Session: SUN 432-458-Thyroid Autoimmunity
Poster Board SUN-447
Objective To determine the current prevalence of thyroid disorders in China and to assess the association of serum TSH and antithyroid antibodies with iodine intake.
Design and setting A cross-sectional study was conducted in ten cities in China between May, 2010 and May, 2011.
Participates A total of 15,008 randomly chosen subjects from one or two communities in each city were studied. Iodine concentration in urine, from a total of 80 school-age children from each city, was also tested.
Main Outcome Measures Palpation and B-mode ultrasonography of the thyroid were performed, and urine iodine levels and serum levels of TSH, TPOAb and TgAb were measured in all participants. FT4 and FT3 were measured in individuals who had abnormal TSH concentrations.
Results The prevalence of overt hypothyroidism, subclinical hypothyroidism, overt hyperthyroidism as well as positive TPOAb and TgAb were significantly higher in regions with excessive iodine intake than in regions with adequate iodine intake. The serum TSH levels were notably higher than reported previously. The median TSH level was 2.40 mIU/liter (0.76–6.92 mIU/liter) in the reference population. Median of TSH from a subpopulation (n=2502) was found to increase over time from 1.17 mIU/liter in 1999 to 1.96 mIU/liter in 2011 (P>0.001) with a change in the median urine iodine (MUI) from 143.4 μg/liter to 194.5 μg/liter. The prevalence of positive thyroid antibodies also rose from 4.9% in 1999 to 7.2% in 2011 for TPOAb (P=0.04) and from 5.5% to 8.4% for TgAb (P=0.02).
Conclusions More than adequate iodine intake was found to be associated with increased prevalence of most thyroid disorders. The notably high TSH levels detected in the Chinese population may be related to long-term iodine fortification and aggravated thyroid autoimmunity. The significance of high TSH values in Chinese population merits further study.
Nothing to Disclose: WT, LC, XL, CL, ZS, BS, LS, NT, JW, SW, JZ, XT, XY, YL, CL, WW, JM, CF
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