Race/Ethnicity and the prevalence of thyrotoxicosis in young Americans.
BACKGROUND
Race/ethnicity may be a newly recognized risk factor for Graves' disease.


OBJECTIVE
The aim of this study was to examine the prevalence of thyrotoxicosis by race/ethnicity in Americans aged 12-49 years using three National Health and Nutritional Examination Surveys (NHANES).


METHODS
Data were analyzed from 17,939 participants in NHANES III (1988-1994), NHANES 1999-2002, and NHANES 2007-2010 with available thyroid function test results. Thyrotoxicosis was defined as a serum thyrotropin (TSH) of ≤0.1 mIU/L or subjects taking methimazole or propylthiouracil, and overt thyrotoxicosis was defined as high serum thyroxine and a serum TSH of ≤0.1 mIU/L. Logistic regression was performed accounting for the complex sampling design of NHANES, and the results from all three NHANES surveys were combined using a random-effects model.


RESULTS
There were 75 study participants with point prevalent thyrotoxicosis, representing a pooled prevalence of 0.4% for Americans aged 12-49 years. Prevalent thyrotoxicosis was nearly three times more likely in non-Hispanic black subjects compared with non-Hispanic whites (OR=2.9 [CI 1.5-5.7]), while there was no difference between the prevalence of thyrotoxicosis in Mexican Americans compared to non-Hispanic whites (OR=1.2 [CI 0.6-2.4]; I2 for heterogeneity=0% for both). Among 27 patients with overt thyrotoxicosis, the odds ratio was 8.7 [CI 0.7-112.6] for non-Hispanic blacks and 4.6 [CI 0.4-59.3] for Mexican Americans compared with non-Hispanic whites.


CONCLUSIONS
The results suggest there are race/ethnicity differences in the prevalence of thyrotoxicosis. Future studies should address whether these differences are due to heritable factors, environmental exposures, or a combination of both.
1Department of Endocrinology and Diabetes, Royal Brisbane and Women's Hospital, Herston, Australia.|2Population Health Department, QIMR Berghofer Medical Research Institute, Herston, Australia.
Donald S A
DS
McLeod
3Division of Endocrinology, Diabetes, and Metabolism, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
David S
DS
Cooper
3Division of Endocrinology, Diabetes, and Metabolism, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
Paul W
PW
Ladenson
2Population Health Department, QIMR Berghofer Medical Research Institute, Herston, Australia.
David C
DC
Whiteman
2Population Health Department, QIMR Berghofer Medical Research Institute, Herston, Australia.
Susan J
SJ
Jordan
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D013956:Antithyroid Agents / Q000627:therapeutic use; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D017058:Mexican Americans / Q000706:statistics & numerical data*; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D011441:Propylthiouracil / Q000627:therapeutic use; D012307:Risk Factors; D013971:Thyrotoxicosis / Q000097:blood / Q000188:drug therapy / Q000208:ethnology*; D013972:Thyrotropin / Q000097:blood; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult
D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil; D013972:Thyrotropin