Prevalence of thyroid dysfunction with adequate and excessive iodine intake in Hebei Province, People's Republic of China.
OBJECTIVE
To explore (i) the prevalence of thyroid dysfunction in populations with adequate and excessive iodine intakes and (ii) the effect of iodine exposure on the prevalence of thyroid dysfunction.


METHODS
Cross-sectional study was conducted in Hebei in 2010. The population was classified as having adequate or excessive iodine intake according to the iodine concentration in drinking water. Demographic information was collected by questionnaire. Levels of serum thyroid hormones, thyroid autoantibodies and iodine in drinking water and urine were measured.


METHODS
Villages with adequate or excessive drinking water iodine in Hebei Province, People's Republic of China.


METHODS
A total of 854 men and women aged 20-50 years who had lived in the surveyed areas for over 5 years, including 348 from the adequate iodine area (AIA) and 506 from the excessive iodine area (EIA).


RESULTS
Median urinary iodine concentration was 185 μg/l in AIA and 1152 μg/l in EIA. The prevalence of thyroid dysfunction in AIA was 10.3%, which included 1.1% with hypothyroidism and 8.1% with subclinical hypothyroidism; and 20.6% in EIA, which included 3.6% with hypothyroidism and 13.6% with subclinical hypothyroidism. The positive rates of thyroglobulin antibody were 16.1% in AIA and 11.9% in EIA; the positive rates of thyroperoxidase antibody were 20.7% in AIA and 16.4% in EIA.


CONCLUSIONS
Excessive iodine intake may lead to increased prevalence of biochemical thyroid dysfunction, especially biochemical hypothyroidism. This is not related to an increase in prevalence of thyroid antibodies. Women are more susceptible to iodine excess.
1Department of Nutrition and Food Science,School of Public Health,Tianjin Medical University,Tianjin 300070,People's Republic of China.
Long
L
Tan
1Department of Nutrition and Food Science,School of Public Health,Tianjin Medical University,Tianjin 300070,People's Republic of China.
Zhongna
Z
Sang
2Department of Sanitary Chemistry,School of Public Health,Tianjin Medical University,Tianjin,People's Republic of China.
Jun
J
Shen
3Centers for Disease Control and Prevention in Cangzhou City,Cangzhou,People's Republic of China.
Hua
H
Liu
1Department of Nutrition and Food Science,School of Public Health,Tianjin Medical University,Tianjin 300070,People's Republic of China.
Wen
W
Chen
1Department of Nutrition and Food Science,School of Public Health,Tianjin Medical University,Tianjin 300070,People's Republic of China.
Na
N
Zhao
4Chengyang Workstation of Health Supervision and Diseases Control,Qingdao,People's Republic of China.
Wei
W
Wei
5Department of Clinical Nutrition,Binzhou Medical University Hospital,Binzhou,People's Republic of China.
Guiqin
G
Zhang
1Department of Nutrition and Food Science,School of Public Health,Tianjin Medical University,Tianjin 300070,People's Republic of China.
Wanqi
W
Zhang
D000328:Adult; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D060766:Drinking Water / Q000032:analysis; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000032:analysis; D007455:Iodine / Q000008:administration & dosage* / Q000009:adverse effects* / Q000652:urine; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011795:Surveys and Questionnaires; D013954:Thyroglobulin / Q000032:analysis; D013959:Thyroid Diseases / Q000453:epidemiology*; D016482:Urinalysis
D060766:Drinking Water; D013954:Thyroglobulin; D007455:Iodine; D007453:Iodide Peroxidase
Autoantibody; Excessive iodine; Hypothyroidism; Thyroid hormone