Prevalence of Thyroid Dysfunction in a Chinese Population with Different Glucose Intolerance Status: A Community-Based Cross-Sectional Study

Aim: Impaired glucose metabolism and thyroid dysfunction (TD) are the two most common chronic metabolic disorders. This study aimed to investigate the epidemiological characteristics of TD in different status of glucose tolerance in a community-based Chinese population and to understand the association between TD and glucose metabolism. Methods: A community-based population study of metabolic disease was conducted from June 2013 to September 2014 in Beijing, China. Residents aged 26-76 years were selected according to gender and age composition using multi-stage stratified random sampling process. All participants underwent serum thyroid function and thyroid-associated antibody tests. The status of glucose tolerance was determined using 75g-oral glucose tolerance test. Chi-square test was used to compare the differences in prevalence. Multivariate logistic regression analysis was used to determine the impact of insulin resistance (IR) on thyroid function. Results: By analyzing 3986 participants who were included in the survey, the prevalence of type 2 diabetes (T2DM) and pre-diabetes (pre-DM) was 18.59% and 26.79%, respectively. The prevalence of TD was 8.81%, with overt hyperthyroidism accounting for 0.38%; subclinical hyperthyroidism, 1.86%; overt hypothyroidism, 0.70%; and subclinical hypothyroidism, 5.87%. The prevalence of TD increased with gradually deteriorated glucose tolerance (7.63% in those with normal glucose tolerance, 9.27% in pre-DM, and 11.61% in T2DM) in both men and women. Each unit of higher HOMA-IR was associated with 7% higher likelihood of having subclinical hypothyroidism. Conclusion: The coexisting of TD with T2DM and pre-DM is high in this community based Chinese population, suggesting a close relationship between TD and glucose metabolism.