Effectiveness Of Iodine Prophylaxis Research Articles

Neonatal Thyroid-Stimulating Hormone Screening as an Indirect Method for the Assessment of Iodine Status in Central Siberia

Background: Iodine deficiency is associated with goiter and impaired brain function. Neonatal thyroid-stimulating hormone (TSH) screening for congenital hypothyroidism used as an indicator of the degree of iodine deficiency and of its control. An increased frequency of thyroid-stimulating hormone (TSH) measurements above 5 mIU/L in newborn screening corresponds to the impaired iodine status of the population. The aim: to estimate the iodine deficiency and the effectiveness of iodine prophylaxis in Krasnoyarsk territory, Republics of Tuva and Khakassia according the results of neonatal TSH_screening. Methods: An 18-year analysis was performed in 34,980 newborns participating in the national thyroid newborn screening program. The TSH concentration was measured in dry blood spots collected by heel stick on filter paper, 96 hours after birth, using DELFIA method. Results: According to the data of the congenital hypothyroidism screening the rate of TSH < 5 mU/1 was 11.8% in Krasnoyarsk territory (23.9% in 2000) and corresponded to mild iodine deficiency. In different regions of Krasnoyarsk territory the rate of TSH < 5 mU/1 in the newborn varied from 3.5% to 23.7%. The highest values were marked in the Arctic peninsula Taimyr, in cities Zheleznogorsk (nuclear facility) and Sosnovoborsk, in Irbeysky, Suchobuzimsky, Eniseysky, Tuchtetsky, Novoselovsky regions (20.9–23.7%). In the Republic of Khakasia the rate of TSH < 5 mU/1 was 12.5%. In the Republic of Tyva the rate of TSH < 5 mU/1 was – 6.6% (38.6% in 1997; 11.5% in 2000). These results indicate mild iodine deficiency. Conclusion: Our investigations show mild iodine deficiency in Central Siberia demanding continuous adequate iodine prevention. Additional assessment of the iodine intake in the regions with mild iodine deficiency is needed to prevent suboptimal cognitive and psychomotor outcomes.

Neonatal gipertireotropinemiya – an indicator of the severity of iodine deficiency in the population?

Aims. Rate the severity of iodine deficiency and the effectiveness of iodine prophylaxis in the Tyumen region on the basis of the criterion of neonatal hyperthyreotropinemy than 5 mU/l for the period from 1994–2014 and to determine the significance of the indicator as the monitoring of iodine deficiency in the population. Materials and methods. Analysis of screening for congenital hypothyroidism in the period from 1994–2014’s was performed in Tyumen region as an example of the region with implemented a program of prevention of iodine deficiency. Consider the views pregnant women and mothers of children of school age in the prevention of iodine deficiency by the survey. Results. In the process of implementation of regional programs for the prevention of iodine deficiency was a significant reduction in the incidence of neonatal TSH above 5 mU/l from 44.7% in 1995 to 5% in 2013. Pregnant women use of drugs iodine on group prevention iodine deficiency unequal conditions with a population for sources of iodine, so there is open the question of objective criteria neonatal TSH > 5 mU/l, as an indicator of the severity of iodine deficiency in the territory. Correlation analysis of the severity indicators of iodine deficiency showed that in the region with implementing a program of iodine prophylaxis in group of pregnant women, indicator iodine deficiency – neonatal TSH > 5 mU/l can be used to assess the severity of iodine deficiency in a population of pregnant women only. Revealed low awareness of pregnant women (61%) and mothers of pupils (66%) of the problem of iodine deficiency. Awareness about the means of prevention is higher. For example, 78% of respondents noted “the use of iodized salt”. An important feature observed in the prevention of iodine deficiency are different models of behavior: pregnant women under medical supervision implement prevention group using drugs iodine, and women in the status of “parent” does not have this preventive practice. The proportion of respondents using iodized salt was not significantly different. Conclusions. Therefore, pregnant (lactating) women and their newborn babies within the group prophylaxis have an advantage over children, students and their parents in the prevention of iodine deficiency in the territory endemic for iodine.

Prevalence of iodine deficiency disorders and effectiveness of iodine prophylaxis among the population of reproductive age living in Saint Petersburg

The purpose of the study is the assessment of iodine status and effectiveness of iodine prophylaxis among the population of reproductive age. In this regard, we examined 200 individuals from 18 up to 44 years old living in Saint Petersburg for more than 3 years permanently. Most of the examined individuals had mild iodine deficiency, less than half of people of reproductive age (46 %) used iodized salt at home. Goiter was found by palpation in 8 % of participants. More than half of the surveyed individuals are women of reproductive age who are at risk for the development of iodine deficiency disorders. Our data reflect an unfavorable situation in fight against iodine deficiency disorders in Saint Petersburg. Probably, the voluntary model of using iodized salt as the prevention of iodine deficiency in the Russian Federation is not effective enough.

Evaluation of the effectiveness of iodine prophylaxis in Poland based on the examination of school-age children in Opoczno

In 1997 a currently operating, obligatory model of iodine prophylaxis, based on mandatory iodization of household salt with 30 mg KI/kg, was introduced. Based on multiple surveys it was found that the model of prophylaxis employed in Poland has proved to be effective. Thus, Poland became a country with sufficient iodine supplementation on the population level. The prevention and control of iodine deficiency is a continuous process. It requires monitoring to be sustainable. There are many examples throughout the world where iodine deficiency has re-emerged as a public health problem, where once it was under control. The aim of the study was to track the changes in iodine supply in recent years. School-age children were examined in 3 subsequent time points – in 1994, before establishment of iodine prophylaxis, in 1999 – 2 years after implementation of prophylaxis and in 2010 – 14 years after its implementation. 104 children (54 girls and 50 boys; age range from 6 to 15 years), 207 children (104 girls and 103 boys; age range from 7 to 15 years), and 174 children (94 girls and 80 boys; age range from 8 to 15 years) were examined in 1994, 1999 and 2010, respectively. A significant increase in iodine excretion was observed, together with the decrease in goitre incidence and thyroid size. The median of UICs was 45.5 µg/l (1994), 101.1 µg/l (1999) and 100.6 µg/l (2010). Data demonstrate not only the effectiveness of iodine prophylaxis but also homogenous iodine intake in 2010 in comparison to year 1999, as the percentage of children in whom UIC was less than 50 µg/l decreased from 12.6 (1999) to 7.1% (2010). It seems that at present the biggest problem is to define the reference values of thyroid volume, because values proposed by Zimmermann et al, which are currently being applied, still indicate the presence of goitre endemicity in Poland (15-18%). Looking for a better tool to analyze the size of the thyroid gland, the results of thyroid volume (V) were compared to the body surface area (BSA) to give the ratio V/BSA. In our opinion, this ratio (V/BSA) better reflects changes in thyroid volume in particular time points and may be useful tool for comparing the size of the thyroid in different populations. Fifteen years after the implementation of iodine prophylaxis in Poland the iodine intake has not only increased, but it is also more homogeneous. However, these values still oscillate around the lower values of normal range, which must be a cause for further concern as the widely recommended restriction of salt intake in everyday diet can lead to a decline in iodine intake below the recommended values.

Doubts and Concerns about Isolated Maternal Hypothyroxinemia

There is evidence that isolated maternal hypothyroxinemia may have detrimental effects on both mother and foetus. Nonetheless, this condition is still far from being universally accepted as a separate thyroid disease, and a standard definition of this state of mild thyroid underfunction is still lacking. We will review the biochemical criteria used to define isolated maternal hypothyroxinemia, together with current methodological issues related to FT4 assays. We will also discuss its epidemiological impact in both iodine-deficient and-sufficient areas, and the effectiveness of iodine prophylaxis on maternal thyroid function and neuropsychomotor development in offspring.

Assessment of iodine availability and its influence on hematological characteristics of iodine prophylaxis in pregnant women living in the iodine deficient natural environment

The objective of the present study was to evaluate effects of iron deficiency anemia in pregnant women on the effectiveness of iodine prophylaxis; the secondary objective was to develop standard prophylactic iodine dose schedule for these patients. The study included two groups of pregnant women treated either with a daily dose of 200 mcg potassium iodide (group 1, n=32) or with 300 mcg potassium iodide/day (group 2, n=68). In all of them, blood TSH, free thyroxin and antithyroid peroxidase antibody levels were measured along with iodine excretion in urine. Thyroid volume was determined by ultrasound. Diagnosis of anemia was based on the results of clinical blood analysis including hemoglobin level, erythrocyte count, hematocrit, and mean hemoglobin content of red blood cells. Iron deficiency was estimated from serum iron and ferritin (SF) levels. Treatment with potassium iodide during pregnancy resulted in a significant increase of the median urine iodine level to 260.9 mcg/l and 143.7 mcg/l in groups 1 and 2 respectively (p<0.05). It means that iodine excretion in urine during pregnancy is directly related to the efficiency of prophylaxis; it is optimal in women consuming daily at least 300 mcg of potassium iodide. Of all hematological parameters, the serum ferritin level undergoes the largest deviation (decrease) from the normal value. It was below 15 ng/ml in 24 (31.2%) patients with the median urine iodine level of less than 150 mcg/l and in 10 (11.1%) patients with the median urine iodine level higher than 150 mcg/l (a three-fold difference).

Iodine prophylaxis—the protective factor against stomach cancer in iodine deficient areas

Poland has one of the highest death rates for stomach cancer in Europe. Moderate iodine deficiency and in consequence high goitre prevalence led to the implementation in 1996 of a very efficient mandatory model of iodine prophylaxis, based on household salt iodisation (30 +/- 10 mg KI/1 kg of salt). The aim of the study was evaluation of incidence rate of stomach cancer and its possible relation to increased iodine consumption in the years 1992-2004. Iodine supply and effectiveness of iodine prophylaxis were evaluated on the basis of comparative analysis of goitre prevalence and ioduria in schoolchildren. To allow comparison between time periods with varying population age structures, the incidence rates of stomach cancer were standardized for age, using the "world standard population". The direct standardization method has been applied. For each sex, the time-trend of incidence rates was shown in graphs over the years 1991-2004. Evident increase in iodine consumption in this period of time was proved by rise in percentage of schoolchildren (6-8 years old) with ioduria above 100 microg/l from 11.4% in 1992-1993 to 52.9.1% in 2003. It was correlated with the decrease in goitre prevalence from 18.8% to 3.2% respectively. The 24-h thyroid uptake of (131)I in investigated population fell from 45.5% in 1986 to 26.8% in 1998. In Krakow the standardized incidence ratio of stomach cancer for men decreased from 19.1 per 100,000 to 15.7 per 100,000, and for women from 8.3 per 100,000 to 5.9 per 100,000 in the years 1992-2004. A significant decline of average rate of decrease was observed in men and women (2.3% and 4.0% per year respectively). Observed association between improved iodine supply and decrease of incidence of stomach cancer could indicate the protective role against stomach cancer of iodine prophylaxis in iodine deficient areas--further studies are necessary.

The effectiveness of iodine prophylaxis when delayed: implications for emergency planning

Emergency plans for accidents involving releases of radioiodine often include adminstering stable iodine as a countermeasure. If taken shortly before, or at the same time as, exposure to airborne radioiodine, this almost completely blocks the uptake of radioiodine by the thyroid. However, if the tablets are not taken until some hours after exposure, the protection will be reduced. This paper reviews one major factor affecting the rate at which the effectiveness is reduced: the rate at which iodine is taken up by the thyroid after it reaches the bloodstream, and the variations in this rate between individuals. An important finding is that for a substantial fraction of the population the rate of uptake may be greater than implied in some publications. However, the effectiveness of stable iodine as a countermeasure is also influenced by other factors, such as the duration of the release. These factors are also discussed, together with the overall implications for emergency planning.