Iodine deficiency in Calabria: characterization of endemic goiter and analysis of different indicators of iodine status region-wide

[Critical analysis of the indicators of the nutritional status of iodine in individuals and populations: a systematic review]

The scope of this article is to evaluate the potentialities of indicators of the nutritional status of iodine in individuals or populations. The review was based on PRISMA. The search for articles occurred in January 2019, in the Pubmed, Scopus and LILACS databases, using the key words: indicators AND nutritional status AND iodine. The selection followed the stages of excluding the duplicates, reading the titles, abstracts and analyses in full. The methodological quality of the studies was evaluated by the Downs and Black instrument. A total of 178 studies were identified and 20 were included. Urinary Iodine Concentration (UIC) was analyzed in 65% of the studies and was considered the best indicator to evaluate the nutritional status of iodine in the population. Thyroglobulin was determined in 20% of the studies and reflected the pre-existing state of iodine. Thyroid stimulating hormone was verified in 45% of the articles and was important for the surveillance of iodine deficiency among newborns. Only one study evaluated capillary iodine, useful for analyzing long-term dietary intake. In the evaluation of methodological quality, the lowest score was 12 and the highest 16, in 17 possible points. The use of UIC is recommended for the diagnosis of deficiency and excess of iodine in the population.

Endemic Goiter and Iodine Prophylaxis in Calabria, a Region of Southern Italy: Past and Present

Iodine, a micronutrient that plays a pivotal role in thyroid hormone synthesis, is essential for proper health at all life stages. Indeed, an insufficient iodine intake may determine a thyroid dysfunction also with goiter, or it may be associated to clinical features such as stunted growth and mental retardation, referred as iodine deficiency disorders (IDDs). Iodine deficiency still remains an important public health problem in many countries, including Italy. The effective strategy for the prevention and control of IDDs is universal salt iodization, which was implemented in Italy in 2005 as a nationwide program adopted after the approval of an Italian law. Despite an improvement in the iodine intake, many regions in Italy are still characterized by mild iodine deficiency. In this review, we provide an overview of the historical evolution of the iodine status in the Calabria region, located in the South of Italy, during the past three decades. In particular, we have retraced an itinerary from the first epidemiological surveys at the end of the 1980s to the establishment of the Regional Observatory of Endemic Goiter and Iodine Prophylaxis, which represents an efficient model for the surveillance of IDDs and monitoring the efficacy of iodine prophylaxis.

Agreement between markers of population iodine status in classifying iodine status of populations: a systematic review

BACKGROUND

Population iodine deficiency is indicated by >3% of the population with newborn thyroid-stimulating hormone (TSH) concentration >5 mIU/L, median urinary iodine concentration (MUIC) <100 µg/L, or >5% prevalence of goiter in school-age children. However, the agreement between these population markers has not been systematically investigated.

OBJECTIVE

To assess the agreement between TSH, MUIC, and goiter as markers of population iodine status.

METHODS

We performed a systematic search for studies published on PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, and PsycINFO up to 29 October, 2018. Studies assessing iodine status in the population using the TSH marker and either MUIC or goiter prevalence in school-age children were included. The agreement between markers in classifying iodine status of the population was assessed. The sensitivity and specificity of the TSH marker was determined against MUIC and goiter prevalence as the reference markers.

RESULTS

Of 17,435 records identified by the search strategy, 57 eligible studies were included in the review. The agreement between markers in classifying the iodine status of populations into the same category was 65% for TSH and MUIC, and 83% for TSH and goiter prevalence. The TSH marker had a sensitivity of 0.75 and specificity of 0.53 when compared with MUIC, and 0.86 and 0.50 when compared with goiter prevalence.

CONCLUSIONS

The TSH marker has a better agreement with goiter prevalence than MUIC when classifying the iodine status of populations. Re-evaluation of the current criteria for classifying the iodine status of populations using the TSH marker is warranted. This systematic review was registered at PROSPERO (http://www.crd.york.ac.uk/prospero/) as CRD42018091247.

Iodine status and characteristics of Korean adolescents and their parents based on urinary iodine concentration: a nationwide cross-sectional study

PURPOSE

Iodine is a major component of thyroid hormones. Both deficiency and excess of iodine are major risk factors for thyroid disease, making it important to accurately assess iodine level in the human body. Urinary iodine concentration (UIC) is a commonly used measure of iodine status. However, there is little research on iodine status and related characteristics in Korean adolescents.

METHODS

Using data from the sixth Korea National Health and Nutrition Examination Survey (KNHANES VI) for the years 2013-2015, we analyzed UIC and thyroid function test results in adolescents aged 10-18 years and their parents. We also investigated the influence of socioeconomic factors and family history of thyroid disease on iodine status.

RESULTS

Mean UIC in Korean adolescents was 963.5±55.7 μg/L. Among evaluated subjects, 6.6%±1.0%, 29.8%±1.7%, and 63.9%±1.9% had low (UIC&lt;100 μg/L), adequate (UIC: 100-299.9 μg/L), and excess (UIC≥300 μg/L) iodine concentrations, respectively. Based on regional trends, the incidence of iodine deficiency exceeded 10% in several regions, even though there was a dominance of regions with excess iodine. Parental UIC, female sex, average monthly income, and expenditure were all found to affect the iodine status of Korean adolescents.

CONCLUSION

Although regional differences exist, the iodine status in Korean adolescents is mainly affected by the eating habits of their families and socioeconomic factors. Therefore, monitoring of iodine status is necessary in this population.

The geographical pattern of thyroid cancer mortality between 1980 and 2009 in Italy

BACKGROUND

Mortality for thyroid cancer (TC) is low and has been decreasing worldwide; yet few population studies based on mortality have been conducted. Several nonradiation risk factors have been associated with TC, including residence in goiter-endemic areas (as an indicator of iodine deficiency). We used mortality data to perform a spatial-temporal analysis regarding TC in Italy and investigated the association between mortality and socioeconomic status and geographical features (residing in a mountainous area is a proxy for iodine deficiency).

METHODS

We analyzed data from Italy's National Mortality Database (1980-2009). To evaluate temporal trends in mortality the age-standardized death rate (ASR) was used; to identify geographic areas with excess deaths due to TC standardized mortality rates (SMR) were calculated. We also calculated the rate ratios (RR) of the ASR and the 95% CI by sex. We performed a cluster analysis to identify municipalities with major departures from expected mortality, both in the entire study period and in two separate periods to evaluate the spatial-temporal variability. Finally, we evaluated the association between mortality and index of deprivation and altitude.

RESULTS

There were 16,473 deaths due to TC (10,690 females, 5783 males). The mean ASR was unsurprisingly low (0.58/100.000). There was a trend of decrease in mortality throughout Italy (-42% for 2007-2009 vs. 1980-1984), more pronounced among women. The decrease was greater in the north. Four geographic clusters were identified when considering the entire study period, two in the north and two in the south; however, the clusters in northern Italy refer to the earlier period (1980-1994) and those in southern Italy to the later period (1995-2009). Mortality was associated with residing in a mountainous area. A slight association with high socioeconomic status was found.

CONCLUSIONS

This study reveals space-time differences in TC mortality in Italy. It shows an association between mortality and residing in mountainous areas, which is a proxy of iodine deficiency. The observed temporal north-south shift cannot be explained by socioeconomic differences, whereas the efficient prophylaxis program implemented in the 1980s in some areas of northern Italy can help to explain the disappearance of the clusters in those areas in the period 1995-2009.

Relationship between metabolic syndrome and multinodular non-toxic goiter in an inpatient population from a geographic area with moderate iodine deficiency

BACKGROUND

Obesity and insulin resistance predispose individuals to the development of both metabolic syndrome and non-toxic nodular thyroid diseases.

AIM

The aim of this observational, cross-sectional study is to evaluate the relationship between metabolic syndrome and multinodular nontoxic goiter in an inpatient population from a geographic area with moderate iodine deficiency.

SUBJECTS AND METHODS

We examined 1422 Caucasian euthyroid inpatients. Thyroid volume was determined by ultrasound of the neck. A fine-needle aspiration biopsy was performed to evaluate single thyroid nodules and dominant nodules ≥15 mm in euthyroid multinodular goiter. The diagnosis of metabolic syndrome was made according to the criteria of the American Heart Association/ National Heart, Lung, and Blood Institute.

RESULTS

Of the sample, 277 patients had clinical evidence of multinodular nontoxic goiter, 461 met the criteria for the diagnosis of metabolic syndrome, and 132 were found to have both conditions. After adjusting for age, gender, body mass index, nicotinism, parity, alcohol intake, thyroid function, and metabolic syndrome- related pharmacological treatment, metabolic syndrome was found to be an independent risk factor for the occurrence of multinodular non-toxic goiter. The relationship between metabolic syndrome and multi nodular non-toxic goiter was apparent in both men and women.

CONCLUSIONS

In this study of euthyroid inpatients, we demonstrate that metabolic syndrome is an independent risk factor for the occurrence of multinodular non-toxic goiter in a geographic area with moderate iodine deficiency. We propose that patients meeting the criteria for metabolic syndrome should be screened for the presence of multinodular non-toxic goiter.

Beneficial effects of iodized salt prophylaxis on thyroid volume in an iodine deficient area of southern Italy

OBJECTIVE AND SUBJECTS

Goitre prevalence in school-age children is an indicator of the severity of iodine deficiency disorders (IDD) in an endemic area. The aims of the present study were (i) to provide ultrasound thyroid volume (TV) reference values in a healthy population of school-children aged 11-14 year living in iodine-sufficient areas of Calabria region (ii) to assess both goitre prevalence and urinary iodine (UI) concentration in all children aged 11-14 year from four mildly iodine-deficient areas in which we have carried out a program of salt iodization and (iii) to evaluate the efficacy of the iodoprophylaxis in an adult population living in a small village of the same endemic area.

DESIGN

Cross-sectional and prospective studies.

METHODS

TV was assessed by ultrasonography and iodine intake was estimated by measuring iodine excretion in spot urine samples. Results We provided the ultrasound normal reference values as a function of age and body surface area, which displayed significant differences from those recommended by the World Health Organization. By adopting local criteria, the prevalence of goitre in children ranged from 23.4% to 27.7% normalized for age and body surface area, respectively, while the UI excretion was < 100 microg/l in 38% of subjects studied. In an adult population living in the same endemic area, goitre prevalence was lowest in the 18-27-year-old age group, and increased progressively with age.

CONCLUSION

We propose for the first time local reference ultrasound values for TV in a population of 11-14-year-old school-children that should be used for monitoring IDDs and have demonstrated the beneficial effects of iodoprophylaxis in consistent with reduced goitre prevalence in children and in the young adult population studied.

Changed presentation of Hashimoto's thyroiditis in North-Eastern Sicily and Calabria (Southern Italy) based on a 31-year experience

OBJECTIVE

To quantify the yearly prevalence of Hashimoto's thyroiditis at our Division and evaluate changes in its clinical presentation over the period 1975-2005.

DESIGN

We have reviewed retrospectively the clinical records of patients admitted to a university hospital located in Messina, Sicily (Italy), from January 1, 1975, through December 31, 2005. This facility attracts patients from North-Eastern Sicily and most of Calabria, the Italian region across the Straits. HT was diagnosed based on various combinations of clinical, laboratory, and instrumental findings. The study group consisted of 4064 HT patients diagnosed during these 31 years.

MAIN OUTCOME

We evaluated these indexes on a yearly basis: number of new HT diagnoses; age at presentation; male-to-female ratio; functional status; goitrous or nongoitrous variants with or without nodule(s); above-normal titers or levels of serum thyroid autoantibodies (thyroglobulin antibodies and thyroperoxidase antibodies). Several indexes have changed over those 31 years. Particularly, HT has become 10 times more common than it was until the early 1990s and males are relatively more represented. Patients are relatively younger, with a nongoitrous thyroid; the rate of S-Hypo exceeds largely the rate of O-Hypo. Serum thyroid autoantibodies have become less frequently positive, and when positive, they are present at a lower concentration.

CONCLUSIONS

Only environmental changes, as opposed to genetic changes, can account for such alterations in the presentation of HT in our geographical area.

hNIS protein in thyroid: the iodine supply influences its expression and localization

OBJECTIVE

Nonfunctioning thyroid nodules (NFTNs) display a diminished iodide-concentrating ability, owing to defective expression and cell membrane targeting of the sodium-iodide symporter (NIS). Since NIS expression is primarily modulated by thyroid iodine content in vitro and in animal models, we attempted to determine whether iodine supply influences the expression and localization of human NIS (hNIS) in NFTNs.

DESIGN

Using immunohistochemistry, we analyzed cold hyperplastic nodules and nonnodular thyroid samples (controls) from patients living in iodine-sufficient (n = 19) or severely iodine-deficient (n = 15) areas.

MAIN OUTCOME

Nodules from the iodine-sufficient area exhibited weak or absent hNIS immunostaining whereas almost all nodules from the iodine-deficient area were hNIS positive. Heterogeneous hNIS staining was common among the iodine-deficient samples (p = 0.028). hNIS was localized on membrane in all nodular samples from the iodine-deficient area and in less than 40% in the iodine-sufficient area.

CONCLUSIONS

hNIS is adequately expressed and appropriately localized in NFTNs cell membrane from iodine-deficient areas and its expression in vivo is modulated by iodine supply.

Predictive value of serum calcitonin levels for preoperative diagnosis of medullary thyroid carcinoma in a cohort of 5817 consecutive patients with thyroid nodules

CONTEXT

Routine serum calcitonin (CT) measurement in patients with thyroid nodules for diagnosis of medullary thyroid carcinoma (MTC) is controversial.

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of systematic CT measurement in non-multiple endocrine neoplasia type 2 patients with nodular thyroid disease.

SETTINGS

This study was conducted at a national healthcare system hospital (outpatient and inpatient sectors).

SUBJECTS

Consecutive patients with nodular thyroid disease (n = 5817) were studied.

MAIN OUTCOME MEASURES

Serum CT levels were measured under basal conditions, and when basal values were more than or equal to 20 and less than 100 pg/ml, testing was repeated after pentagastrin stimulation. Basal or stimulated levels more than 100 pg/ml were indication for surgery.

RESULTS

Fifteen cases of MTC and seven of C cell hyperplasia (CCH) were identified. MTCs were diagnosed in all patients with basal CT more than 100 pg/ml. The four patients with basal CT more than or equal to 50 and less than 100 pg/ml included two diagnosed with MTC and two with CCH. In 10 patients with basal levels more than or equal to 20 and less than 50 pg/ml, histology confirmed the presence of MTC in four, four others had CCH, and the remaining two were negative for thyroid malignancy. Positive predictive values for basal CT levels in the preoperative diagnosis of MTC were: 23.1% for values more than or equal to 20 pg/ml, 100% for values more than 100 pg/ml, 25% for levels more than or equal to 50 and less than 100 pg/ml, and 8.3% for values more than or equal to 20 and less than 50 pg/ml. Positive predictive values for the pentagastrin test (>100 pg/ml) were 40% in the entire series.

CONCLUSIONS

CT screening of thyroid nodules is a highly sensitive test for early diagnosis of MTC, but confirmatory stimulation testing is necessary in most cases to identify true positive increases.

Incidental Thyroid Carcinoma in Thyrotoxic Patients Treated by Surgery

BACKGROUND AND AIMS

Thyroid malignancy detected incidentally in patients who are operated for thyrotoxicosis has been reported at different rates. The aim of this study was to investigate the rate of incidental thyroid carcinoma in thyrotoxic patients managed with surgery in our institution.

METHODS

Of the 375 thyrotoxic patients who had thyroid surgery between the years of 1997-2004, 70.7% were females and 29.3% were males. Among thyrotoxic patients 65.3% (n=245) had toxic multinodular goiter (TMG), 16.8% (n=63) had toxic adenoma (TA) and 17.9% (n=67) had Graves' disease.

RESULTS

Twenty-six (6.9%) of all thyrotoxic patients had thyroid carcinoma. Eighteen (7.3%) of TMG, 4 (6.3%) of TA and 4 (6%) of Graves' disease patients had thyroid carcinoma. Histologic examination revealed 18 papillary (9 microscopic), 5 follicular, 2 hurthle cell and 1 anaplastic carcinoma.

CONCLUSION

In our study, incidental thyroid carcinoma was found in 6.9% of subjects with thyrotoxicosis. Papillary thyroid microcarcinomas constituted 34.6% (26/9) of these newly diagnosed thyroid carcinomas. The incidence of thyroid carcinoma was not higher in subjects with Graves' disease compared to TMG and TA. The rate of incidental thyroid carcinoma in subjects with thyrotoxicosis treated with surgery was similar to previous studies reported from different countries.

Slow growth of benign thyroid nodules after menopause: no need for long-term thyroxine suppressive therapy in post-menopausal women

Benign thyroid nodules represent a very common disorder, the management of which is still controversial. The aim of the present work was to evaluate by ultrasound examination the volume changes of thyroid nodules in post-menopausal women presenting single palpable nodular goiter of recent onset (less than 6 months from diagnosis). Forty-three patients received L-T4-treatment, 38 represented the no-treatment group. Long-term follow up (3 and 5 yr) did not show any significant change in the mean volume nodule in these patients. In the no-treatment group, the mean nodule volumes were stable over time from baseline to 5 yr. No significant difference was observed at any follow-up evaluation between thyroid hormone treated and untreated patients. After 1 yr of treatment, a significant decrease (p = 0.0275) in mean nodule volume occurred only for nodules with a baseline volume lower than 1.5 ml. The frequency of clinically relevant nodule size variation showed a more frequent decrease (13.9%) at 1 yr in the L-T4 group, as compared to the no-treatment group (2.6%), while the proportion of increased volume at 1 yr was higher in the untreated than in the L-T4 group (5.3% vs 2.3%). This inverse relationship between the 2 groups was not statistically significant (p = 0.076). In conclusion, an arrest in the growth of benign thyroid nodules occurs in the majority of women after menopause. Only a very limited number of these patients may benefit from thyroid hormone suppressive treatment.

Spot urinary iodine concentration as a measure of dietary iodine, evaluated in over 3800 young male subjects undergoing medical check-up preliminary to military enrolment in Piemonte and Aosta Valley (Italy)

The aim of the study was to assess iodine status in over 3800 young male subjects aged 18, living in 6 different provinces of Piemonte and in Aosta Valley, Italy. A cross-sectional study on 3837 young male subjects undergoing medical evaluation preliminary to military enrolment was performed. Spot urine samples were obtained in the morning hours and urinary iodine was measured by a colorimetric method. As outcome measure iodine status, based on spot urinary iodine median concentration, categorised as sufficient (>99 microg/l), mild deficiency (50-99 microg/l), moderate deficiency (20-49 microg/l) and severe deficiency (<20 microg/l), was obtained. Median urinary iodine concentration was 101.8 microg/l in our sample. Moderate-to-severe iodine deficiency was found in <10% of all subjects. Mild iodine deficiency was found in <40% of the subjects, with greater variability within the provinces considered. For each geographical area significant differences can be observed in more than 50% of the comparisons of the confidence intervals related to the frequencies of samples with spot urinary iodine concentration below 100 microg/l. The high frequency of mild iodine deficiency found in our sample suggests that dietary sources of iodine in Piemonte, Italy, have improved since the last evaluation 25 yr ago (2) but may still be insufficient. Further population studies are required.