Antithyroperoxidase and antithyroglobulin antibodies in a five-year follow-up survey of populations with different iodine intakes.
OBJECTIVE
In a follow-up study, we determined the prevalence, incidence, and natural course of positive antithyroperoxidase antibodies (TPOAbs) and antithyroglobulin antibodies (TgAbs) in the general population and examined the influences of iodine intake.


METHODS
The study was conducted in Panshan, Zhangwu, and Huanghua, regions with mildly deficient, more than adequate, and excessive iodine intake, respectively. Of the 3761 unselected subjects who were enrolled at baseline, 3018 participated in the 5-yr follow-up study. Serum TSH, TPOAb, and TgAb levels were measured.


RESULTS
Among subjects in Panshan, Zhangwu, and Huanghua, the prevalence of positive TPOAbs was 11.23, 11.83 and 12.02%, respectively, whereas 11.23, 11.17, and 11.26% of subjects were TgAb positive, respectively. In the older population (> or =45 yr), TgAb-positive individuals were more frequent in Huanghua than Panshan and Zhangwu (P < 0.05). The 5-yr cumulative incidence of positive TPOAb was 2.08, 3.84, and 2.84% in Panshan, Zhangwu, and Huanghua, respectively, whereas 2.91, 3.64, and 5.07% of subjects were TgAb positive, respectively (P < 0.05), corresponding to the increase in iodine intake. Subjects who were TPOAb and/or TgAb positive at baseline developed thyroid dysfunctions more frequently than those without antibodies (14.44 vs. 3.31%, P < 0.01); their incidence of elevated TSH levels was 1.32, 8.46, and 15.38% in Panshan, Zhangwu, and Huanghua, respectively (P < 0.05).


CONCLUSIONS
Subjects who were TPOAb and TgAb positive at baseline developed thyroid dysfunctions more frequently than seronegative subjects. High iodine intake was a risk factor for developing hypothyroidism in antibody-positive subjects. A constant exposure to excessive iodine intake increased the incidence of positive TgAb.
Li
Yushu
Y
Department of Endocrinology and Metabolism, and the Institute of Endocrinology, First Affiliated Hospital, China Medical University, no.155 Nanjing Bei Street, Heping District, Shenyang, China.
Teng
Di
D
Shan
Zhongyan
Z
Teng
Xiaochun
X
Guan
Haixia
H
Yu
Xiaohui
X
Fan
Chenling
C
Chong
Wei
W
Yang
Fan
F
Dai
Hong
H
Gu
Xiaolan
X
Yu
Yang
Y
Mao
Jinyuan
J
Zhao
Dong
D
Li
Jia
J
Chen
Yanyan
Y
Yang
Rong
R
Li
Chenyang
C
Teng
Weiping
W
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D013972:Thyrotropin / Q000097:blood
D001323:Autoantibodies; C006606:anti-thyroglobulin; D013972:Thyrotropin; D007455:Iodine; D007453:Iodide Peroxidase