The Association between Dietary Patterns and Hypothyroidism in Adult Population

Abstract

Background: The thyroid gland produces hormones that are essential for various body functions. Hypothyroidism occurs when the thyroid gland cannot produce enough hormones. Even though several studies have found associations between specific micronutrients and overall thyroid function, there is still a limited amount of evidence regarding the relationship between dietary patterns and hypothyroidism among the U.S. population. Based on the current literature, it is predicted that inadequate diets have an adverse effect on thyroid function. Aim: The aim of this study was to investigate the association between dietary patterns and hypothyroidism risk among US adults. Methods: Data from 3 cycles of National Health and Nutrition Examination Surveys, 2007–2008, 2009-2010, and 2011–2012 were used (n=8,317). Subjects with serum thyroid stimulating hormone (TSH ) >4.5 mIU/L or on Levothyroxine were considered having hypothyroidism. Age, sex, race-ethnicity, body mass index (BMI), physical activity, smoking status, alcohol consumption, education, poverty income ratio (PIR) and daily energy intake, were considered as covariates. Participants <18 years, missing TSH and dietary data, hyperthyroidism, outliers in energy intake, and pregnant women were excluded. Three patterns were extracted using factor analysis; Fat-Processed Grains-Sugars-Meats (FPSM), Oils-Nuts-Potatoes-Low fat meats (ONPL), and Fruits-Whole grains-Vegetables-Dairy (FWVD) patterns. Serum TSH concentrations were measured using a two-site immuno-enzymatic access assay. Results: In the multivariate adjusted model, weighted multiple logistic regression revealed that FPSM and ONPL were inversely associated with hypothyroidism (p=0.049 and p=0.025, respectively). FWVD had no association with hypothyroidism (p=0.63). Conclusion: FPSM and ONPL patterns were associated with lower hypothyroidism risk. What constituent/s in these dietary patterns is/are responsible for this association needs further investigation.