EPIDEMIOLOGICAL CHARACTERISTICS OF SUBCLINICAL HYPOTHYROIDISM
Authors:   Department of Endocrinology, Avicenna Tajik State Medical University, Dushanbe, Republic of Tajikistan, Inoyatova Nigina , Pirmatova Makhina ,   Department of Endocrinology, Avicenna Tajik State Medical University, Dushanbe, Republic of Tajikistan, Samieva Shakhnoza ,   Department of Endocrinology, Avicenna Tajik State Medical University, Dushanbe, Republic of Tajikistan,   Medical Center of the Executive Office of the President of the Republic of Tajikistan, Dushanbe, Republic of Tajikistan
Published: December 2024

Objective: To study the prevalence of subclinical hypothyroidism (SH) in the middle-aged and elderly population of Dushanbe.
Methods: The results of clinical, instrumental examination of the thyroid gland (TG), and its hormonal function assessment were analyzed in 5,857
people who visited endocrinologists for consultation or treatment in 2018-2022. Among the examined patients, there were 3765 women (64.3%)
and 2092 men (35.7%). Their age ranged from 35 to 65 years, averaging 40.2±1.2 years. In addition to clinical examination and thyroid palpation,
all respondents underwent ultrasound examination of the TG, blood tests for thyroid stimulating hormone (TSH), free thyroxine (free T4) and
triiodothyronine (free T3), and antibodies to thyroid peroxidase (AB to TPO).
Results: TSH levels were elevated in 1,743 (29.8%) respondents and decreased in 373 (6.3%), among which 278 were women (7.4%) and 95 men
(4.5%). Normal range of TSH was found in 3,741 (63.9%) of those examined. SH was detected in 1,279 cases (21.84%), and manifest hypothyroidism
(MH) was found in 464 of examined patients (7.92%); the latter being 2.6 times more common in females (n=334; 71.9%) than in males (n=130; 28.1%)
(p<0.05). The same picture was observed in the cohort of respondents with SH, where there were 2.3 times more women (n=887; 69.4%) than men
(n=392; 30.6%) (p<0.05). The average age of men and women with SH did not differ significantly, being 35.5±0.5 years and 37.8±0.3 years, respectively
(p>0.05). Among the cohort with SH, thyroid ultrasound examination revealed increased echogenicity of the TG in 26.2%, decreased echogenicity in
48.0%, and normal echogenicity in 25.8% of cases. Among all examined patients, diffuse Grade I and II enlargement of the TG was found in 2,577
(43.99%), nodular goiter – in 1528 (26.1%), and mixed goiter – in 1956 (33.4%) observations. In the group of respondents with SH, women had diffuse enlargement of the TG 2.5 times more often (25.3% versus 10.2%; p<0.05), 3.6 times more often in nodular goiter (16.5% versus 4.6%; p<0.05) and
2.5 times more often in mixed goiter (23.8% versus 9.6%; p<0.05) compared to men. The absence of changes in the size and structure of the TG was
observed 1.7 times more often in males (n=80; 6.3%) than in females (n=48; 3.8%) without significant difference (p>0.05). The level of AB to TPO was
higher in women than in men (p<0.05), while there were no statistically significant differences in the level of TSH and thyroid hormones in the blood
serum between males and females. A direct correlation was found between the TSH and the AB to TPO levels in the examined cohort (r=0.26325;
p<0.05).
Conclusion: The prevalence of SH in Dushanbe, based on the data from the examined cohort, was 21.8%; most commonly the disease started in young
age, mainly in active females of working age. Ultrasound examination revealed significant changes in the structure of the TG in 70.1% of all examined
patients, and in 89.9% of patients with SH. It is of interest to continue investigation of SH prevalence in the population of highland areas, as well as the
causes and risk factors associated with the development of SH.
Keywords: Subclinical hypothyroidism, thyroid-stimulating hormone, prevalence, thyroid gland, nodular and mixed goiter.