., 2000, p. 1868, The National Formulary, 19th ed. 2000] and PH. EUR. 1997 [European Pharmacopoeia, third ed., Council of Europe, Strasbourg, 1997, pp. 63-64] determine the iodine values according to Hanus with iodine monobromide in glacial acetic acid. This reagent can be replaced by a solution of 1,3-dibromo-5,5-dimethylhydantoin (DBH) and potassium iodide or iodine in the same solvent. Both reagents yield equivalent results by means of method comparison according to Passing and Bablok [J. Clin. Chem. Clin. Biochem. 21 (1983) 709; 22, (1984) 431] in relation to the official method of PH. EUR.

Determination of iodine in seafood by inductively coupled plasma/mass spectrometry

A method was developed for determination of total iodine content in different standard reference materials (SRMs) and seafood products by inductively coupled plasma/mass spectrometry (ICP/MS). If iodine is present as iodide and nitric acid is used in the wet digestion system, the observed signal is not stable when iodine is measured by ICP/MS at m/z 127. To stabilize the iodine signal, 3% ammonia solution (1 + 1, v/v) was added to the digest. The limit of quantitation of the method, defined as 6 times the standard deviation in the blank solution (n = 20) was estimated to be 15 mg/kg (using 0.2 g dry mass and a dilution factor of 50). The precision, expressed as repeatability of the iodine concentration, varied between 3.2 and 12% in SRMs, with concentrations of 4.70-0.17 mg/kg dry matter. The described method was compared with a method using tetramethylammonium hydroxide extraction. Both methods showed good precision and trueness by analyses of SRMs. The 2 methods were used to determine iodine in seafood from the Barents Sea, the Norwegian Sea, and the North Sea. The results showed great variation between different fish species as well as between individuals within a species. The lowest values of iodine were recorded in muscle of ling (Molva molva) with a mean of 0.07 mg/kg fresh weight and a variation between 0.03 and 0.11 mg/kg fresh weight. The highest values were found in cod (Gadus morhua) from the Barents Sea, with a mean of 2.5 mg/kg and a variation between 0.7 and 12.7 mg/kg fresh weight.

Iodine content of commercially available iodised salt in the Sri Lankan market

OBJECTIVES

To find out whether iodised edible salt available for sale to the public is iodised, iodination is within the Sri Lanka Standards Institute (SLSI) specifications and the labelling is accurate.

DESIGN

38 packets of iodised salt from 11 different brands were randomly purchased from retail outlets in 5 different areas and analysed for iodine content, crystal size and label information.

RESULTS

All 38 packets were iodised but the iodine content in 68.6% of the packets were outside the range stipulated by the SLSI. In 52.8%, the mean iodine content was above the recommended upper limit of 40 ppm and in 15.8% below the recommended lower limit of 20 ppm. Only 31.6% of the packets were within the accepted 20 to 40 ppm range. None of the labels had all the required information.

CONCLUSIONS

Legislation enacted in 1993 stipulates that all edible salt sold for human consumption should be iodised. Our study shows that more stringent measures should be adopted to ensure that manufacturers and importers of iodised salt conform to the required specifications.

Determination of total iodine in nutritional and biological samples by ICP-MS following their combustion within an oxygen stream

A mineralization and determination method for total iodine in nutritional and biological samples is described. Combustion of the sample in an oxygen stream is followed by collection of the combustion products in a 5% water-soluble tertiary amine solution. Iodine is determined by inductively coupled plasma mass spectrometry. The accuracy and precision of the quantitative iodine analysis using standard addition is better than +/- 10%. A semi-quantitative analysis of four standard reference materials is evaluated. Owing to the presence of low-level iodine contaminant in the blank solution, the determination limit of the method is +/- 10 micrograms kg-1. Good agreement with certified iodine values is obtained for six reference materials. The use of the tertiary amine matrix solution permits the simultaneous determination of iodine and other trace metals of biological and toxicological importance, including Mn, Co, Ni, Cu, Zn, Rb, Cd, and Pb.

Toxicity considerations when revising the Nordic nutrition recommendations

The Nordic countries have issued common nutrition recommendations since 1980. In connection with the 3rd revision, a joint working group of nutritionists and toxicologists assessed the toxicology of selected trace elements. Values for upper limits of intake were established for iron, zinc, iodine and selenium. The safety factors between the lowest intakes at which adverse effects had been reported and the suggested upper limits of intake were small. In the toxicological evaluation of upper safe intake levels of essential trace elements, interactions between trace elements as well as long-term exposure to moderately elevated trace element intakes have to be considered.

Human requirements of iodine & safe use of iodised salt

Iodine deficiency is the most common preventable cause of mental deficiency. Remarkable success has been achieved by the use of iodised salt to correct this deficiency in many industrialised countries since 1920. The Government of India has adopted a strategy to iodise all edible salt in the country to overcome iodine deficiency. Universal salt iodisation is the principal public health measure for eliminating iodine deficiency disorders. Daily iodine intakes of up to 1000 micrograms, appear to be entirely safe. In India, the likelihood of exceeding this level is quite small. Iodised salt does not cause any side effects. Iodine in iodised salt does not carry risks for persons who are already iodine sufficient. iodisation of salt at the current level of fortification (15-30 ppm iodine) keeps intakes well within a safe daily range for all populations, irrespective of their iodine status.

The medical treatment of non-toxic goiter: several questions remain

In this review it is concluded that thyroxine (T4), triiodothyronine (T3) and iodine (KI), singly or in combination, are all effective in reducing the goiter size, but there is insufficient evidence to prove which is the best (possibly the combination of T4 + KI?). Higher doses are more effective than smaller, but also lead to more side-effects. Thus, the optimal dose has yet to be found. The suppression of the pituitary thyroid axis plays a major role in the treatment of non-toxic goiter, but it is not definite that this is the only mechanism responsible for the beneficial effect of the agents mentioned. In view of the lack of better evidence, it is simply suggested that non-toxic goiters in young persons should be initially treated aggressively with 200 micrograms of T4/day or more for some months. If the goiter shrinks then the dose should be gradually decreased. If the goiter persists, it is futile to continue with large doses for more than 6-12 months. One may continue with smaller doses, maintaining the serum TSH in the low-normal range. The treatment of benign thyroid nodules with thyroxine is controversial. Probably thyroxine is beneficial in about a third of the cases. For both non-toxic goiters and nodules, autonomy should be excluded before starting thyroxine treatment, and old age, cardiac disease and a poor general condition are contraindications.

Upper limit of iodine in infant formulas

Iodine is the rate-limiting substrate for thyroid hormone synthesis by the thyroid gland and must be available in threshold amounts to prevent goiter and hypothyroidism. Because excess iodine can inhibit thyroxine synthesis, an upper limit of iodine in infant formulas of 75 microg/100 kcal was proposed by the Food and Drug Administration in 1985. Review of recent studies of iodine physiology in infants and iodine content of milk suggests that a safe upper limit of iodine intake by normal, term infants should not exceed 100 microg/kg body wt daily. Given this limit and assuming the total intake of iodine to be derived from formula, the recommendation of 1985 still seems reasonable.

Suitability of a propanolic PVP-iodophor preparation as preoperative skin disinfectant: germicidal activity and chemical stability

The preparation Solutio Betadini propanolica 3% w/w, used as a pre-operative skin disinfectant was examined for its germicidal activity and its chemical stability. The additive activity of iodine and propanol resulted in a wide range of antimicrobial activity against bacteria, including bacterial spores, and fungi, with a rapid onset and sustained duration of action. The solution is easily manufactured and analyzed, its stability is guaranteed for 6 months. Because of its staining property, there is no need of coloured additives to mark the disinfected area. In addition, no skin irritations by the disinfectant were observed so far. Thus, the preparation fulfills the essential requirements for preoperative skin disinfectants and is suitable for the preparation and the compounding in hospital pharmacies.

Test method for the evaluation of virucidal efficacy of three common liquid surface disinfectants on a simulated environmental surface

The Association of Official Analytical Chemists bacterial use-dilution test for evaluating liquid surface disinfectants was modified to determine the efficacy of three common environmental germicide compounds against representatives of four virus groups. Modifications were made to conform to the Environmental Protection Agency guidelines on virucidal testing procedures. Alterations included: the use of a concentrated tissue culture preparation of virus instead of a standard bacterial culture; HEp-2 tissue culture cells as a visible test system in place of standard nutrient broth; and controls to measure the virus titer end point and the toxicity of the disinfectant to the cell cultures. Comparison of control end points with results from the test proper were the measure of the effectiveness of the germicides against the viruses. Results are described which agree with those based on other methods previously reported.