1. There is a positive association of BMI, IR, and type 2 DM with thyroid size.2. There is a positive association of BMI, IR and DM with thyroid nodules.3. There is a likely increased risk of thyroid cancer with elevated BMI and DM in women only. More studies are needed.4. There is insufficient data relating MTC and ATC with insulin or glucose abnormalities to draw conclusions. This evidence concerns the gene INS and medullary thyroid gland carcinoma.