Association Between Thyroid Dysfunction and Hyperglycemia is More Significant in Females Younger Than 65 years old

Abstract Background The significant association between different levels of thyroid dysfunction and hyperglycemia has been well-established. The purpose of our research is to provide new relevant evidence while verifying the preexisting views. Methods This is a cross-sectional analysis based on 31 provinces in mainland China. We excluded subjects with a personal history of thyroid diseases or diabetes. The diagnostic criteria of different types of hyperglycemia referred to the 2018 American Diabetes Association guidelines. We explored the trend of hyperglycemia prevalence with different levels of thyroid function in the general population (N = 56,700) and analyzed the potential association between them. In addition, we explored the relationship in subgroups with different demographics and anthropometrics. Results In the overall population, overt hyperthyroidism could be regarded as a significant risk factor for impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and prediabetes. Additionally, both overt hypothyroidism and severe subclinical hypothyroidism (thyrotropin > 7.04 mU/L) could be regarded as a significant risk factor for prediabetes and diabetes. The prevalence of diabetes significantly increased, and IGT showed a significant U-shaped distribution with thyrotropin. But we did not find the distribution of IFG and prediabetes prevalence with the increase of serum thyrotropin. Further subgroup analysis revealed that the abovementioned associations also had specific distribution rules in some particular population. Conclusions Thyroid dysfunction and hyperglycemia are significantly related. For particular subgroups with thyroid dysfunction, we should pay more attention to the association between the hyperglycemia and thyroid diseases.