Linear regression analysis showed that higher 25(OH)D levels were associated with lower TSH levels independent of age, serum thyroid hormone levels, thyroid volume, the presence of thyroid nodule(s), and smoking status in males with negative serum TPOAb, TgAb, and TPOAb and/or TgAb titres (P = 0.004, 0.004, and 0.002, resp.; Table 5), but not in females or subjects positive for serum thyroid autoantibodies (data not shown). Here, TG is linked to thyroid gland disorder.