CAUSES OF THYROID DISEASE
n underactive thyroid can affect anyone at any age. In fact it is tested on about day five of life in the heel prick test as treating it from an early age if it is present can prevent complications.
However it is more common in women than men, with 1 in 50 women being af fected, yet only 1 in 1,000 men, and is commoner with increasing age. It is generally caused by an autoimmune thyroiditis. An autoimmune disease is when the body incorrectly attacks itself, and in this case it attacks the thyroid gland. All autoimmune conditions are associated with each other, so if you have one you are more likely to have another, therefore hypothyroidism is more common in people who have type 1 diabetes or vitiligo. It also tends to run in families, so you are more likely to get it if other family members are affected.
Hypothyroidism is also associated with other conditions such as Down’s syndrome or Turner syndrome. Hypothyroidism can also develop post surgery or radiotherapy to the neck or thyroid gland (sometimes for thyroid cancer or an overactive thyroid). Iodine is required to make thyroxine, so iodine deficiency can cause an underactive thyroid – this is the commonest cause.
An overactive thyroid can also develop at any age though is commoner with increasing age. Again, it’s commoner in women than men. The condition has various causes, the most common of which is Grave’s disease, which is also an autoimmune disease where the immune system attacks the body, but this time it causes the thyroid to become overactive.
You can also get nodules on your thyroid which becomes autonomous and doesn’t respond to the normal regulating hormones which dictate how much thyroxine to make, instead they just produce too much! More rarely thyroid cancer can cause an overactive thyroid.