How would untreated Hashimoto’s thyroiditis affect blood sugar levels? Also, how might starting a regimen of thyroxine affect sugar levels and/or insulin effectiveness?

My husband was diagnosed with Hashimoto’s about three years ago, two years after his diabetes diagnosis. He has wanted to avoid taking thyroxine, but now the symptoms are really starting to show. He had blood tests to measure TSH and such, as well as an ultrasound of the thyroid. He is waiting for the results and anticipating needing to take the thyroxine.

Type 1 diabetes is frequently associated with thyroid disease causing hypothyroidism. They are both autoimmune disorders and tend to occur in the same patient. Obviously, there are different levels of thyroid hormone deficiency, ranging from subclinical hypothyroidism, where replacement is controversial, all the way up to severe hypothyroidism where replacement is life-saving. One benefit from receiving thyroid hormone replacement may be just feeling better which allows everything else to get done with a little less distress. I would not anticipate a great deal of difference in blood sugar control. Any mild weight gain from the low thyroid status might be lost with a favorable improvement in insulin sensitivity. Otherwise, I think this will be okay and is a reasonable thing to pursue.

JTL