Ann. Pak. Inst. Med. Sci. 2010; 6(2): 101-106

Objectives: To find the prevalence of thyroid disorders in association with age and sex
Study Design: Cross sectional descriptive study.
Setting and duration of study: Chemical pathology laboratory Benazir Bhutto Hospital from September 2004 to February 2005.
Materials and Methods: The study comprised of 139 subjects including 115 females and 24 males from 5-80 years of age. History and physical examination of each patient was taken according to the predesigned Performa. The thyroid profile was tested by ELISA tech to find out the values of TSH, T4, T3.
Results: It was found that the thyroid disorders were 5 times more common in females than in males. Primary hypothyroidism was 4.5 times more common in females. Hypothyroidism was twice as compared to hyperthyroidism (2.25 times). The occurrence of thyroid disorders in order of decreasing frequency was primary hypothyroidism 63.3%, primary hyperthyroidism 28.1%, subclinical hypothyroidism was 4.4%, secondary hypothyroidism 1.4%, subclinical hyperthyroidism 1.4%, secondary hyperthyroidism 0.7% and T3 toxicosis 0.7%. The study also shows that young adult in the range of 16-40 years are more likely to suffer from thyroid illness.
Conclusion: Thyroid disorders are 5 times more common in females than males. Primary hypothyroidism is the most common thyroid disorder followed by primary hyperthyroidism. Hypothyroidism is twice as common as hyperthyroidism. Sub clinical hypothyroidism is found in 4.3% predominantly in females. T3 toxicosis was found in 0.7% predominantly in male subject. Secondary thyroid disorders are much less common than primary disorders. Younger adults in the age of 16-40 years are more susceptible to thyroid disorders.
Keywords: Hypothyroidism, Hyperthyroidism, Subclinical hypothyroidism, Subclinical hyperthyroidism.

Introducation

Thyroid dysfunctions are common endocrine problems. Hyperthyroidism and Hypothyroidism together account for considerable morbidity in USA and other countries.¹
The total prevalence of these disorders in life time is estimated to be 5-10%.² An estimated 27 million Americans³ have thyroid disease, and more than half are undiagnosed.⁴ Often misdiagnosed, misunderstood, and frequently overlooked thyroid disease affects almost every aspect of health. Most of them remain undiagnosed as the clinical assesment alone lacks both sensitivity and specificity and can suspect only 40% of overt thyroid disorders. Only the biochemical test, can confirm the diagnosis.⁵
The normal thyroid gland controls the body metabolism, growth, development and maintenance of the internal environment. Thyroid is an important endocrine gland and elaborates two key metabollic hormones thyroxine (T4) and tri-iodo thyronine (T3). The later is biologically more active and is produced mainly by the coversion of prohormone (T4) to (T3) by enzyme 5-deiodonase in the peripheral tissues mainly in liver and kidney.⁴ Both these hormones are under the contol of thyroid stimulating hormone (TSH) of anterior pitutary gland which in turn is controlled by thyrotrophin releasing hormone (TRH) from hypothalamus. Nature has established almost a perfect method to regulate the amount of hormones to be secreted by the thyroid gland. However thyroid disorders disrupt this mechanism.
The spectrum of thyroid disorders range from a condition of hypothyroidism (under active) to hyperthyroidism (over active.)The biochemical and clinical classification of thyroid disorders include primary disorders due to thyroid gland dysfunction itself such as primary hypothyoidism, primary hyperthyroidism. Secondary disorders due to pituatary gland disorder include secondary hypothyroidism and secondary hyperthyroidism. Tertiary disorders due to hypothalamic diseases include tertiary hypo and hyperthyroidism.
Diagnosis of subclinical disorders, which is mainly based on elevation (TSH>4.5smU/L) or supression of TSH (<0.2mU/L) level laeding to hypothyroidism and hyperthyrodism respectively, with minor or no clinical findings and T3 and T4 levels within the normal range.⁶ T3 toxicosis due to mainly increased T3 level without increased T4 level.⁷ Euthyroid sick syndrome is the term used for non-thyroidal illness prbably as a result of adaptation to new catabolic state not due to thyroid illness itself.⁸
Thyroid disorders may occur at any age and in both genders, but its occurrence is different in different geographical areas and in different age and sex groups.⁹
Therefore a study was planned to find the prevalence of various thyroid disorders in different age and sex groups in population of Rawalpindi and Islamabad.