Evaluation of the iodine status in breastfeeding women living in various iodine consumption areas of Voronezh region in women

BACKGROUND: Ensuring adequate iodine intake in lactating women is critically important for infant brain development. The WHO classifies them as a high-risk group for developing iodine deficiency disorders (IDD). Previously, we identified mild iodine deficiency in pregnant women in the Voronezh region. AIM: To assess the thyroid status and iodine intake levels in lactating women residing in districts of the Voronezh region with varying levels of iodine consumption among women. MATERIALS AND METHODS: A cross-sectional cohort study of 100 lactating women (September–October 2024) included a questionnaire, physical examination, and measurement of thyroid-stimulating hormone (TSH), anti-thyroid peroxidase antibodies (Anti-TPO), selenium, and zinc in blood, urinary iodine (cerium-arsenite method), and breast milk iodine (mass spectrometry), as well as rapid testing of salt for iodine. RESULTS: Iodized salt was used by 17% of households; 16% of women used it regularly; iodine supplements were taken by 12%; iodine-rich foods were consumed by 9%. The median urinary iodine concentration (mUIC) was 62.9 μg/L (normal ≥100 μg/L). The median breast milk iodine concentration was 37.77 μg/L (normal 100–200 μg/L). The median TSH was 1.425 mIU/L; thyroid dysfunction was found in 7%; Anti-TPO positivity in 14%. Selenium and zinc levels were in the lower tertile of normal. A moderate positive correlation was found between urinary and breast milk iodine (ρ=0.48; p=0.032). CONCLUSION: Lactating women in the Voronezh region exhibit pronounced iodine deficiency and critically low breast milk iodine content, posing a threat to infant cognitive development. Systemic iodine prophylaxis measures are urgently needed.