Abstract
PURPOSE: We investigated the association of central obesity and glucose metabolism with thyroid nodule (TN) risk and explored whether diabetes/central obesity altered TN risk. METHODS: Data were collected in the Risk Evaluation of cAncers in Chinese diabeTic Individuals: a lONgitudinal study, which involved cross-sectional (May-August 2011) and longitudinal cohorts (July-October 2014; 3.2-year follow-up). In all, 8995 subjects were enrolled in the baseline survey; the 5655 subjects evaluated during the 3.2-year follow-up were included in this study. All subjects underwent body measurements, laboratory tests, and thyroid ultrasonography. RESULTS: Among 5655 participants, 420 had TNs. Participants with central obesity or abnormal glucose metabolism had significantly higher TN risk than participants without central obesity (OR: 1.233; 95% CI: 1.009-1.507) or abnormal glucose metabolism (OR: 1.257; 95% CI: 1.025-1.541). After adjustments for age and sex, this significance was retained for central obesity. Among participants with central obesity, prediabetes (OR: 1.483, 95% CI: 1.016-2.163) and diabetes (OR: 1.622, 95% CI: 1.078-2.407) were associated with TNs, when compared to the euglycemic subgroup (P trend = 0.040). No similar result was observed among participants without central obesity. During follow-up, the incidence rate ratio (IRR) for TNs was 1.026 (95% CI: 1.006-1.050) among those with new-onset central obesity and 1.025 (95% CI: 1.006-1.049) among those with chronic central obesity, as compared with those without central obesity. No significant associations were found among groups based on dynamic changes in glucose metabolism. Only in the chronic central obesity subgroup, new-onset prediabetes (IRR: 1.092, 95% CI: 1.020-1.169) and diabetes (IRR: 1.103, 95% CI: 1.031-1.189) significantly increased TN risk, as compared with euglycemia. CONCLUSION: TNs are associated with central obesity and abnormal glucose metabolism. Chronic/new-onset central obesity increased TN risk. New-onset prediabetes/diabetes amplified TN risk among people with chronic central obesity.