Increased waist circumference is independently associated with hypothyroidism in Mexican Americans: Replicative evidence from two large, population-based studies

Manju Mamtani, Hemant Kulkarni, Thomas D. Dyer, Laura Almasy, Michael C. Mahaney, Ravindranath Duggirala, Anthony G. Comuzzie, Paul B. Samollow, John Blangero, Joanne E. Curran

    Research output: Contribution to journalArticle

    8 Scopus citations

    Abstract

    Background: Mexican Americans are at an increased risk of both thyroid dysfunction and metabolic syndrome (MS). Thus it is conceivable that some components of the MS may be associated with the risk of thyroid dysfunction in these individuals. Our objective was to investigate and replicate the potential association of MS traits with thyroid dysfunction in Mexican Americans.Methods: We conducted association testing for 18 MS traits in two large studies on Mexican Americans - the San Antonio Family Heart Study (SAFHS) and the National Health and Nutrition Examination Survey (NHANES) 2007-10. A total of 907 participants from 42 families in SAFHS and 1633 unrelated participants from NHANES 2007-10 were included in this study. The outcome measures were prevalence of clinical and subclinical hypothyroidism and thyroid function index (TFI) - a measure of thyroid function. For the SAFHS, we used polygenic regression analyses with multiple covariates to test associations in setting of family studies. For the NHANES 2007-10, we corrected for the survey design variables as needed for association analyses in survey data. In both datasets, we corrected for age, sex and their linear and quadratic interactions.Results: TFI was an accurate indicator of clinical thyroid status (area under the receiver-operating-characteristic curve to detect clinical hypothyroidism, 0.98) in both SAFHS and NHANES 2007-10. Of the 18 MS traits, waist circumference (WC) showed the most consistent association with TFI in both studies independently of age, sex and body mass index (BMI). In the SAFHS and NHANES 2007-10 datasets, each standard deviation increase in WC was associated with 0.13 (p < 0.001) and 0.11 (p < 0.001) unit increase in the TFI, respectively. In a series of polygenic and linear regression models, central obesity (defined as WC ≥ 102 cm in men and ≥88 cm in women) was associated with clinical and subclinical hypothyroidism independent of age, sex, BMI and type 2 diabetes in both datasets. Estimated prevalence of hypothyroidism was consistently high in those with central obesity, especially below 45y of age.Conclusions: WC independently associates with increased risk of thyroid dysfunction. Use of WC to identify Mexican American subjects at high risk of thyroid dysfunction should be investigated in future studies.

    Original languageEnglish (US)
    Article number46
    JournalBMC Endocrine Disorders
    Volume14
    DOIs
    StatePublished - Jun 10 2014

    Keywords

    • Central obesity
    • Mexican Americans
    • Thyroid dysfunction
    • Waist circumference

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism

    Fingerprint Dive into the research topics of 'Increased waist circumference is independently associated with hypothyroidism in Mexican Americans: Replicative evidence from two large, population-based studies'. Together they form a unique fingerprint.

  • Cite this