Iodine status and thyroid function in Fergana region
Received: 2026-05-24
Published: 2026-09-30
Abstract
Background. Iodine deficiency is the main preventable cause of thyroid disorders. Despite salt iodization, iodine status in Uzbekistan remains uneven, and the relationship between urinary iodine and thyroid function in the Fergana Valley has been poorly studied.
Aim. To assess iodine status and thyroid function in middle-aged men in six areas of Fergana region and to evaluate the association between them.
Materials and methods. From May 2025 to August 2026, 175 men aged 36–58 years were examined in Beshariq, Dang‘ara, O‘zbekiston, Quva and Yozyovon districts and Fergana city using a purposive (non-random) sample. Urinary iodine concentration (UIC) was measured in a single spot morning urine sample by the Sandell–Kolthoff method, TSH, free T4 and free T3 by enzyme immunoassay, and thyroid ultrasound was performed.
Results. Median UIC in the whole sample was 85 µg/L; 111 men (63.4%) had UIC below 100 µg/L. No statistically significant difference in the frequency of iodine deficiency was found between areas (58.6–70.4%; p=0.95). UIC correlated strongly and negatively with TSH (r=-0.88) and positively with free T4 (r=0.69; p<0.001). Hypothyroidism was found in 9.4% of men with UIC ≥100 µg/L, in 83.5% with UIC 50–99 µg/L and in 100% with UIC <50 µg/L; the proportion of overt hypothyroidism was 0%, 16.5% and 80.8%, respectively. Each 10 µg/L increase in UIC reduced the odds of hypothyroidism 3.2-fold (OR=0.31; p<0.001). The free T3/free T4 ratio increased with iodine deficiency (p<0.001), while free T3 remained unchanged.
Conclusion. Insufficient iodine status was frequent in the studied sample and was associ-ated with reduced thyroid function in a dose-dependent manner. Men with UIC below 50 µg/L represent a high-risk group for overt hypothyroidism. Because the sample was purposive, the proportions reported should not be interpreted as prevalence estimates for the regional population.
Keywords
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