High blood sugar
Hyperglycemia, or high blood sugar, and hypothyroidism go hand-in-hand. When Indian researchers studied hemoglobin A1c levels (HBA1c) in diabetics, they found that those who also had hypothyroidism had higher levels of the protein associated with high blood sugar. But there is a silver lining to this news: When the researchers treated the diabetic patients with thyroid hormone replacement, they found that their HBA1c levels dropped significantly.