Smoking and Other Lifestyle Factors and the Risk of Graves’ Hyperthyroidism

Abstract

Graves’ disease is an autoimmune disorder characterized by hyperthyroidism, goiter, ophthalmopathy, and dermopathy. Among women, the incidence of hyperthyroidism, the most common manifestation of the disease, has been estimated to be 0.1 to 1 per 1000 women per year.^1-3 Given this frequency, it is surprising how little is known about risk factors for the disorder. Based on family and twin studies, genetic factors are important.^4-7 Postulated environmental and lifestyle risk factors include cigarette smoking,^8-10 stress and adverse life events,^4,10,11 and high dietary iodine intake.¹² Alcohol consumption may be protective.^4,10 The evidence linking these factors to Graves’ hyperthyroidism is based on small case-control studies, which are prone to recall bias. To our knowledge, no large prospective cohort studies of Graves’ hyperthyroidism have been conducted.