[Show abstract][Hide abstract] ABSTRACT: To determine the factors that influence the development of abnormal thyrotropin (TSH) level in an euthyroid population.
We conducted a follow-up study in 3 communities with different iodine status. Of the 3403 euthyroid subjects at baseline screened in 1999, 80.1% (n = 2727) was visited and sampled in 2004 for measuring TSH, thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb).
Iodine status in the 3 communities were stable. Decreased TSH level (< 0.3 mU/L) developed in 2.5% (n = 68) of sampled subjects, while raised TSH level (> 4.8 mU/L) in 2.4% (n = 64). A logistic analysis showed that risk factors for developing decreased TSH level included positive conversion of TPOAb (OR = 5.5), positive TPOAb both in 1999 and in 2004 (OR = 4.0), positive TgAb in 2004 (OR = 3.7) and TSH < 1.0 mU/L in 1999 (OR = 2.6). Risk factors involved in developing raised TSH level included iodine status of Zhangwu community (OR = 4.1), iodine status of Huanghua community (OR = 3.9), positive TgAb in 2004 (OR = 3.7), positive TPOAb both in 1999 and 2004 (OR = 3.6), positive conversion of TPOAb (OR = 2.7) and TSH > 1.9 mU/L in 1999 (OR = 2.6).
Exposure to long-term iodine excess imposes danger of developing hypothyroidism. The risk will be even higher when exposing to iodine adequacy after correction of iodine deficiency. An interval between 1.0 and 1.9 mU/L of TSH level was optimal with the least probability of developing abnormal TSH level.
No preview · Article · May 2009 · Zhonghua nei ke za zhi [Chinese journal of internal medicine]
[Show abstract][Hide abstract] ABSTRACT: To investigate the prevalence of gestational transient thyrotoxicosis (GTT) and analyze the cause of thyrotoxicosis encountered in this period.
An epidemiologic survey in ten hospitals in Shenyang was performed and 534 pregnant women during the first trimester of pregnancy filled questionnaire, received physical examination and had serum thyroid-stimulating hormone (TSH), free T(4) (FT(4)), free T(3) (FT(3)), thyroid peroxidase antibody (TPOAb), thyrotrophin receptor antibody (TRAb), and human chorionic gonadotrophin (hCG) tests.
(1) The total prevalence of thyrotoxicosis was 9.75% (52/534) in the first trimester and the prevalence of GTT was 7.86%, which accounted for 80.77% of the thyrotoxicosis encountered in this period. A total of 88.89% of the overt GTT showed only elevated FT(3) level. (2) The level of serum hCG increased gradually in the first trimester. The medians of hCG were 25 300, 85 220 and 81 780 IU/L 6, 8 - 10 and 12 weeks after gestation, respectively (P = 0.000). The medians of serum TSH were 1.45, 1.10 and 0.84 mIU/L 6, 8 - 10 and 12 weeks after gestation, respectively (P < 0.01). (3) When serum hCG was more than 50 000 IU/L, the prevalence of GTT increased obviously. When serum hCG was between 80 000 IU/L and 110 000 IU/L, subclinical GTT increased significantly. When serum hCG was more than 110 000 IU/L, overt GTT increased significantly. Correlation analysis showed that serum hCG was related negatively with TSH (r = -0.402, P = 0.000) and positively with FT(3) (r = 0.165, P = 0.000), but not related with FT(4).
The prevalence of GTT is 7.86% in the first trimester and it is the main cause of thyrotoxicosis found in the first trimester, accounting for 80.77% of all the causes. The serological characteristic of overt GTT is mainly the elevation of serum FT(3) level. Serum hCG level is related with the severity of GTT.
No preview · Article · Jan 2009 · Zhonghua nei ke za zhi [Chinese journal of internal medicine]
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of cigarette smoking on thyroid gland volume, thyroid function and thyroid autoantibodies in the areas with different iodine intakes.
A cross-sectional epidemiological study in Panshan (mild iodine-deficient area), Zhangwu (more than adequate iodine intake area) and Huanghua (iodine-excessive area) was conducted in 3761 subjects in 1999.80.2 % of them were followed up in 2004. Questionnaires, thyroid function, thyroid autoantibodies, urinary iodine concentration,and thyroid B ultrasound were performed.
The prevalence of goiter was higher in smokers than in non-smokers (15.1% vs. 11.5%, P< 0.05). The average thyroid volume was higher in smokers with phenomenon more obvious in Panshan and Huanghua areas. Data from logistic analysis showed that smoking cigarette was an independent risk factor of goiter. There was no difference in serum TSH and Tg level between smokers and non-smokers. The positive rate of TPOAb (>100 IU/ml) was higher in smokers than in non-smokers(10.8% vs. 9.0 % , P <0.05) and was especially obvious in Huanghua area. Smoking was a independent risk factor of increasing positive rate of TPOAb. During the prospective observation,it was found that the incidence of positive TPOAb(>,100 IU/ml) was 7.4% in the subjects that were from non-smokers turning to smokers and 2.9% in those whose smoking behavior did not change. Logistic analysis indicated that the shifting from non-smoking to smoking was independent risk factor for the increase on high incidence of positive TPOAb.
Smoking cigarette was a independent risk factor of goiter. Smoking was also a risk factor of increasing TPOAb positive rate. Shifting from not smoking to smoking was an independent risk factor of increasing high incidence of positive TPOAb.
No preview · Article · Feb 2007 · Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi