To evaluate the iodine nutritional status and thyroid stimulating hormone (TSH) level in adult Tibetan of Qinghai Province after Universal Salt Iodization, to analyze the change rules and provide guidance for adult iodine supplementation in Tibetan areas.

Guoluo Prefecture and Hainan Prefecture of Qinghai Province were chosen in 2012 and 2013, residents over 20 years old were extracted using stratified cluster sampling method, fasting morning urine 5 ml was collected, arsenic cerium catalytic spectrophotometry method was used to determinate the urinary iodine level. Morning fasting venous blood 5 ml was collected, serum TSH level was detected with electrochemiluminescence immunoassay. And the factors influencing urinary iodine levels were analyzed using logistic regression analysis.

The number of adult Tibetan urine and blood samples was both 936. The median of urine iodine was 220.9 μg/L, the median of serum TSH was 1.92 mU/L. There were downward trends of urine iodine and serum TSH levels with increasing age. The iodine level of 20-45 years old was greater than the appropriate amount. The median of women's urinary iodine was 1.96 mU/L, men's was 1.43 mU/L, female's was higher than that the male's (U =-2.207, P < 0.01). The results of regression analysis indicated that serum TSH levels were closely related to urinary iodine (OR = 1.046, P < 0.05).

The iodine nutrition of adults over 45 years old is more than the sufficient quantity in Qinghai Tibetan areas, which may affect the level of serum TSH level. Young women should regularly inspect their thyroid function and urinary iodine level.

Urine; Iodine; Thyroid stimulating hormone; Tibetan