RESUMO
Objective To clarify the effect of iodine intake on serum thyroglobulin (Tg). Methods A 5-year prospective study was conducted in the 3 different iodine intake areas in China [Panshan (miht deficiency) ,Zhangwu (more than adequate) and Huanghua (excess)]. A total of 3 099 people with normal serum levels of Tg in 1999 were followed and 2 448 of these participants were feasible to be observed in 2004 and included in the present study. The serum levels of Tg, thyraglobulin antibody(TgAb), thyroid peroxidase antibody(TPOAb) and TSH, thyroid volume, family and personal histories of thyroid diseases were measured and inquried. The general linear model (GLM) was used to explore the determinants of Tg. Results Among the study population at baseline, serum Tg were significantly different in three areas [7.5 (4.4-13. 1) μg/L at Panshan, 6.8 (3.6-11.2)μg/L at Huanghua, 5.9 (3.2-10.7) μg/L at Zhangwu, P<0.01]. They were associated with age, sex and the rate of positive TgAb, abnormal thyroid volume, abnormal TSH and positive personal history of thyroid diseases, in order to control the effects of confounding factors, the data from 1856 subjects with thyroid-related indexes all in normal range and without personal history of thyroid diseases were analyzed to clarify the effect of iodine intake on Tg. The serum Tg among three areas were significantly different in both 1999 and 2004, they were all increased in 5 years with significant augment (△ Tg) among the three areas[3.1 (-0.2-8.0) μg/L at Panshan, 3.5 (0.5-9.0)μg/L at Huanghua vs 2. 5(0.3-6.1) μg/L at Zhangwu,P<0.01]. The GLM analysis revealed that age, Tg and TSH levels at baseline were the determinants of △Tg in addition to iodine intake. Conclusion Iodine intake is a dominant determinant of serum Tg. Age and TSH should also be considered while indicating iodine intake by serum Tg.
RESUMO
<p><b>OBJECTIVE</b>To investigate the prevalence of thyroid diseases in a community which did not use iodized salt.</p><p><b>METHODS</b>The survey was conducted in Panshan, Liaoning Province. 1 103 inhabitants aged 14 years or more attended the examinations, which included questionnaire, physical examination and serum analysis. Iodine in the urine and thyroid B ultrasound examination were also conducted.</p><p><b>RESULTS</b>The prevalence of overt hyperthyroidism and hypothyroidism was 16.3 per thousand and 2.7 per thousand, respectively. Subclinical hyperthyroidism and hypothyroidism were detected in 37.2 per thousand and 9.1 per thousand of the subjects, respectively. Serum autoantibodies to thyroid were detected in 10.9% of the entire population. The prevalence of goiter was 20.7% (diffuse goiter 16.8% and nodular goiter 3.9%).</p><p><b>CONCLUSION</b>In the iodine deficient areas, perhaps autoimmununization is not only related to the development of goiter but is also the main cause of subclinical hyperthyroidism and hypothyroidism.</p>