Low socio-economic status and familial occurrence of goitre are associated with a high prevalence of goitre

Prevalence and determinants of goitre among children of South Kordofan state, Sudan, 2021: an urgent need for effective implementation of universal salt iodisation

OBJECTIVE

This study aimed to determine the prevalence and determinants of goitre among children aged 6-12 years at South Kordofan state.

DESIGN

This was a cross-sectional facility-based study.

SETTING

The study was conducted in twenty villages of South Kordofan state during a medical mission.

PARTICIPANTS

All 575 school-age children (6-12 years) who attended the medical day were examined for clinical assessment of goitre.

RESULTS

The prevalence of goitre among children of South Kordofan was 42·8 % (grade 1: 15·7 %, grade 2: 27·1 %). Only 24·2 % of caregivers reported using iodised salt. Mothers working as farmers (OR: 3·209, CI 95 % 1·437, 7·167; P = 0·004) and children of Darforian tribes (OR: 21·799, CI 95 % 2·566, 185·226; P = 0·005) were found to be significantly associated with higher prevalence of goitre among children. This contrasts with children of African tribes, where they were found to have less goitre prevalence (OR: 0·432, CI 95 % 0·213, 0·875; P = 0·02). Iodised salt utilisation (OR = 0·523, CI 95 % 0·320, 0·854; P = 0·01) was found associated with a lower prevalence of goitre.

CONCLUSION

Even though National Iodine Deficiency Disorders control programs were initiated in Sudan more than 25 years ago, the prevalence of goitre among children in South Kordofan state was alarming (42·8 %). Efforts to improve access to iodised salt, increase utilisation and raise awareness are urgently needed.

Breast cancer, breast cancer-directed radiation therapy and risk of hypothyroidism: A systematic review and meta-analysis

OBJECTIVE

Breast cancer and breast cancer-directed radiation therapy (RT) may increase the risk of late effects, such as hypothyroidism. We conducted a systematic review and meta-analysis to investigate the association between breast cancer, RT, and risk of hypothyroidism in breast cancer survivors.

METHODS

Through February 2022, we searched PubMed, EMBASE, and references of relevant articles, to identify papers on breast cancer and breast cancer-directed RT and subsequent risk of hypothyroidism. Articles were screened by title and abstract and reviewed for eligibility. We used a pre-formed data extraction sheet and identified key design elements that could potentially introduce bias. The main outcome was the confounder-adjusted relative risk (RR) of hypothyroidism in breast cancer survivors versus women without breast cancer, and in breast cancer survivors according to the receipt of RT to the supraclavicular lymph nodes. We used a random-effects model to calculate pooled RRs and associated 95% confidence intervals (95% CI).

RESULTS

From 951 papers screened by title and abstract, 34 full-text papers were reviewed for eligibility. We included 20 studies published between 1985 and 2021-19 were cohort studies. Compared with women without breast cancer, the pooled RR of hypothyroidism in breast cancer survivors was 1.48 (95% CI: 1.17, 1.87), with highest risk associated with RT to the supraclavicular region (RR = 1.69, 95% CI: 1.16, 2.46). The most important limitations of the studies were small sample size yielding estimates with low precision, and lack of data on potential confounders.

CONCLUSION

Breast cancer and radiation therapy to the supraclavicular lymph nodes is associated with an increased risk of hypothyroidism.

Higher free thyroxine associated with PFAS exposure in first trimester. The Odense Child Cohort

BACKGROUND

Perfluoroalkyl substances (PFAS) are endocrine disrupting chemicals with elimination half-lives ranging from four to eight years. Experimental studies found PFAS able to interfere with thyroid hormone-binding proteins. During the first 20 weeks of gestation (GW), the fetus is reliant on placental transfer of maternal thyroid hormones, mainly free thyroxine (FT4). However, previous studies investigating associations between exposure to PFAS and thyroid hormone status mainly focused on blood samples from late pregnancy or umbilical cord with mixed findings.

OBJECTIVES

To investigate associations between serum-PFAS concentrations and thyroid hormone status in early pregnancy as reflected by FT4 and thyroid-stimulating hormone (TSH).

METHODS

In the Odense Child Cohort, a single-center study, we measured maternal pregnancy serum concentrations of five PFAS: perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA); and FT4 and TSH in 1048 pregnant women at median GW 12 (25th, 75th percentile: 10, 15). Multivariate linear regression models were performed to estimate associations between PFAS exposure and thyroid hormone status.

RESULTS

A doubling in PFOS, PFOA, and PFNA concentrations was associated with an increment in FT4 concentration by 1.85% (95% CI: 0.66%, 3.05%), 1.29% (95% CI: 0.21%, 2.39%), and 1.70% (95% CI: 0.48%, 2.94%), respectively, in adjusted analyses. A statistically significant dose-response relationship was observed across exposure quartiles for PFOS, PFOA, and PFNA in the association with FT4. No association was found between concentrations of PFAS and TSH in adjusted analyses.

CONCLUSION

Exposure to PFOS, PFOA, and PFNA was associated with higher FT4 concentrations in women during early pregnancy. The potential clinical implications of these findings remain to be clarified.

The prevalence of thyroid nodules and its factors among Chinese adult women: A cross-sectional study

OBJECTIVE

To determine the prevalence of thyroid nodules in Chinese adult women. To analyze the relationships between lifestyle, metabolic syndrome and thyroid nodules.

METHODS

We conducted a retrospective cross-sectional study in the tertiary hospital from 2017 to 2019. Included participants underwent thyroid color Doppler ultrasonography, lipids examination, and dietary evaluation.

RESULTS

Totally 2,784 participants were included, and 933 participants were found to have thyroid nodule(s) by B-ultrasound. The prevalence of thyroid nodules was 33.3%. Women in 50-59 years (OR: 1.746, 95% CI [1.356-2.249]), older than 60 (2.147 [1.540-2.993]) and occupations with mainly manual work (1.780 [1.367-2.317]) were risk factors for thyroid nodules, while moderate dietary diversity (0.624 [0.476-0.817]) and normal triglycerides level (0.739 [0.604-0.905]) were protective factors.

CONCLUSION

Women over 50 and those whose jobs are mainly manual should enhance screening, follow-up and health management of thyroid nodules. Higher dietary diversity is protective measures against thyroid nodules for adult women and should consider dietary balance and the food varieties, not just increased quantities.

Prevalence of iodine deficiency among pregnant women in Gwembe and Sinazongwe districts of Southern Province, Zambia: a cross-sectional study

Background

Maternal iodine deficiency is one of the common causes of morbidity and mortality during pregnancy. Maternal iodine deficiency during pregnancy is associated with a number of adverse outcomes such as abortion, stillbirth, congenital anomalies, perinatal mortality and irreversible mental retardation. A study conducted in Zambia among pregnant women in 2013 on the prevalence of iodine deficiency showed that iodine deficiency was not a public health concern. The previous study used Urine Iodine concentration (UIC) as a marker of iodine deficiency among the pregnant women. Our study was conducted to assess the prevalence of iodine deficiency among pregnant women in Gwembe and Sinazongwe districts of Southern Province, Zambia, using urine iodine concentration and goitre presence by manual palpation.

Methods

We carried out a community based, cross sectional study in rural areas of Gwembe and Sinazongwe districts between April 2016 to March 2018. Data were collected from 412 pregnant women by a multistage cluster sampling technique. The presence of a goitre was examined by manual palpation and urinary iodine concentration was determined by the Ultra Violet Method using PerkinElmer Labda UV Spectrometer equipment made in Jena Germany (Model 107,745). As part of the existing baseline data, we used results of a 2013 countrywide study (n = 489) for household salt iodine content which showed a greater than 40 ppm at 76.2%, between 15 and 40 ppm at 19.21% and less than 15 ppm at 4.59%. Statistical analysis was done using Stata version 14.0. The outputs of analysis are presented as median and Interquartile range (IQR) as the urine data were not normally distributed. Further, the categorical and independent variables were presented as proportions (percentages) to describe the distribution and trends in the target sample population.

Results

The median Urine Iodine concentration (UIC) of the pregnant women was 150 μg/L (Interquartile Range (IQR): 100–200 μg/L). Based on the UIC, There were 49% pregnant women who had inadequate iodine intake with urine iodine concentration of less than 150 μg/L, 34.0% had UIC of 150–249 μg/L indicating adequate iodine intake, 13.0% with UIC of 250–499 μg/L indicating more than adequate iodine intake, and 5.0% with UIC of above 500 μg/L indicating excessive iodine intake. To determine whether the women had access to iodized salt, we used baseline data from 2013 Zambia national survey for iodine concentration in household salt samples as being an average of 40 ppm, which also showed that 95.41% households consumed adequately iodized salt (≥15 ppm). The prevalence of goitre in our study was very low at 0.02% among the pregnant women of all ages who participated in the study (18–49 years).

Conclusion

Iodine deficiency was still not a public health concern among the pregnant women of Gwembe and Sinazongwe districts of Southern Province in Zambia. Goitre prevalence has remained very low in this study area. The UIC and goitre observations were consistent with the Zambia National Food and Nutrition Commission findings in 2013 report. However, our study showed more pregnant women with insufficient than adequate iodine status indicating the risk of developing IDD is still high in this region. It also reinforces the argument that strengthening of the existing salt iodization program is needed in order to make a homogenous iodated salt available to the communities. The National Food and Nutrition Commission of Zambia needs to find innovative ways of sensitizing people about the adverse effects of IDDs and how these could be prevented. It is recommended that iodine supplementation be introduced as part of the package of Antenatal clinic care for all pregnant women.

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<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.

Socioeconomic disparities in a population of patients undergoing total thyroidectomy for benign disease

BACKGROUND

This study examines the effect of insurance status (as a measure of socioeconomic status) on patient with benign thyroid disease.

METHODS

A retrospective review was performed among 60 patients undergoing total thyroidectomy for benign thyroid disease. Univariate and multivariable analyses examined the relationship between insurance status and thyroid volume (sum of the left and right lobe volumes).

RESULTS

Twenty-eight (47%) patients were considered of underinsured/uninsured status, and 32 (53%) patients were considered of private/government/military insurance status. Median pathologic whole thyroid volume was 66 mL (range, 2-855). After multivariable linear regression, underinsured/uninsured status was the only significant predictor of larger volume (correlation coefficient [r] = 118; 95% CI, 42 to 194; P = .003), after adjusting for age, sex, body mass index, and presence of concomitant thyroid disease and compressive symptoms.

CONCLUSION

Patients of underinsured/uninsured status suffered more severe disease presentations at time of thyroidectomy, as measured by larger thyroid volumes.

Prevalence of iodine deficiency and associated factors among pregnant women in Ada district, Oromia region, Ethiopia: a cross- sectional study

BACKGROUND

Maternal iodine deficiency (ID) during pregnancy has been recognized as a major cause of abortion, stillbirth, congenital abnormalities, perinatal mortality and irreversible mental retardation. In Ethiopia limited information is available regarding the epidemiology of maternal ID. The purpose of the present study was to assess the prevalence of iodine deficiency and associated factors among pregnant women in Ada district, Oromia region, Ethiopia.

METHOD

A community based, cross-sectional study was conducted in rural areas of Ada district, October to November, 2014. Data were collected from 356 pregnant women selected by multistage cluster sampling technique. Presence of goiter was examined by palpation and urinary iodine concentration was measured using inductively-coupled-plasma mass spectrometry. Salt iodine concentration was determined using a digital electronic iodine checker. Statistical analysis was done primarily using binary logistic regression. The outputs of the analysis are presented using adjusted odds ratio (AOR) with the respective 95% confidence intervals (CI).

RESULTS

The median urinary iodine concentration (UIC) was 85.7 (interquartile range (IQR): 45.7-136) μg/L. Based on UIC, 77.6% (95% CI: 73.0-82.0%) of the study subjects had insufficient iodine intake (UIC < 150 μg/L). The goiter rate was 20.2% (95% CI: 16.0-24.0%). The median iodine concentration of the household salt samples was 12.2 (IQR: 6.9-23.8) ppm. Of the households, only 39.3% (95% CI: 34.0-44.0%) consumed adequately iodized salt (≥15 ppm). Prevalence of goiter was significantly higher among pregnant women aged 30-44 years (AOR = 2.32 (95% CI: 1.05-5.14)) than among younger women and among illiterate women (AOR = 2.71 (95% CI: 1.54-4.79)). Compared to nulliparous, women with parity of 1, 2 and 3 or more had 2.28 (95% CI: 1.01-5.16), 2.81 (95% CI: 1.17-6.74) and 4.41 (95% CI: 1.58-12.26) times higher risk of goiter.

CONCLUSION

Iodine deficiency was a public health problem in the study area. This indicates the need for further strengthening of the existing salt iodization program in order to avail homogenously and adequately iodized salt. Also it is necessary to find ways to provide iodine supplements as needed until universal salt iodization (USI) is fully established.

The Prevalence of Thyroid Nodules and an Analysis of Related Lifestyle Factors in Beijing Communities

Thyroid nodules (TNs) have annual increasing trends worldwide, and large-scale investigations on the prevalence of TNs in Beijing communities have not been conducted since the introduction of salt iodization in 1995. We performed a cross-sectional study to determine the prevalence of TNs, their epidemiological characteristics, and their correlation with lifestyle factors. A total of 6324 permanent residents aged 18 years or older (mean age, 52.15 ± 11.58 years) from seven representative communities in Beijing were included in the analyses. Once informed consent was obtained, the subjects were asked to complete questionnaires, a physical examination, and thyroid ultrasound. A total of 3100 cases had TNs. The overall prevalence rate was 49.0%, and the age-standardized prevalence was 40.1%, which increased significantly as age increased (p < 0.001). The prevalence was significantly higher in females compared to males (p < 0.001), and it was significantly higher among female current smokers and former smokers compared to non-smokers (p = 0.007). There was no correlation between alcohol consumption and TNs, and there were no significant differences in the prevalence among different groups of taste preference. The prevalence decreased with an increased frequency of seafood intake (p = 0.015) and with higher literacy levels (p < 0.001). The Cochran-Armitage trend test showed that the prevalence significantly increased with decreased physical labor and exercise intensity (p < 0.001, p = 0.009). Logistic regression analysis showed that age (Odds ratio (OR) = 1.039 (1.034-1.044), p < 0.001), the female sex (OR = 1.789 (1.527-2.097)), Body mass index (BMI) (OR = 1.019 (1.005-1.034)), and current smoking habits (OR = 1.246 (1.046-1.483)) were independent risk factors for TNs. Our findings indicate that there is a high prevalence of TNs in Beijing, with a higher prevalence in females than in males. Moreover, the prevalence increases as age increases. Smoking and BMI are independent risk factors for TNs. Therefore, intervention against smoking and weight loss might help reduce the risk of TN occurrence.

Stress, relationship satisfaction, and health among African American women: Genetic moderation of effects

We examined whether romantic relationship satisfaction would serve as a link between early and later stressors which in turn would influence the thyroid function index (TFI), an indicator of physiological stress response. Using the framework of genetic susceptibility theory combined with hypotheses derived from the vulnerability-stress-adaptation and stress-generation models, we tested whether the hypothesized mediational model would be conditioned by 5-HTTLPR genotype, with greater effects and stronger evidence of mediation among carriers of the "s" allele. In a sample of African American women in romantic relationships (n = 270), we found that 5-HTTLPR moderated each stage of the hypothesized mediational model in a "for better or for worse" manner. That is genetic polymorphisms function to exacerbate not only the detrimental impact of negative environments (i.e., "for worse effects") but also the beneficial impact of positive environments (i.e., "for better effects"). The effect of early stress on relationship satisfaction was greater among carriers of the "short" allele than among those who did not carry the short allele, and was significantly different in both the "for better" and "for worse" direction. Likewise, the effect of relationship satisfaction on later stressors was moderated in a "for better "or "for worse" manner. Finally, impact on physiological stress, indexed using TFI level, indicated that the impact of later stressors on TFI level was greater in the presence of the short allele, and also followed a "for better" or "for worse" pattern. As expected, the proposed mediational model provided a better fit for "s" allele carriers.

Lebanese children are iodine deficient and urinary sodium and fluoride excretion are weak positive predictors of urinary iodine

PURPOSE

To assess iodine and fluoride status among Lebanese children.

METHODS

A nationally representative cross-sectional study of 6- to 10-year-old schoolchildren was conducted using multistage cluster sampling. Spot urine samples were collected from 1403 children, and urinary iodine, fluoride, creatinine and sodium levels were measured. Salt samples from markets (n = 30) were tested for iodine concentration by titration.

RESULTS

Median urinary iodine concentration was 66.0 µg/l, indicating mild deficiency, and almost 75 % of Lebanese children had a urinary iodine concentration (UIC) <100 µg/l. UIC was higher among children from private schools and in areas of higher socioeconomic status. Most salt samples were fortified at levels far below the legislated requirement, and 56 % of samples contained less than 15 ppm iodine. Fluoride-to-creatinine ratio (F/Cr) was 0.250 (0.159-0.448) mg/g. There were weak positive correlations between UIC and urinary sodium (r ² = 0.039, P value <0.001) and UIC and urinary fluoride (r ² = 0.009, P value <0.001).

CONCLUSIONS

Lebanese elementary school children are iodine deficient due to inadequately iodized salt. The weak correlation between UIC and urinary sodium suggests most dietary iodine does not come from iodized salt. The poor correlation between UIC and urinary fluoride suggests that fluoride intake is not affecting iodine metabolism. Efforts are needed in Lebanon to improve industry compliance with salt fortification through improved monitoring and enforcement of legislation.

Radioiodine therapy increases the risk of cerebrovascular events in hyperthyroid and euthyroid patients

BACKGROUND AND OBJECTIVE

Hyperthyroid patients treated with radioiodine have increased morbidity and mortality from cerebrovascular events. This risk has until now has been attributed to the hyperthyroidism. However, radioiodine therapy of benign thyroid diseases exposes the carotid arteries to radiation and is capable of inducing atherosclerosis. The objective of the study was to elucidate whether ionizing radiation from radioiodine might contribute to cerebrovascular morbidity.

METHODS

In a retrospective register cohort study, 4000 hyperthyroid and 1022 euthyroid goitre patients treated with radioiodine between 1975 and 2008 were matched 1:4 on age and sex with random controls. The cohort was followed from the date of treatment until hospitalization due to cerebrovascular event, death, 20 years of follow-up or March 2013. Data were analyzed in competing risk models adjusting for age, sex, Charlson's comorbidity score, atrial fibrillation and previous cerebrovascular events.

RESULTS

Mean follow-up time was 11.5 years, mean age 61 years, with a total number of 3228 events. Comparing all radioiodine-treated patients with controls, the fully adjusted model showed increased risk of cerebrovascular events among all treated patients, hazard ratio (HR) 1.18 (95% CI 1.09-1.29). The risk was increased among hyperthyroid (HR 1.17; 95% CI 1.07-1.28) as well as euthyroid patients (HR 1.21; 95% CI 1.02-1.44).

CONCLUSIONS

We report an increased risk of cerebrovascular events in hyperthyroid as well as euthyroid patients treated with radioiodine for benign thyroid disorders. That these patient groups have similar risks suggests the possibility that radiation from radioiodine contributes to cerebrovascular morbidity via acceleration or initiation of atherosclerosis.

Current prevalence of goiter determined by ultrasonography and associated risk factors in a formerly iodine-deficient area of Turkey

The aim of this study was to determine the prevalence of goiter and related risk factors in an adult population in a formerly iodine-deficient area of Turkey. In this cross-sectional study, we enrolled 2,500 subjects (1,270 women and 1,230 men, aged over 20 years) by multistage sampling. Blood and urine specimens were collected for the assessment of thyroid function. Thyroid ultrasonography (USG) was performed to measure thyroid volume and evaluate nodules. The overall goiter prevalence was 26.5 % (28.4 % in women, 24.5 % in men, P < 0.05). Median thyroid volume was 15.59 mL (13.65 mL in women, 17.96 mL in men, P < 0.0001). Median urinary iodine was 122.79 μg/L. USG revealed thyroid nodules in 35.2 % of the subjects (38.4 % in women, 31.8 % in men, P < 0.005). Age group analysis revealed the lowest rate in the 20-29-year age group (12.5 %), which increased with age, reaching the highest level (38.4 %) in the 70+ years age group. The prevalence of goiter was negatively correlated with education level and positively correlated with body mass index (BMI) and positive family history. According to occupation, goiter prevalence was highest in farmers (35.3 %) and housewives (32.2 %). Despite a normal range of current urinary iodine excretion levels, prevalence of goiter in this adult population in a formerly iodine-deficient province of Turkey remained high, even about 10 years after salt iodine supplementation program introduction. In addition, the goiter prevalence was higher for female gender, advanced age, positive family history of goiter, low education level, and high BMI.

Genetic and non-iodine-related factors in the aetiology of nodular goitre

Genetic and a large number of environmental non-iodine-related factors play a role in the cause of nodular goitre. Most evidence for the influence of genetic and environmental factors in the cause of goitre is from cross-sectional, population-based studies. Only a few studies have included prospective data on risk factors for nodular goitre, although few prospective data are available on the effect of iodine and tobacco smoking on goitre development. Goitre is not one single phenotype. Many epidemiological studies do not distinguish diffuse from nodular goitre, as the investigated parameter is often thyroid volume or frequency with increased thyroid volume. Moreover, information on the presence and effect of gene-environment, gene-gene, and environment-environment effect modifications is limited. Thus, firm conclusions about the relative contributions and causality of the investigated risk factors should be made with caution. Smoking seems to be an established risk factor for nodular goitre, possibly with effect modification from iodine intake, as the risk associated with smoking is smaller or absent in areas with sufficient iodine intake. The use of oral contraceptives might have protective effects against goitre, and childbirth is an increased risk factor for goitre in areas with non-optimal iodine intake. Insulin resistance is a recently investigated risk factor, and the risk of goitre may be reversible with metformin treatment. Iodine remains the major environmental risk factor for nodular goitre.

Prevalence of unknown thyroid disorders in a Sardinian cohort

OBJECTIVE

To assess thyroid function, the presence of thyroid antibodies, as well as the presence of goiter and/or nodules in subjects without a prior diagnosis of thyroid disorders, in a region with mild to moderate iodine deficiency.

DESIGN AND METHODS

This cross-sectional study is based on data obtained from first and third visits of participants in the Sardinian survey. We performed two different analyses. In one, we assessed the prevalence of unknown thyroid dysfunctions among 6252 subjects who had a medical examination and blood collection for assays of thyrotropin, free thyroxine, and antibodies against thyroperoxidase (AbTPO) and against thyroglobulin (AbTG). In a second analysis, we evaluated the frequency of undiagnosed goiter and nodules among 3377 subjects who had a thyroid ultrasound scan. Subjects were excluded if they had a previous history of thyroid disorders or presence of goiter and/or nodules, or thyroid surgery, or if they were taking drugs that could impair thyroid function.

RESULTS

We found a low prevalence of overt thyroid dysfunction (hyperthyroidism 0.4% and hypothyroidism 0.7%). The rates of subclinical hypothyroidism and hyperthyroidism were 4.7 and 2.4% respectively. Almost 16% of participants were positive for at least one antibody and 5.2% for both AbTG and AbTPO. Nodules were detected in 17.4% of subjects and the prevalence of goiter was 22.1%.

CONCLUSIONS

Undiagnosed biochemical thyroid dysfunctions, unknown nodules, and goiter were common in subjects living in a mild to moderate iodine-deficient area. In this community, thyroid disorders often go undetected and screening could be reasonable in subjects at a higher risk.

Iodine nutritional status and risk factors for goitre among schoolchildren in South Tajikistan

BACKGROUND

Iodine deficiency affects nearly 1.9 billion people worldwide, but it can be prevented by salt iodization. This cross-sectional survey assessed current iodine status, iodized salt coverage and risk factors for goitre among schoolchildren in South Tajikistan.

METHODS

Ten primary schools in four districts in South Tajikistan were randomly selected. In schoolchildren aged 7 to 11 years, a spot urine sample was collected for measurement of urinary iodine, dried blood spots were collected for measurement of thyroglobulin, and goitre was assessed by palpation. Iodine content of salt samples and local selling points was determined by coloration using rapid test kits and titration method.

RESULTS

Of 623 schoolchildren enrolled, complete data was obtained from 589. The overall median urinary iodine concentration (UIC) was 51.2 μg/L indicating mild-to-moderate iodine deficiency. Among all children, 46.6% (95% Confidence Interval (CI) = 42.4%-50.6%) of children were found to be goitrous (grade 1 goitre: 30.6%, 95% CI = 26.9%-34.5%; grade 2 goitre: 16.0%, 95% CI = 13.1%-19.2%). The risk factor for goitre remaining significant in the multivariable logistic regression model was 'buying salt once a month' (OR = 2.89, 95% CI = 1.01-8.22) and 'buying salt once every six months' (OR = 2.26, 95% CI = 1.01-5.04) compared to 'buying salt every one or two weeks'. The overall median thyroglobulin concentration was elevated at 13.9 μg/L. Of the salt samples from households and selling points, one third were adequately iodised, one third insufficiently and one third were not iodised.

CONCLUSION

Iodine deficiency remains a serious health issue among children in southern Tajikistan. There is a persisting high prevalence of goitre, elevated thyroglobulin and low UIC despite interventions implemented by Tajikistan and international partners. Quality control of salt iodine content needs to be improved. Continued efforts to raise awareness of the health effects of iodine deficiency are needed to increase consumer demand for iodised salt.

Iodine intake as a determinant of thyroid disorders in populations

Depending on the availability of iodine, the thyroid gland is able to enhance or limit the use of iodine for thyroid hormone production. When compensation fails, as in severely iodine-deficient populations, hypothyroidism and developmental brain damage will be the dominating disorders. This is, out of all comparison, the most serious association between disease and the level of iodine intake in a population. In less severe iodine deficiency, the normal thyroid gland is able to adapt and keep thyroid hormone production within the normal range. However, the prolonged thyroid hyperactivity associated with such adaptation leads to thyroid growth, and during follicular cell proliferation there is a tendency to mutations leading to multifocal autonomous growth and function. In populations with mild and moderate iodine deficiency, such multifocal autonomous thyroid function is a common cause of hyperthyroidism in elderly people, and the prevalence of thyroid enlargement and nodularity is high. The average serum TSH tends to decrease with age in such populations caused by the high frequency of autonomous thyroid hormone production. On the other hand, epidemiological studies have shown that hypothyroidism is more prevalent in populations with a high iodine intake. Probably, this is also a complication to thyroid adaptation to iodine intake. Many thyroid processes are inhibited when iodine intake becomes high, and the frequency of apoptosis of follicular cells becomes higher. Abnormal inhibition of thyroid function by high levels of iodine is especially common in people affected by thyroid autoimmunity (Hashimoto's thyroiditis). In populations with high iodine intake, the average serum thyroid-stimulating hormone (TSH) tends to increase with age. This phenomenon is especially pronounced in Caucasian populations with a genetically determined high tendency to thyroid autoimmunity. A small tendency to higher serum TSH may be observed already when iodine intake is brought from mildly deficient to adequate, but there is at present no evidence that slightly elevated serum TSH in elderly people leads to an increase in morbidity and mortality.

CONCLUSION

Even minor differences in iodine intake between populations are associated with differences in the occurrence of thyroid disorders. Both iodine intake levels below and above the recommended interval are associated with an increase in the risk of disease in the population. Optimally, iodine intake of a population should be kept within a relatively narrow interval where iodine deficiency disorders are prevented, but not higher. Monitoring and adjusting of iodine intake in a population is an important part of preventive medicine.

Goiter and other iodine deficiency disorders: A systematic review of epidemiological studies to deconstruct the complex web

A systematic review of the available literature on goiter and other iodine deficiency disorders (IDDs) was carried out with the aim of analyzing available evidence and providing inputs to the policy makers and program formulators regarding the entire issue. The findings point to major issues such as the following: methodological issues in epidemiology of goiter and other iodine deficiency disorders (IDDs); lacunae in causal linkages; inadequate attention to multicausality; flawed assessment of the impact of intervention, i.e., iodized salt; and harmful effects of iodine not given due cognizance. Most of the research to date has been unidirectional and does not provide comprehensive data on all aspects of IDDs. To further compound the issue, many independent researchers, on finding something different from the existing dominant paradigm (iodized salt as panacea for goiter) have tended to ignore these in their final conclusions and recommendations. Thus, evidence from this systematic review demonstrates enough basis to start a debate on the entire issue, recognizing opposing research findings while continuing with the present strategy. This imposes specific problems and necessitates area-specific solutions instead of a universal solution, which apart from being less effective may be harmful in the long run.

Interaction of two public health problems in Turkish schoolchildren: nutritional deficiencies and goitre

Objective

The aim of the present study was to determine the interaction of and association between frequency of goitre detected by palpation, nutritional status evaluated by anthropometric indices and socio-economic status in school-aged children.

Subjects

One thousand and eighteen prepubertal and pubertal children (aged 6–14 years) attending primary schools in an urban area were included in this study.

Design and setting

All subjects were evaluated for the presence of goitre and nutritional status. Thyroid size was assessed using the World Health Organization's (WHO) palpation system (1960). Severity of protein–energy malnutrition (PEM) was based on WHO criteria. Children were grouped into four categories of socio-economic status.

Results

Eight per cent of children were detected to have goitre by palpation. Body mass index and weight-for-height were significantly lower in children who had palpable goitre than in children who did not have goitre (P < 0.05). Frequencies of having palpable goitre and being stunted and underweight were especially higher in children with very low socio-economic status (P = 0.016, 0.01 and 0.01, respectively). Frequency of being stunted, underweight and wasted in children with palpable goitre did not change significantly according to socio-economic status (P>0.05). In logistic regression analyses, the most important factor in detection of palpable goitre was socio-economic status (B = 0.517, P = 0.004). Fathers' education and occupation were found to be most significant (P = 0.031 and 0.020, respectively).

Conclusion

Children detected to have palpable goitre were thinner. However, nutritional disorders were not more frequent among children with palpable goitre compared with children without goitre. Goitre and nutritional deficiencies were more common in children with lower socio-economic status but the frequency of nutritional disorders in children with palpable goitre did not change according to socio-economic status.