A dietary iodine questionnaire: correlation with urinary iodine and food diaries.
OBJECTIVE
It has been difficult to determine the sources of U.S. dietary iodine. This study was designed to validate a self-administered questionnaire about dietary iodine sources.


METHODS
We constructed a questionnaire to assess iodine intake in 46 healthy Boston-area adult volunteers. Questionnaire information was correlated with subjects' 24-hour food diaries. Spot morning urine cotinine (a metabolite of nicotine from cigarette smoking) and iodine concentrations were measured.


RESULTS
91% of 46 subjects were women [mean (+/- SD) age of 38 (+/- 10) years]. Information from 24-hour food diaries correlated well with questionnaire data. The median urinary iodine concentration (UIC) was 140 microg/L (range: 18-845 microg/L). There were significant positive associations between intake of yogurt (n = 9, p = 0.01) and saltwater fish (n = 6, p = 0.0003), and an inverse correlation between bagels (n = 5, p = 0.0006) and UIC. We found no associations between self-reported milk, iodized salt, tobacco use, or urinary cotinine and UIC.


CONCLUSIONS
The questionnaire may not have been sufficiently comprehensive. Given the importance of adequate dietary iodine intake, particularly among women of childbearing age, further studies are warranted to determine important sources of dietary iodine in the United States.
Leung
Angela M
AM
Section of Endocrinology, Diabetes, and Nutrition, Boston University Medical Center, Boston, Massachusetts, USA.
Braverman
Lewis E
LE
Pearce
Elizabeth N
EN
D000328:Adult; D000818:Animals; D001900:Boston; D003367:Cotinine / Q000652:urine; D015930:Diet Records; D002523:Edible Grain; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D008892:Milk; D017747:Seafood; D012907:Smoking; D011795:Surveys and Questionnaires; D013959:Thyroid Diseases / Q000517:prevention & control; D015014:Yogurt
D007455:Iodine; D003367:Cotinine