If you are hypothyroid, you may notice that if you stay on a steady dose of thyroid hormone replacement medication during colder months, you may feel somewhat more hypothyroid. Some physicians routinely recommend that their hypothyroid patients raise their medication dosage slightly during colder months, and drop back down to a lower dose during warmer temperatures. If you notice hypothyroidism symptoms becoming more troublesome during colder weather, you may want to ask your doctor about a seasonal dosage adjustment.
Symptoms are not the only risk of colder temperatures. Now, research shows that living in a colder climate is also a risk factor for developing thyroid cancer.
Researchers looked at correlations between average temperature by state, and the rates of thyroid cancers. (They adjusted for exposure to radiation, a key risk factor for thyroid cancer.)
What they found was that living in colder areas significantly increases the risk of developing thyroid cancer. For example, living in Alaska actually doubled the risk of thyroid cancer, compared to a warmer state such as Texas.
Maybe the snowbirds who head to a warmer climate for the winter have the right idea! At minimum, it's clearly better for their thyroid health!
Source: Lehrer Steven and Rosenzweig Kenneth E.. Clinical Thyroidology. October 2014, 26(10): 273-276. doi:10.1089/ct.2014;26.273-276. Volume: 26 Issue 10: October 15, 2014 Online