Dietary supplies of iodine and thiocyanate in the etiology of endemic goiter in Tripura

Prevalence of goitre and iodine deficiency among school children (6-12 years) in rural areas of North Karnataka, India: A cross-sectional survey, 2016-19

Introduction

Iodine deficiency disorders (IDD) have remained an unresolved public health problem in India. In this survey, we have estimated the prevalence of IDD among 6-12 years of school children in rural areas of north Karnataka, India and estimated the prevalence of low iodine content (<15 ppm) in salt at the household level and urine iodine excretion in this population.

Material and Methods

In this cross-sectional survey, we recruited 16,827 children between 6 and 12 years of age through multistage sampling from six districts. Goitre was examined clinically for all children. Household-level salt iodine estimation and urinary iodine estimation were carried out among a subset of the participants.

Results

Overall prevalence of goitre was 17.1% (95% CI: 16.5, 17.7). Out of this, 76.7% (n = 2116) had Grade-1 goitre, and 23.7% (n = 656) had Grade-2 goitre. The prevalence of goitre was higher among females (17.9%, vs. male 16.4%, P < 0.05). The prevalence of low iodine content (<15 ppm) in salt was 48.5% (95%CI: 46.7, 50.3). The overall median iodine excretion in urine was 85 μg/L (IQR: 60-150 μg/L). In total, 37.2% (n = 601) had mild iodine deficiency, 5.2% (n = 84) had moderate deficiency, and 10.1% (n = 163) had severe deficiency. All parameters showed high inter- and intradistrict variations.

Conclusion

North Karnataka has a high goitre prevalence. Low use of iodized salt can be a major reason for the high prevalence of the condition. Ensuring the availability of iodized salt in this region and periodic surveillance to measure the impact of the programme should be the priority in this region.

Goitre and urinary iodine excretion survey in schoolchildren of Kashmir Valley

BACKGROUND

An extensive survey on schoolchildren in Kashmir Valley in 1995 showed a high prevalence of goitre, making it imperative to have a relook at our iodine status, 15 years postiodization.

OBJECTIVE

To study the total prevalence of goitre and urinary iodine excretion (UIE) in Kashmiri schoolchildren, 15 years postiodization.

DESIGN

A cross-sectional survey, covering 9576 schoolchildren, aged 5-15 years (5988 in 6-12 year age group) was conducted. Goitres were graded as per WHO/UNICEF/ICCIDD. UIE was measured by the arsenic acid reduction in ceric ions method and was estimated in 208 subsampled children. Results were compared with that of 1995 survey.

RESULTS

The overall prevalence of goitre in the present study was 3·8% (95% CI: 3·4-4·2) and 3·7% (95% CI: 3·2-4·2) in those aged 6-12 years. No significant difference in prevalence of goitre was observed between boys and girls overall (3·6% vs 4·1%. P > 0·2), nor in the 6-12 year age group (3·3% vs 4·0%, P > 0·1). There was a significant trend of increasing prevalence of goitre with age (P < 0·005). UIE ranged from 12 to 397 μg/g.creatinine (median, 104); 11% subjects had UIE of <50 μg/g.creatinine. Overall, prevalence of goitre was significantly lower (3·8% vs 45·2%, P < 0·001), and mean UIE was significantly higher (123·6 ± 5·3 vs 49·60 ± 3·55 μg/g.creatinine, P < 0·001), compared to that in the 1995 survey.

CONCLUSION

The marked improvement in overall iodine nutrition in Kashmir Valley- one and a half decades after implementation of salt iodization should encourage healthcare providers to make tangible efforts for implementation of iodization programmes in areas with iodine deficiency.

Role of bamboo-shoot in the pathogenesis of endemic goiter in manipur, north East India

OBJECTIVE

Endemic goiter is prevalent in the iodine-sufficient region of Manipur, India. Bamboo shoot (BS), a goitrogenic plant food, are consumed regularly in the area. The objective of this study was to examine the role of BS in the pathogenesis of endemic goiter.

METHODS

Goiter prevalence, urinary iodine, and thiocyanate (SCN) excretion in school children, iodine content in drinking water, and the household consumption of salt fortified with iodine were measured. To confirm the goitrogenic potential of BS, its progoitrogenic constituents were fed to rats as part of an iodine-sufficient diet, after which the animals' thyroid gland morphology and functional status were assessed.

RESULTS

Goiter prevalence was 31% in 4852 children, and the median urinary I and SCN levels were 176.3 μg/L and 0.962 ± 0.190 mg/dL, respectively. Of the households assessed, 90% consumed salt fortified with adequate iodine. Progoitrogenic constituents were high in BS from Manipur. Increased thyroid weight, hypertrophy and hyperplasia of follicular cells, decreased thyroid peroxidase activity, and low serum thyroxine (T4) and triiodothyronine (T3) levels were observed in BS-fed rats.

CONCLUSION

Nearly one third of the studied participants had palpable goiter, despite a successful salt iodine fortification program. SCN from BS causes goiter in iodine-sufficient experimental animals. Similar ingestion in study participants was confirmed and is the likely cause for the persistence of endemic goiter in the Manipur region.

Thyromegaly and iodine nutritional status in a tertiary care hospital in South India

AIM AND OBJECTIVES

1. To assess the iodine nutritional status in patients with goiter by measuring urinary iodine excretion. 2. To compare the iodine nutritional status with the thyroid function and correlate with the type of thyroid disease.

STUDY DESIGN

Case control study.

MATERIALS AND METHODS

Three hundred patients with goiter and one hundred euthyroid healthy non-goitrous volunteers were included in this study.

RESULTS AND CONCLUSIONS

All patients had elevated urinary iodine suggesting excess iodine intake and absence of iodine deficiency. Complications known to be associated with excess iodine, viz., benign goiter (35%), iodine-induced hyperthyroidism or thyrotoxicosis (34%), thyroiditis (16%) and cancer of thyroid (15%) have been observed in this study. Therefore, continued supplementation of edible salt fortified with iodine should be monitored carefully, and supplementation programs should be tailored to the particular region.

Iodine nutritional status of children in North East India

OBJECTIVE

To assess the iodine nutritional status of school children in selected areas of Imphal West District of Manipur where endemic goitre and associated iodine deficiency disorders (IDD) are prevalent in the post-salt iodization period.

METHODS

A total of 961 school children in the age group 6-12 yrs of both sexes were clinically examined for goiter from three study areas- one from rural block and two from urban areas. One hundred twenty urine samples were analysed for iodine and thiocyanate respectively. One hundred and five edible salt samples were also collected from the households to evaluate the iodine content. Drinking water samples from different sources were collected and iodine level was analysed to study the bioavailability of iodine in the region.

RESULTS

The total goiter rate was 34.96% (Grade 1- 32.15%; Grade 2- 2.81%) showing that IDD is a severe public health problem. The median urinary iodine levels in the studied areas were in the ranges from 12.5-17.5 microg/dl indicating no biochemical iodine deficiency in the region. Mean urinary thiocyanate level was 0.839+/-0.33 mg/dl showing that the people consume sufficient foods containing thiocyanate precursors. About 82% salt samples had iodine level more than 30 ppm and the iodine content in salt samples less than 15 ppm was only about 3% indicating the salt samples at house hold contain adequate iodine.

CONCLUSION

Iodine content in drinking water samples ranged from 1.8-2.6 microg/l showing that the studied region is environmentally iodine deficient. Inspite of the consumption of adequate iodine, the existing goiter prevalence among school children during post salt iodization phase ensures that environmental factors other than iodine deficiency may have the possible role in the persistence of endemic goiter in the population. The role of thiocyanate in this regard may not be ruled out.