Prevalence of Thyroid Disorders in School Children in Delhi
Homeopathic Journal :: Volume: 5, Issue: 4, Feb 2012 (General Theme) - from Homeorizon.com
|Article Updated: Feb 29, 2012|
PREVALENCE OF THYROID DISORDERS
IN SCHOOL CHILDREN IN DELHI -
POST IODIZATION SCENARIO
An epidemiological survey conducted by
SHMC & Hospital and Institute of Nuclear Medicine & Allied Sciences, Delhi, India,
under the first phase of EMR project on
"Effects of Homoeopathic treatment on natural history of autoimmune thyroiditis"
Screening of 4543 children between 6-18 years of age from different schools of Delhi was done during the first phase of research study under EMR project by AYUSH, for thyroid function status-clinically, serologically & ultrasonographically. Data of 4506 children has been analyzed & it has been found that goiter is prevalent at mild endemic level in children (17%) even after two decades of iodization. Significant increase in anti TPO ab positivity (6.39%) and thyroid dysfunction (11.92%) raises suspicion about the role of environmental goitrogens and prolonged iodine supplementation.
anti thyro-peroxidase antibody (anti TPO ab), free T3 (FT3), free T4 (FT4), goiter, Iodine deficiency disorders (IDDs), subclinical hypothyroidism, thyroid autoimmunity, universal salt iodization (USI).
Iodine is an important micro-nutrient required for human nutrition. Iodine deficiency disorders (IDDs) are one of the major world wide public health problems of today which cause wide spectrum of disabilities. It includes impairment of reproductive functions, lowering of IQ levels in school age children, goiter, deaf mutism, mental defects, weakness and paralysis of muscles as well as lesser degree of physical dysfunction1. Many studies conducted all over India had shown high prevalence of goiter2-5. A nation wide goiter survey revealed that out of 283 studied districts of 29 states and 04 Union territories, 235 have prevalence of endemic goiter6. In an attempt to eliminate iodine deficiency and to comply with the International goal of Universal salt iodization (USI), compulsory iodization of all table salts was introduced in India in 1983. In June 1992 the National Goiter Control Programme was appropriately redesigned as "National Iodine Deficiency Disorders Control Programme (NIDDCP)", in recognition of the spectrum of disorders due to iodine deficiency.
Optimal thyroid function is essential for normal growth and development in young population. Autoimmune thyroiditis is becoming increasingly prevalent in children as evident from goiter surveys7-8. Subjects with autoimmune thyroiditis manifest clinically as euthyroidism, sub clinical hypothyroidism, overt hypothyroidism. Presence of anti TPO ab predicts progressive thyroid failure consequently affecting growth of children.
It was proposed to study the immunomodulatory effect of homoeopathic system of medicine in autoimmune thyroiditis, well in line with the priority area regarding research on the preventive and promotive aspects of AYUSH practices and therapies. During the first phase of this study an epidemiological survey has been conducted in various schools of Delhi to assess the rate of prevalence of goiter, thyroid functional status, and presence of thyroid autoimmunity among school children in Delhi.
To evaluate the prevalence of goiter, thyroid functional status, and presence of thyroid autoimmunity among school children in Delhi.
Material & Methods
Selection of study areas: Seven schools were randomly selected covering different regions of Delhi.
Selection of population: The school children in age group of 6 - 18 years from both the sexes were selected.
Screening Module: The screening was conducted in 4543 school children. 4506 children were evaluated clinically for enlargement of thyroid (goiter) by palpation method endorsed by WHO/UNICEF/ICCIDD9.
Children were screened for thyroid disorders by thyroid function tests (FT3, FT4 and TSH), serological markers for thyroid autoimmunity (anti TPO ab) and echogenicity & nodularity of thyroid by ultrasonography.
All the investigations were done in children whose parents gave consent for them. Data was collected in pre formed formats. All investigations were performed at Institute of Nuclear Medicine & Allied Sciences (INMAS) Timarpur, Delhi.
FT3, FT4 - RIA (Immunotech, Beckmen Coulter, Pragni, Czech Republic)
- FT4 normal range: 11.5 - 23pM/L
- FT3 normal range: 2.5 - 5.8 pM/
TSH - Immunoradiometric assay (IRMA, Immunotech)
- Normal range 0.17 - 5.2µIU/ml
- Range of measurement: 0.025-150 µIU/ml
- Intra assay Coefficient of Variation: <3.7%
- Inter assay Coefficient of Variation: <8.6%
Anti TPO Antibodies: Electro Chemiluminescence assay (ECL, Cobas-Roche Elecsys 1010 analyzer)
- Range of measurement is 5-600 IU/ml
- TPO values ≥34 IU/ml are considered + ve
- Intra assay Coefficient of Variation was < 4.2%
- Inter assay Coefficient of Variation < 9.2%
Ultrasound - Portable US using 7.5 MHz linear transducer to assess echogenicity and nodularity.
Total of 4506 children in the age group of 6 - 18 years are included in the study (34.73% boys, 65.27% girls).
- Total goiter prevalence: 768/4506 = 17%
- Boys: 9.7%
- Girls: 20.9%
- Goiter grade I: 15.9%
- Goiter grade II: 1.10 %
- Clinically palpable nodules: 0.11%
- Incidentalomas on ultrasonography: 0.02%
Table 1: Goiter Prevalence in different Age groups
|Age Group||Goiter Prevalence|
Prevalence of anti TPO antibodies:
Serological test for anti TPO ab is done in 2844 children (goitrous and non goitrous).
- Total prevalence of anti TPO antibodies: 182/2844= 6.39%
- Male: 4.08%
- Female: 7.20 %
Table 2: Prevalence of anti TPO ab in goitrous and non goitrous subjects
|Prevalence in boys||Prevalence in girls||Total prevalence|
|Goitrous subjects||10.31 %||13.5 %||12.93 %|
|Non goitrous subjects||2.63 %||4.64 %||4.08 %|
Table 3: Prevalence of Anti TPO anti bodies in children of different age groups
|Age Group||All subjects||Sex|
|11 - 15 yrs||6.25%||4.36%||6.94%|
Prevalence of thyroid dysfunction in school children in Delhi
Total of 4284 children have been screened for thyroid dysfunction and 511(11.92 %) have been found to be having different thyroid disorders which have been depicted in table 4.
Table 4: Prevalence of Thyroid dysfunction in children
Total No of FT3, FT4, TSH
tests done (n- 4284)
|Non goitrous subjects||3545||33(0.93%)||336(9.47%)||05(0.14%)||06(0.16%)|
|Non Goitrous girls||2234||22(0.98%)||210(9.4%)||05(0.22%)||05(0.22%)|
|Non goitrous boys||1311||11(0.83%)||126(9.6%)||0||01(0.07%)|
Prevalence of thyroid dysfunction in goitrous subjects (refer to table no. 4)
- Total goitrous subjects: 739
- Boys with thyroid dysfunction amongst goitrous subjects: 21/146 = 14.38 %
- Girls with thyroid dysfunction amongst goitrous subjects: 110/593 = 18.54 %
- Total prevalence of thyroid dysfunction amongst goitrous subjects 131/739 = 17.72 %
Prevalence of thyroid dysfunction in non goitrous subjects (refer to table no. 4)
- Total non goitrous subjects: 3545
- Boys with thyroid dysfunction amongst non goitrous subjects: 138/1311= 10.52 %
- Girls with thyroid dysfunction amongst non goitrous subjects: 244/2234 = 10.92 %
- Total prevalence of thyroid dysfunction amongst non goitrous subjects: 380/3545= 10.71%
The most widely accepted marker to evaluate the severity of IDD in a region is the prevalence of endemic goiter in school going children. On the basis of its prevalence, WHO/UNICEF/ICCIDD recommended the criteria to understand the severity of IDD as a public health problem in a region. According to these criteria, a prevalence rate of 5.0 - 19.9 % is considered as mild; 20.0 - 29.9 % as moderate and prevalence rate of above 30 % is considered as a severe public health problem.
Delhi, was not included in the classical Himalayan endemic goitre belt described by Ramalingaswami10-11 in his various studies done in 1953 & 1973. In 1979 a survey for goiter prevalence in Delhi was conducted by Pandav et al12 with 3200 school children for goitre prevalence in the two areas of Union Territory of Delhi namely Kalkaji and Chandani Chowk. The observed prevalence of goitre in 2214 school children of Kalkaji was 54 per cent while it was 55 per cent in Chandani Chowk school children. Goitre prevalence was significantly greater in girls, so also the severity of goitre among them.
A study conducted by Chaturvedi S. et al, Department of Preventive and Social Medicine, UCMS, Delhi on a sample size of 1075 children from schools or rural south Delhi have shown goiter prevalence of 16 % after the successful implementation of USI in Delhi.
In a country wide study conducted by Marwaha et al (2003) on a sample size of 14762 school children in age group of 6 - 18 years, from different states and union territories of India. Children were evaluated for goiter prevalence, urine iodine & thiocyanate excretion, functional status of thyroid as well as serological & cytopathological markers for thyroid autoimmunity. The overall goiter prevalence was 23 % (27.1 % girls and 17.8 % boys with P<0.001). Subjects belonging to poor socio- economic strata had higher goiter prevalence. High titres of thyroid antibodies were present more in goitrous subjects than in non goitrous and more in girls (7.3 %) than boys (2.35 %). Autoimmunity was positive more in goitrous subjects with thyroid dysfunction than in euthyroid subjects. The study suggested that anti thyroidal environmental goitrogens may have a possible role for persistence of goiter. Prolonged iodine exposure may have some role in significant increase in thyroid dysfunction.
In this present study conducted during the first phase of the research project on 4506 school children between the age group of 6 - 18 years, total goiter prevalence is found to be 17 % (grade I - 15.9 %, grade II - 1.10 %). Girls have 20.9 % of goiter prevalence rate in comparison to boys, having prevalence rate of 9.7 %. The prevalence of goiter increases with age, lowest in the age group of 6 - 11 years and maximum in the age group 11 - 15 years (pubertal age group).
Goitrous children have three times more prevalence of TPO ab than non goitrous group. The prevalence rate of auto immunity in goitrous boys is 10.31 % and goitrous girls is 13.5 % with overall prevalence of 12.93 % in goitrous subjects. In non goitrous subjects, the prevalence rate of auto immunity in girls is 4.64 % and boys is 2.63 % with overall prevalence rate of 4.08 %.
Total prevalence of thyroid dysfunction found to be 11.92 % (17.72 % amongst the goitrous and 10.71 % in non goitrous subjects). Most common thyroid dysfunction is subclinical hypothyroidism in both the sexes.
Goiter prevalence of 17 % and increased thyroid auto immunity even after iodization Programme in Delhi indicates that iodine deficiency is not the sole reason for it. High prevalence of auto immunity points towards some environmental goitrogens which may be responsible for it. Indian cyanogenic plant foods which contains large amounts of thiocyanate precursors namely cyanogenic glucosides, thioglucosides and thiocyanates, used as common vegetables may have potent anti thyroid activity and cyano genic effect which may be responsible for increased prevalence of auto immunity and goiter13.
A single blind case control 18 months follow-up study was undertaken to evaluate the effectiveness of Homoeopathic treatment in cases of Sub clinical hypothyroidism and to study the progression of Sub clinical hypothyroidism to overt hypothyroidism at OPD ofNHMC & Hospital and Institute of Nuclear Medicine & Allied Sciences, Delhi, India14. Decrease in TSH levels in 77.5% patients on homoeopathic treatment clearly indicated that Homoeopathic Medicines due to their infinitesimal light isotopic forms are capable of penetrating the Hypothalamus-Pituitary Axis. Out of 8 patients proved to have autoimmune thyroiditis either by FNAC or by presence of TPO antibodies, 5 cases became anti TPO negative on homoeopathic treatment.
None of the patients on homoeopathic treatment with sub clinical hypothyroidism had gone into overt hypothyroidism. The above observations suggest the potential role of homeopathy in reversing the functional & immune disturbances of thyroid gland.
Role of homoeopathy in modulating the auto immunity and thyroid dysfunction in children on larger sample size is yet to be explored during second phase of the study.
- It has been observed that after more than two decades of universal salt iodization there is remarkable decline in the goiter prevalence but mild endemicity still persists.
- There may be some other reasons responsible for goiter prevalence other than low iodine intake e.g. environmental goitrogens, which may be responsible for it should be further investigated. Significant increase in overall anti TPO ab positivity and thyroid dysfunction raises suspicion about the role of prolonged iodine supplementation.
- The most common form of thyroid dysfunction in school going children in Delhi is subclinical hypothyroidism.
- The above observations suggest the there is a need to screen and study large sample sizes to better understand the relation of iodine and thyroid antibodies.
- Vir., S., 1994. Universal iodization of salt: A mid decade goal. In: Sachdev HPS and Choudhary (Eds.) Nutrition in Children - Developing country concerns. New Delhi: Cambridge Press, pp: 525-535.
- Directorate General of Health Services (DGHS). Ministry of Health and Family Welfare, Govt. of India. Policy Guidelines on National Iodine Deficiency Disorders Control Programme. New Delhi: DGHS, Ministry of Health and Family Welfare, Govt. of India; 2003. p. 1-10.
- Epidemiological survey of endemic goiter and endemic cretinism. New Delhi: Indian Council of Medical Research; 1989.
- Report of a Joint WHO/UNICEF/ICCIDD Consultation on Indicators for Assessing Iodine Deficiency Disorders and their Control Programmes. Geneva: World Health Organization; 1992. p. 22 - 9.
- Control of iodine deficiency through safe use of iodized salt. ICMR bull 1996; 26: 41-6.
- National iodine deficiency disorders control Programme: National Health Programme Series 5. Published by Deptt. of Communication, National Institute of Health and Family Welfare, New Delhi, 2003: p. 99.
- Gopalakrishnan Sripathy, Singh S.P, Walia Ram Prasad,Sushil Kr.Jain,Vinod kumar Amberdar,Sankar Rajan;Prevalance of goiter and autoimmune thyroiditis in school children in Delhi,India after two decades of salt iodisation:Journal of Pediatric Endocrinology and Metabolism,2006,vol19 pp889-893
- Marwaha R. K., Tandon N., Gupta N, Karak A.K., Verma K, Kochupillai N. Residual goiter in post iodization phase: Iodine status, thiocyanate exposure and auto immunity. Clin Endocrinol 2003; 59 (6): 672 - 681.
- WHO/UNICEF/ICCIDD. Indicators for Assessing Iodine Deficiency Disorders and their Control through Salt Iodization. WHO/NUT/94.6, 1994.
- Ramalingaswami V., The problem of goiter prevention in India, Bull. World Hlth. Org. 1953, 9, 275-281
- Ramalingaswami V., Prevention of endemic goiter with iodized salt, Bull. World Hlth. Org. 1973, 49, 307-312.
- Pandav, et al. Endemic goiter in Delhi. December 1979
- Amar K. Chandra et al, Iodine nutritional status of children in North east India, Indian Journal of Pediatrics, Volume 73 - September, 2006.
- Archana Narang, V. K. Khanna, R. K. Marwaha, Evidence to evaluate the efficacy of Homoeopathic treatment in Subclinical Hypothyroidism, Asian Journal of Homoeopathy 2007,vol1No.1(1):10-13
- 1 Principal, Dr. B. R. Sur Homoeopathic Medical College & Hospital (SHMC), New Delhi, India,
- 1* Medical officer (T), SHMC, shmc.thyroidclinic[at]gmail[dot]com
- 2 Deputy Director, Directorate of ISM & H, Delhi, India
- 3 Sr. Research Fellow, SHMC, New Delhi.
- 4 Joint Director, Institute of Nuclear Medicine & Allied Sciences, Timarpur, Delhi