What causes multinodular goitre? The cause(s) of multinodular goitre are, in most cases, unknown. Over a period of time, nodules are formed due to different rates of growth in different parts of the gland, possibly combined with other external influences such as diet, drugs or genes.

What causes thyroid nodules to grow?

The majority of thyroid nodules are caused by an overgrowth of normal thyroid tissue. The cause of this overgrowth is usually unknown, but there is a strong genetic basis. In rare cases, thyroid nodules are associated with: Hashimoto's thyroiditis, an autoimmune disease that leads to hypothyroidism.

What causes goiters to grow?

What causes a goiter? Iodine deficiency is the main cause of goiters. Iodine is essential to helping your thyroid produce thyroid hormones. When you don't have enough iodine, the thyroid works extra hard to make thyroid hormone, causing the gland to grow larger.