The association between insulin resistance and vascularization of thyroid nodules

Insulin resistance (IR) is an important factor for the growth and progression of thyroid nodules, which might be associated with the distribution, construction, and density of nodular vascularization.

The objective of the study was to explore the association between IR and the vascularization of thyroid nodules.

A cross-sectional, population-based study was conducted in Nanjing, China, from June to November 2011.

Among 10 050 participants aged 40-79 years, 2886 thyroid nodule cases were detected and 2532 cases met eligibility criteria for enrollment in the study.

Power Doppler was performed to measure the flow patterns, resistive index (RI), and vascular index (VI) of thyroid nodular vascularization. Fasting insulin, fasting glucose, 2-hour oral glucose tolerance test, glycosylated hemoglobin (HbA1c), homeostasis model assessment of IR (HOMA-IR), and body mass index were also tested.

HOMA-IR (R = 0.35, P < .001) and HbA1c (R = 0.19, P < .001) were positively correlated with thyroid nodular flow patterns, and the positive correlations were more significant in participants with large nodules (volume ≥ 0.2 mL). Additionally, in participants with large nodules, HOMA-IR and HbA1c were positively correlated with RI (HOMA-IR: β = .42, SE = .03, R = 0.43, P < .001; HbA1c: β = .22, SE = .04, R = 0.23, P < .001) and VI (HOMA-IR: β = .49, SE = 0.05, R = 0.53, P < .001; HbA1c: β = .34, SE = 0.11, R = 0.37, P < .001).

IR and hyperglycemia were positively correlated with the flow patterns, RI, and VI of thyroid nodules, especially in large nodules. The findings suggest a pivotal role of IR in the distribution, construction, and density of thyroid nodular vascularization, which might contribute to the growth and the progression of thyroid nodules.