INS and thyroiditis: They presented significantly higher levels of TG (p < 0.001), non-HDL-C (p = 0.012), AIP (p < 0.001), insulin (p = 0.007), HOMA-IR (p = 0.018), HOMA-β (p = 0.028), and TyG index (p < 0.001) and lower levels of HDL-C (p = 0.014), Ca (p = 0.011), and HOMA-ISI (p = 0.018) than those with sufficient vitamin D. For thyroid-associated variables, although within the normal ranges, FT3, FT4, and TSH levels were significantly higher in the vitamin D deficiency group than the vitamin D sufficiency group (all p < 0.001).