Geographical Patterns and Determinants of Selenium Deficiency in Tibet: A Cross-Sectional Study Based on Urinary Selenium Analysis

Selenium is an essential micronutrient, yet its deficiency poses severe health risks, including Kashin-Beck disease, a debilitating disorder endemic to selenium-deficient regions like Tibet. Despite the known risks, the extent and drivers of selenium deficiency in Tibetan populations remain poorly characterized. Here, we present the first large-scale assessment of urinary selenium levels across Tibet, based on 637 systematically collected samples, revealing an average concentration of 7.71 μg/L, far below adequate thresholds. Dietary patterns, particularly reliance on the red meat and vegetable diet, emerged as the dominant factor influencing selenium levels, while aging was associated with a marked decline in selenium status. Geographical factors were found to exert indirect but significant effects. These findings highlight critical selenium deficiencies among Tibetan residents and emphasize the urgent need for targeted interventions, including the introduction of selenium-enriched foods, to mitigate health risks—especially for older populations most at risk.