Thyroid status two decades after salt iodization: country-wide data in school children from India

Acquired Hypothyroidism in Children

Acquired hypothyroidism is generally also referred to as juvenile hypothyroidism. Hypothyroidism is due to the deficient secretion of thyroid hormones causing metabolic and neurological sequelae at the cellular level. It can present as overt hypothyroidism wherein the thyroid hormones (T4 and T3) secretion fall and thyrotropin (TSH) rises. Acquired hypothyroidism frequently presents between 9 and 11 y of age and is rarely seen before 4 y of age. Approximately 80% of the children and adolescents are asymptomatic at the time of diagnosis. Children with moderate to severe hypothyroidism often present for evaluation of poor growth, constipation, lethargy and/or dry skin. A detailed history and examination will provide us with enough clues for diagnosing hypothyroidism. Primary hypothyroidism can be diagnosed with raised TSH with subnormal levels of T3 and T4. Titres of thyroid antibodies - Anti-thyroperoxidase (TPO) and anti-thyroglobulin (ATG) antibodies, will be high in autoimmune hypothyroidism. Subclinical hypothyroidism is diagnosed with mildly elevated or high normal levels of TSH with free T4 being in the normal range. Insufficient secretion of thyrotropin from the pituitary causes central hypothyroidism. Acquired hypothyroidism is treated by replacement with levothyroxine. Regular monitoring of thyroid profile is necessary for adjusting doses of levothyroxine. Close monitoring and individualization of levothyroxine therapy is essential for normal growth and development of the child.

Thyroid Function, Urinary Iodine, and Thyroid Antibody Status Among the Tribal Population of Kashmir Valley: Data From Endemic Zone of a Sub-Himalayan Region

Background: There are scarce data on the prevalence of thyroid disorders and urinary iodine status among tribal populations of India, with no reported data from Kashmir valley.

Objectives: To estimate the prevalence of thyroid disorders and evaluate urinary iodine concentration (UIC) and thyroid autoantibody status among Gujjar and Bakerwal tribes of Kashmir valley.

Methods: This cross-sectional study recruited tribal subjects using multistage cluster sampling from 5 out of 22 districts of Jammu and Kashmir (J&K). Using a predesigned questionnaire, the details of past or current medical history and drug intake, including thyroid hormone medication etc. were recorded after obtaining an informed consent. Examination included anthropometry (height, weight, waist circumference), blood pressure measurement, and relevant general physical examination focusing on goiter palpation, while as laboratory assessment included estimation of serum thyroid hormone levels, antithyroid peroxidase antibody (anti-TPO Ab), and urinary iodine concentration.

Results: A total of 763 subjects (56.4% women and 43.6% men) with a mean(±SD) age of 39.46 (±17.51) ranging from 10 to 85 years and mean(±SD) body mass index (BMI) of 21.28 (±4.16) kg/m² were studied. Goiter was detected in 6.8%, while 33.2% subjects had some form of thyroid dysfunction (including 24.1% subclinical and 6.8% overt hypothyroidism). Subclinical and overt hyperthyroidism were observed in 1.3 and 0.9% of cases, respectively. Anti-TPO Ab was elevated in 13.6%, while the median [interquartile range (IQR)] for UIC was 154.50 (135) μg/L [156.13 (134) μg/L in men and 147.26 (136) μg/L in women]. A negative correlation was observed between UIC and anti-TPO Ab (r = −0.087, P = <0.05).

Conclusion: These novel data on iodine and thyroid status among a tribal population of India generally inhabiting in remote sub-Himalayan belts demonstrate high prevalence of subclinical hypothyroidism (SCH) with persistent iodine deficiency. These preliminary data may warrant large well-designed studies to carry out comprehensive assessment of the problem in this high-risk and marginalized population.

Goiter Prevalence and Thyroid Autoimmunity in School Children of Delhi

INTRODUCTION

Several studies from India, performed prior to 2010, have reported a goiter prevalence of greater than five per cent in school going children. There has been considerable success in universal salt iodization efforts in the past decade. We studied the prevalence of goiter and thyroid autoimmunity in school going children in Delhi between 2010 and 2014 to assess the impact of salt iodization.

MATERIALS AND METHODS

The study employed the population proportionate to size (PPS) cluster sampling methodology to select subjects between the age of six and 14 years, from all 34 wards of 9 districts of Delhi. Cluster randomization sampling design was followed and in this way we identified 30 wards, from each of which 90 children were recruited for the study. The total sample size was 2700 children. Estimation of fT3, fT4, TSH, anti-TPO antibodies and urine iodine concentration (UIC) was done for 10% of the study population.

RESULTS

The prevalence of goiter in this study in the 6-14 years age group was 6.4%. The prevalence of goiter was higher in females (7.7% compared to 5.3% in males, P = 0.01). In the 270 subjects who were selected for biochemical evaluation, subclinical hypothyroidism was seen in 18.4% and positive anti-TPO antibodies were seen in 14.8%. The median UIC was 150 μg/L.

CONCLUSIONS

There is improvement in goiter prevalence in the post-iodization period in Delhi. But still, residual goiter rates are above five per cent suggesting presence of other causes of goiter in this area. There is a high prevalence of thyroid autoimmunity in this population.

The effect of 17 years of increased salt iodization on the prevalence and nature of goiter in Croatian schoolchildren

Background High goiter prevalence caused by iodine deficiency (medium content 5.6 mg potassium iodide [KI]/kg of salt, median urine iodine concentration [UIC] 68 μg/L) in Croatia was observed in 1991 and 1995 when salt was iodized with 10 mg KI/kg. A new regulation introduced in 1996, specified 25 mg KI/kg of salt resulting in an increase of median UIC to 248 μg/L. Afterwards, goiter prevalence was only assessed in two small studies. Methods In this study, we investigated the prevalence and etiology of goiter in 3594 schoolchildren 17 years after an increase in salt iodization in Croatia. Thyroid size was determined by palpation in 1777 girls and 1817 boys aged 10-18 years. In goitrous children, a thyroid ultrasound and thyroid-stimulating hormone, free thyroxine (fT4), free triiodothyronine (fT3), thyroid peroxidase (TPO) and thyroglobulin (TG) antibody measurements were performed. Results Goiter was found in 32 children (0.89% vs. 2.8% in 1991, p<0.00001 and 27% in 1995, p<0.00001), simple goiter (SG) in 18/32 (56%) goitrous children vs. 126/152 (82.8%) in 1991 p<0.00001, autoimmune thyroiditis (AT) in 13/32 (40.6%) vs. 19/152 (12.5%) in 1991 p<0.0009, nodules in four: two cysts, toxic adenoma and carcinoma (in 1991 two adenomas and one cyst), Graves' disease was not found (four in 1991). Subclinical hypothyroidism was found in three children. Thyroid disease was diagnosed in four of 32 children before the investigation. Increased iodine supply decreased goiter prevalence and SG/AT ratio in goitrous patients. Conclusions As thyroid abnormalities were found in 0.89% of children and some required treatment, thyroid examination is important in apparently healthy children regardless of sufficient iodization.

Assessment of insulin like growth factor-1 and IGF binding protein-3 in healthy Indian girls from Delhi and their correlation with age, pubertal status, obesity and thyroid hormonal status

BACKGROUND

Population specific data and influence of sub-clinical hypothyroidism on insulin like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3) in Indian children is lacking. This study was undertaken to evaluate serum IGF-1 and IGFBP-3 and their correlation with age, gender, pubertal status and thyroid functions.

METHODS

A total of 840 apparently healthy school girls aged 6-18 years, were recruited for the study and underwent assessment of height, weight, body mass index, pubertal status and serum T3, T4, TSH, IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio.

RESULTS

The mean serum levels of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio were 381.8±240.5 ng/mL, 4.19±2.08 μg/mL and 40.5±37.2%, respectively. The serum IGF-1 and IGF-1/IGFBP-3 molar ratio increased significantly (p<0.0001) at 11 years followed by a steady yet non-significant rise till 16 years of age. A similar pattern was observed for IGFBP-3 showing a steep rise at 12 years and peaking at 16 years. Likewise, serum levels of IGF-1 and molar ratio of IGF-1/IGFBP-3 increased significantly with pubertal maturation from stage 1 to 3 and were higher in overweight girls compared to normal weight and obese girls. The growth factors were no different in girls with or without subclinical hypothyroidism.

CONCLUSIONS

There was no significant impact of age on IGF-1 and IGFBP-3 in pre-pubertal girls. A sudden marked increase at 11 years followed by a gradual rise in growth factors till 16 years is indicative of pubertal initiation and maturation. Subclinical hypothyroidism did not influence growth factors in girls.

Thyroid Function among Breastfed Children with Chronically Excessive Iodine Intakes

Iodine excess may impair thyroid function and trigger adverse health consequences for children. This study aims to describe iodine status among breastfed infants with high iodine exposure in the Saharawi refugee camps Algeria, and further assess thyroid function and iodine status among the children three years later. In 2010, a cross-sectional study among 111 breastfed children aged 0-6 months was performed (baseline study). In 2013, a second cross-sectional study (follow-up study) was conducted among 289 children; 213 newly selected and 76 children retrieved from baseline. Urinary iodine concentration (UIC) and breast milk iodine concentration (BMIC) were measured at baseline. UIC, thyroid hormones and serum thyroglobulin (Tg) were measured at follow-up. At baseline and follow-up, 88% and 72% had excessive iodine intakes (UIC ≥ 300 µg/L), respectively. At follow-up, 24% had a thyroid hormone disturbance and/or elevated serum Tg, including 9% with subclinical hypothyroidism (SCH), 4% with elevated fT3 and 14% with elevated Tg. Children with SCH had poorer linear growth and were more likely to be underweight than the children without SCH. Excessive iodine intakes and thyroid disturbances were common among children below four years of age in our study. Further, SCH seemed to be associated with poor growth and weight.

Subclinical hypothyroidism in children

NEED AND PURPOSE OF REVIEW

Subclinical hypothyroidism is a biochemical diagnosis characterized by raised thyroid stimulating hormone and normal free T4, without clinical features of hypothyroidism. This review analyzes the current evidence to arrive at a consensus and algorithm to manage this condition.

METHODS

We searched Pubmed, Cochrane and Embase for articles published between 1990 to 2014, and identified 13 relevant articles dealing with pediatric subclinical hypothyroidism which were suitable to include in our review.

CONCLUSIONS

Subclinical hypothyroidism is often a benign problem which requires expectant management with periodic monitoring of thyroid function tests and natural progression to overt hypothyroidism occur lot less frequently than expected. There is a paucity of robust randomized intervention studies, especially studies focusing on clinical outcomes. Thyroid replacement therapy is not justified in children with subclinical hypothyroidism when Thyroid stimulating hormone is <10 mIU/L. The main risk factors for progression to overt hypothyroidism are female sex, goiter, family history of thyroid disorder, strongly positive thyroid peroxidase antibodies and symptoms suggesting hypothyroidism. An algorithm for managing this condition is suggested.

Prevalence of thyroid dysfunction among young females in a South Indian population

BACKGROUND

Thyroid disorders are common in India but scarce data exists on its prevalence in young women.

MATERIALS AND METHODS

This study was conducted in female college students in seven colleges in Madurai District, Tamil Nadu. Thyroid-stimulating hormone (TSH) was used as the screening test to diagnose thyroid dysfunction. The abnormal TSH values were classified as mild TSH elevation (TSH 4.5-10 mIU/ml), significant TSH elevation (TSH > 10 mIU/ml), and low TSH (TSH < 0.4 mIU/ml).

RESULTS

A total of 1292 subjects were screened of whom 161 subjects (12.5%) had abnormal TSH. The overall prevalence of elevated TSH was 11% out of which 9.7% had mild TSH elevation. A low TSH was seen in 1.3% of the study population.

CONCLUSION

Thyroid dysfunction was common in young women in south India. One out of every eight young women had thyroid dysfunction, and mild TSH elevation was the most common abnormality.

Efficacy of homeopathic intervention in subclinical hypothyroidism with or without autoimmune thyroiditis in children: an exploratory randomized control study

INTRODUCTION

The decision to treat subclinical hypothyroidism (SCH) with or without autoimmune thyroiditis (AIT) in children, presents a clinical dilemma. This study was undertaken to evaluate the efficacy of individualized homeopathy in these cases.

METHODS

The study is an exploratory, randomized, placebo controlled, single blind trial. Out of 5059 school children (06-18 years) screened for thyroid disorders, 537 children had SCH/AIT and 194 consented to participate. Based on primary outcome measures (TSH and/or antiTPOab) three major groups were formed: Group A - SCH + AIT (n = 38; high TSH with antiTPOab+), Group B - AIT (n = 47; normal TSH with antiTPOab+) and Group C - SCH (n = 109; only high TSH) and were further randomized to two subgroups-verum and control. Individualized homeopathy or identical placebo was given to respective subgroup. 162 patients completed 18 months of study.

RESULTS

Baseline characteristics were similar in all the subgroups. The post treatment serum TSH (Group A and C) returned to normal limits in 85.94% of verum and 64.29% of controls (p < 0.006), while serum AntiTPOab titers (Group A and B) returned within normal limits in 70.27%of verum and 27.02%controls (p < 0.05). Eight children (10.5%) progressed to overt hypothyroidism (OH) from control group.

CONCLUSION

A statistically significant decline in serum TSH values and antiTPOab titers indicates that the homeopathic intervention has not only the potential to treat SCH with or without antiTPOab but may also prevent progression to OH.

Percutaneous ethanol ablation in managing predominantly cystic thyroid nodules: An eastern India perspective

AIMS

Percutaneous aspiration and ethanol injection (PEI) is effective in managing predominantly cystic (>50% cystic) thyroid nodules with efficacy ranging from 38-85%. We aimed to evaluate efficacy, safety, and factors determining outcomes of PEI in managing simple cystic (purely cystic) vs. complex cystic (having both cystic and solid components) thyroid nodules.

MATERIALS AND METHODS

Predominantly cystic thyroid nodules, without any ultrasonography and/or fine needle aspiration, evidence of malignancy were aspirated ultrasonography guided. Sterile 100% ethanol (50-100% volume aspirated) was injected and reviewed monthly for 3 months and thereafter 3 monthly. Responders were defined as ≥ 50% reduction in nodule volume.

RESULTS

Sixty-five patients out of 152 considered underwent PEI. Sixty patients [simple cystic (42) and complex cystic (18)] with mean follow-up of 12.3 ± 2.88 months were analyzed. Response rate of PEI was 78.33% [simple cystic (92.86%) and complex cystic (44.44%) nodules; P < 0.001]. Also, 31.67% patients achieved remission at 1(st) month. And, 46.67% patients achieved remission between 1-6-months follow-up. Kaplan Meier analysis showed significantly improved outcomes in patients with simple cystic nodules (P < 0.001). Cox-regression revealed type of nodule (simple cystic vs. complex cystic) to be predictive of outcome (P = 0.034). Complex cystic nodules were 67.6% less likely to go into remission, compared to simple cystic nodules. Baseline nodule size, aspirate, or volume of ethanol injected did not predict outcome.

CONCLUSIONS

PEI is safe and should be treatment of choice for simple cystic thyroid nodules. PEI for complex cystic thyroid nodules are associated with lower response, increased recurrence, and need for repeated PEI.

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.

Impact of body mass index on thyroid functions in Indian children

OBJECTIVE

There is controversy about the relation of thyroid functions and body mass index. The present study was aimed to assess the relationship between thyroid function and body mass index in Indian school children.

DESIGN

Population survey.

PATIENTS

Data were collected from 25 schools in 19 cities across five different geographical zones of India. Children, who consented, were evaluated for anthropometry and blood tests. Children were categorized as overweight and obese based on standard BMI criteria.

MEASUREMENTS

Serum samples were analysed for free T3, free T4, TSH and anti-TPO antibodies.

RESULTS

A total of 13,691 children in the age group of 5-18 years formed the study population. The mean age and mean BMI were 11·9 ± 3·0 years and 18·48 ± 3·89 kg/m² respectively. Among these, 2119 (15·5%) children were overweight and 536 (3·9%) were obese. Subclinical hypothyroidism was present in 943 (6·9%) children.FT3 and TSH levels increased and FT4 levels decreased with increasing BMI in euthyroid boys and girls. Prevalence of SCH was significantly higher in obese/overweight children (9·0%, vs 6·5%; P = 0·034) as compared with normal BMI children.

CONCLUSIONS

Serum FT3 and TSH were positively while FT4 was negatively associated with BMI in apparently healthy euthyroid children.

Prevalence of hypothyroidism in adults: An epidemiological study in eight cities of India

BACKGROUND

Hypothyroidism is believed to be a common health issue in India, as it is worldwide. However, there is a paucity of data on the prevalence of hypothyroidism in adult population of India.

MATERIALS AND METHODS

A cross-sectional, multi-centre, epidemiological study was conducted in eight major cities (Bangalore, Chennai, Delhi, Goa, Mumbai, Hyderabad, Ahmedabad and Kolkata) of India to study the prevalence of hypothyroidism among adult population. Thyroid abnormalities were diagnosed on the basis of laboratory results (serum FT3, FT4 and Thyroid Stimulating Hormone [TSH]). Patients with history of hypothyroidism and receiving levothyroxine therapy or those with serum free T4 <0.89 ng/dl and TSH >5.50 μU/ml, were categorized as hypothyroid. The prevalence of self reported and undetected hypothyroidism, and anti-thyroid peroxidase (anti-TPO) antibody positivity was assessed.

RESULTS

A total of 5376 adult male or non-pregnant female participants ≥18 years of age were enrolled, of which 5360 (mean age: 46 ± 14.68 years; 53.70% females) were evaluated. The overall prevalence of hypothyroidism was 10.95% (n = 587, 95% CI, 10.11-11.78) of which 7.48% (n = 401) patients self reported the condition, whereas 3.47% (n = 186) were previously undetected. Inland cities showed a higher prevalence of hypothyroidism as compared to coastal cities. A significantly higher (P < 0.05) proportion of females vs. males (15.86% vs 5.02%) and older vs. younger (13.11% vs 7.53%), adults were diagnosed with hypothyroidism. Additionally, 8.02% (n = 430) patients were diagnosed to have subclinical hypothyroidism (normal serum free T4 and TSH >5.50 μIU/ml). Anti - TPO antibodies suggesting autoimmunity were detected in 21.85% (n = 1171) patients.

CONCLUSION

The prevalence of hypothyroidism was high, affecting approximately one in 10 adults in the study population. Female gender and older age were found to have significant association with hypothyroidism. Subclinical hypothyroidism and anti-TPO antibody positivity were the other common observations.