More than adequate iodine may increase subliminal hypothyroidism/Autoimmune Thyroiditis

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Eur

J Endocrinol. 2011 Mar 28. [Epub ahead of print]

More

Than Adequate Iodine Intake May Increase Subclinical Hypothyroidism and

Autoimmune Thyroiditis: A Cross-Sectional Study Based on Two Chinese

Communities with Different Iodine Intake Levels.

Teng

X, Shan

Z, Chen

Y, Lai Y,

Yu J,

Shan

L, Bai X,

Li Y,

Li N,

Li Z,

Wang

S, Xing

Q, Xue H,

Zhu

L, Hou X,

Fan

C, Teng

W.

X Teng, Department of

Endocrinology, First Affiliated Hospital of China Medical University, Shenyang,

China.

Abstract

Abstract

Objective: With the introduction of iodized salt worldwide, more and more

people have been in the situation with more than adequate iodine intake levels

with median urinary iodine excretion (MUI 200-300μg/L) or excessive iodine

intake levels(MUI >300μg/L).The objective of this study was to explore the

associations between more than adequate iodine intake levels and the

development of thyroid diseases (e.g., thyroid dysfunction, thyroid

autoimmunity, and thyroid structure) in two Chinese populations. Design: A

population-based cross-sectional study was conducted in two areas in which

people have different levels of iodine intake (Rongxing, MUI 261 μg/L;

Chengshan, MUI 145 μg/L). Random samples of 3813 individuals were recruited.

Thyroid hormones, thyroid autoantibodies in serum, and iodine levels in urine

were measured. B-mode ultrasonography of the thyroid also was performed for

each participant. Results: The prevalence of subclinical hypothyroidism was

significantly greater for subjects who live in Rongxing than those in Chengshan

(5.03% vs. 1.99%, P < 0.001). The prevalences of positive anti-thyroid

peroxidase antibody (TPOAb) and positive anti-thyroglobulin antibody (TgAb)

were significantly higher for subjects in Rongxing than those in Chengshan

(TPOAb: 10.64% vs. 8.4%, P = 0.02; TgAb: 10.27% vs. 7.93%, P = 0.01). The increase

of thyroid antibodies was most pronounced in the high concentrations of TPOAb

(TPOAb: ≥500 IU/ml) and low concentrations of TgAb (TgAb: 40-99 IU/ml) in

Rongxing. Conclusions: More than adequate iodine intake could be a public

health concern in terms of thyroid function and thyroid autoimmunity in the

Chinese populations.

PMID: 21444648 [PubMed

- as supplied by publisher]