Iodine status of adults in Taiwan 2005-2008, 5 years after the cessation of mandatory salt iodization.
OBJECTIVE
Iodine deficiency causes a broad spectrum of disorders across all ages. Mandatory salt iodization in Taiwan successfully reduced the goiter rate from 21.6% to 4.3% in schoolchildren surveyed in 1971. The program continued until 2003 when salt iodization was changed from mandatory to voluntary. The purpose of this study was to investigate the iodine status of Taiwanese individuals after the change in the iodine policy.


METHODS
Urinary iodine (UI) was measured in samples from adults in the Nutrition and Health Survey in Taiwan 2005-2008.


RESULTS
The median UI level was 100 μg/L, and the percentage of populations with UI levels below 100 μg/L and 50 μg/L was 50.1% and 15.1%, respectively, indicating that the iodine status was borderline adequate. Men had a higher UI level than women (102 μg/L vs. 98 μg/L, p = 0.003), and older individuals (age > 60 years) had a lower UI level than younger people, particularly in women. The iodine status of the population < 50 years was sufficient, but it was insufficient in older groups. Mild iodine insufficiency was noted in all areas of Taiwan except the Southern area and Penghu islands, with the lowest UI level of 79 μg/L in the Mountain area. Although the UI level of women of childbearing age (19-44 years) was 103 μg/L, there may be a risk of iodine deficiency during pregnancy.


CONCLUSIONS
The iodine nutrition of the Taiwanese population in 2005-2008 was borderline adequate, with insufficiency in some subgroups. Further monitoring of the iodine status is necessary.
Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan. Electronic address: tang8228@gmail.com.
Kam-Tsun
KT
Tang
Department of Medicine, Yangming Branch, Taipei City Hospital, Taipei, Taiwan.
Fan-Fen
FF
Wang
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Wen-Harn
WH
Pan
Division of Endocrinology and Metabolism, Shuang Ho Hospital, Taipei, Taiwan.
Jiunn-Diann
JD
Lin
Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan.
Ging-Shing
GS
Won
Division of Hematology and Oncology, Taipei Medical University Hospital, Taipei, Taiwan.
Wing-Keung
WK
Chau
Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan.
Hong-Da
HD
Lin
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Yao-Te
YT
Hsieh
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006042:Goiter / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D007455:Iodine / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D011247:Pregnancy; D017678:Sex Distribution; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*; D013624:Taiwan; D013961:Thyroid Gland / Q000187:drug effects; D055815:Young Adult
D017673:Sodium Chloride, Dietary; D007455:Iodine
Taiwan; iodine; iodized salt; nutrition survey; thyroid gland