Prevalence of hyperthyroidism according to type of vegetarian diet

Public Health Nutr. 2015 Jun;18(8):1482-7. doi: 10.1017/S1368980014002183. Epub 2014 Sep 29.


Objective: Vegetarian diets may be associated with low prevalence of autoimmune disease, as observed in rural sub-Saharan Africans. Graves' disease, an autoimmune disorder, is the most common cause of hyperthyroidism. We studied prevalence of hyperthyroidism according to dietary pattern in a population with a high proportion of vegetarians.

Design: Cross-sectional prevalence study. The association between diet and prevalence of hyperthyroidism was examined using multivariate logistic regression analyses controlling for sociodemographic characteristics and salt use.

Setting: The Adventist Health Study-2 conducted in the USA and Canada.

Subjects: Church members (n 65 981) provided demographic, dietary, lifestyle and medical history data by questionnaire.

Results: The prevalence of self-reported hyperthyroidism was 0·9 %. Male gender (OR=0·32; 95 % CI 0·26, 0·41) and moderate or high income (OR=0·67; 95 % CI 0·52, 0·88 and OR=0·73; 95 % CI 0·58, 0·91, respectively) protected against hyperthyroidism, while obesity and prevalent CVD were associated with increased risk (OR=1·25; 95 % CI 1·02, 1·54 and OR=1·92; 95 % CI 1·53, 2·42, respectively). Vegan, lacto-ovo and pesco vegetarian diets were associated with lower risk compared with omnivorous diets (OR=0·49; 95 % CI 0·33, OR=0·72, 0·65; 95 % CI 0·53, 0·81 and OR=0·74; 95 % CI 0·56, 1·00, respectively).

Conclusions: Exclusion of all animal foods was associated with half the prevalence of hyperthyroidism compared with omnivorous diets. Lacto-ovo and pesco vegetarian diets were associated with intermediate protection. Further study of potential mechanisms is warranted.

Keywords: Thyroid.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Africa South of the Sahara / epidemiology
  • Aged
  • Body Mass Index
  • Cardiovascular Diseases / epidemiology*
  • Cross-Sectional Studies
  • Diet, Vegetarian*
  • Female
  • Humans
  • Hyperthyroidism / epidemiology*
  • Life Style
  • Logistic Models
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Obesity / epidemiology*
  • Prevalence
  • Risk Factors
  • Surveys and Questionnaires