The current study findings revealed that a considerable percentage of the participants had thyroid dysfunctions, (14%) had lower TSH levels which mean hyperthyroidism and (12%) had higher TSH levels which means hypothyroidism. Literature has also supported high prevalence of thyroid dysfunction among patients in developed as well as developing countries. It has been estimated that about 42 million people in India suffer from thyroid dysfunction, in addition, studies from Mumbai have suggested that congenital hypothyroidism is common in India, the disease occurring in 1 out of 2640 neonates, when compared with the worldwide average value of 1 in 3800 subjects (11). Hypothyroidism is a commonly prevailing disorder in adult Indian population as well (12). Moreover, a recent study conducted in Iran reported higher incidence rate of thyroid disorders than previous studies (13). Similarly, According to a survey, which was conducted in Whickham in order to determine the prevalence of thyroid dysfunction in the community it was revealed that thyroid dysfunction affects 1–2% adult population of the Great Britain (14).
Likewise, in the current study, researcher found a significant association between age and thyroid dysfunction (p-value 0.02). Individuals with age (31–54 years) were more prone to thyroid dysfunction compare to younger individuals with age (21–30 years). Similar finding was found in another study which was conducted in Greece, in which the author found a strong association between aging and decrease TSH and T3 levels while serum FT4 levels were normal (15). In addition, smoking was found to have a significant relation with thyroid dysfunction (p-value 0.016). None of the individuals with normal TSH level were smokers, 2 persons of the patients with higher TSH level were smoking and 1 person of the patient with lower TSH level was smoking. Literature also supports the current findings of the study suggesting that smoking cessation is effective in primary, secondary and tertiary prevention of thyroid disorders (16). On the contrary, another study conducted by Cari M. Kitahara found that cigarette smoking is associated with reduced risks of papillary thyroid cancer and, probably, follicular thyroid cancer (17).
Furthermore, this study did not reveal any significant relation between family history and thyroid dysfunctions, which is differing from the literature that indicates strong association between family history and thyroid dysfunctions. In a multicenter cohort study which was conducted in United Kingdom about half of all the subjects reported a family history of thyroid dysfunction (18).
In addition to being the first report from Afghanistan, there were a few limitations of this study, mainly the TSH only approach which could lead to potential confounders. The data of this study is limited to those individuals who visited FMIC; thus limiting the generalizability of the results. Furthermore, the use of questions regarding family history from the subjects may have possible recall bias.
The findings recommend screening and investigation for thyroid dysfunctions in Afghan population at high risk for thyroid disorders (smokers, elder people, especially pregnant women and neonates as neonatal thyroid disorders cause irreversible complications).