Thyroid Research and Practice

ORIGINAL ARTICLE
Year
: 2012  |  Volume : 9  |  Issue : 1  |  Page : 9--11

Prevalence of thyroid autoantibodies in young asymptomatic females: A pilot study


Sabeena Shahulhameed, S. A. B. S. Anjali, Poulose K Poulose 
 Department of General Medicine, SUT Hospital, Pattom, Trivandrum, Kerala, India

Correspondence Address:
Poulose K Poulose
Department of General Medicine, SUT Hospital, Trivandrum, Kerala
India

Abstract

Studies have shown that autoimmune thyroiditis is diagnosed increasingly in recent times, probably due to facilities available for estimating the thyroid autoantibodies. This is a pilot study to estimate the prevalence of thyroid autoantibodies in young females, without any known thyroid disease or on thyroid medications. A total of 125 women in the age group 15 to 35 years were selected at random. Besides history taking and physical examination, estimation of TSH and antibodies against thyroid peroxidase and thyroglobulin were done in all the subjects. In 112 subjects (89.6%), thyroid autoantibody positivity was seen-in 52% both antibodies, in 33.6% antithyroid peroxidase alone, and in 4% antithyroglobulin alone were positive. A statistically significant association was found between thyroid autoantibodies and thyromegaly. All subjects with family history of thyroid disorders in their first degree relatives (18) had antibody positivity.



How to cite this article:
Shahulhameed S, Anjali S, Poulose PK. Prevalence of thyroid autoantibodies in young asymptomatic females: A pilot study.Thyroid Res Pract 2012;9:9-11


How to cite this URL:
Shahulhameed S, Anjali S, Poulose PK. Prevalence of thyroid autoantibodies in young asymptomatic females: A pilot study. Thyroid Res Pract [serial online] 2012 [cited 2019 Oct 23 ];9:9-11
Available from: http://www.thetrp.net/text.asp?2012/9/1/9/92389


Full Text

 Introduction



In India, thyroid disorders are the second commonest endocrine disease next to diabetes mellitus and its prevalence is much higher in females. Autoimmune thyroid disease is the most common organ-specific autoimmune disorder resulting in dysfunction of the thyroid gland. The common thyroid autoantibodies are antithyroid peroxidase (anti-TPO), antithyroglobulin (ATG), and thyroid-stimulating hormone (TSH) receptor antibodies (stimulating and blocking).

Interaction of genetic as well as environmental factors such as toxins, bacterial or viral infections lead to formation of autoantigens and accumulation of antigen presenting cells (APCs) in the thyroid. The APCs will present the autoantigens to the T helper (Th) lymphocytes in the draining lymph nodes of the thyroid gland. The interaction of Th lymphocytes with the presented autoantigens stimulates the cellular immune response and/or humoral response via B-cells resulting in apoptotic destruction of thyroid cells and production of antibodies, respectively. [1] The antibodies also damage the thyroid gland by combining with respective antigens, leading to hypothyroidism or transient hyperthyroidism due to rapid release of stored thyroid hormones.

In another study on pregnant patients published by us, thyroid autoantibodies were present in 29% cases. [2] These finding prompted us to find out the prevalence of thyroid autoantibodies in the general population. As thyroid disorders are more common in females and the presence of antibodies is associated with thyroid dysfunction, asymptomatic females of age group 15 to 35 years were selected at random for this pilot study.

 Materials and Methods



A total of 125 females in the age group 15 to 35 years were studied. Patients who were on thyroid medications or with thyroid disease were excluded. The study group included 61 nursing students, 62 professionals, and two housewives. Detailed history taking including family history of thyroid disease and thorough physical examination were done for all the subjects. Due to economical constraints, the laboratory investigations were limited to TSH, anti-TPO antibody, and ATG antibody estimations-done by chemiluminescence method.

 Results



Antibody positivity

Of the 125 subjects studied, 112 [89.6%] showed antibody positivity [Table 1]. Anti-TPO was the most prevalent antibody which was present in 107 subjects [86%], whereas ATG was positive in 70 subjects [56%].{Table 1}

Antibody positivity and family history

Of the 125 subjects, 18 [14%] had history of thyroid disorder in their first degree relatives and all of them had antibody positivity (both antibodies positive in 14 and only anti-TPO positive in four subjects).

Antibody positivity and thyromegaly

Thyromegaly was present in 51 individuals (41%), of which 48 subjects (94%) had thyroid autoantibody positivity and three (6%) without antibodies [Table 2].{Table 2}

Among the total 107 persons with anti-TPO positivity, 48 (45%) had thyromegaly and of the 70 subjects with ATG positivity, 29 (41%) had thyromegaly. The association between thyroid autoantibodies and thyromegaly were found to be statistically significant with P values 0.046 for anti-TPO and 0.001 for ATG and the relative risk for thyromegaly is 2.69 in case of anti-TPO and 7.6 in case of ATG positivity [Table 3] and [Table 4].{Table 3}{Table 4}

Two of the 125 subjects (1.6%) were detected to have hypothyroidism and one (0.8%) had hyperthyroidism. All three had both antibodies positivity.

 Discussion



The prevalence of thyroid autoantibodies in the general population reported by Williams is 5% to 20% for ATG and 8% to 27% for anti-TPO. [3] A survey by Amritha Institute, Cochin, in 2009 showed that thyroid function abnormalities were present in 19.6% of adult population and about 9.5% of the subjects had anti-TPO antibodies. [4] Our study shows a much higher proportion (90%) of cases with positive antibodies in the general population. A recent study on transplacental transfer of antithyroid antibodies conducted in our institution revealed a high prevalence of antibodies in babies born to mothers with positive thyroid antibodies. [5] Another study on the prevalence of autoantibodies in young men to assess whether there is a difference with gender is in progress in our institution.

Whether the presence of thyromegaly in subjects with positive antibodies is due to autoimmune thyroiditis can be established only by Fine Needle Aspiration Cytology (FNAC), which was not done in this study. Similarly, the presence of thyromegaly in subjects with negative antibodies can also be due to autoimmunity since autoimmune thyroiditis can present with negative antibodies also. [6]

In view of the higher prevalence of thyroid autoantibody positivity in these young women representing the general population of various economic strata, autoimmune thyroiditis should be considered as a major health problem. It is well known that the long-term effects of thyroid autoantibodies may result in thyroid dysfunction. As thyroid dysfunction can lead to antenatal and due to transmission of antibodies to the next generation-neonatal complications, the detection of antibodies is very important in pregnant patients. Thyroid autoimmunity is also a risk factor for pregnancy wastage and postpartum thyroiditis. [7]

A long-term follow-up by a longitudinal study of these subjects is absolutely essential to find out the possibility of developing thyroid dysfunction in future and thus the importance of detection of thyroid antibodies with asymptomatic state can be established.

 Acknowledgement



Dr. Aleyamma Mathew, Statistician, RCC, Trivandrum.

References

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2Vijayan S, Poulose J, Lalitha K, Poulose KP. Thyroid autoantibodies in pregnancy. Kerala Med J 2007;10:205-7.
3Kronenberg HM, Larsen PR, Melmed S, Polonsky K. Williams Textbook of Endocrinology. 11 th ed. Philadelphia: Saunders; 2008. p. 324-5.
4Unnikrishnan AG. Thyroid autoimmunity data from Kerala. Kerala Med J 2009;5:204-5.
5Sreedharan S, Poulose PK, Kesavan L, Indumathi K. Transplacental transfer of antithyroid antibodies a preliminary report. Thyroid Res Pract 2012;9:7-8.
6Anjali Sr, Sabeena S, Poulose KP. Correlation of thyroid autoantibodies and thyroid function in patients with autoimmune thyroiditis. Kerala Med J 2010;10:143-6.
7The American Thyroid Association Public Health Committee; Study of maternal hypothyroidism during pregnancy. Thyroid 1999;9:971-2.