Hypothyroidism (underactive thyroid) raises the risk of type 2 diabetes, according to a new study. The findings revealed that the risk still remained even in those patients who had their hormone levels under control.
Hypothyroidism is characterized by the insufficient hormone production, which thus leads to a slower metabolism, which can contribute to weight gain. Previous studies found a link between hypothyroidism and reduced insulin sensitivity, which is a precursor to type 2 diabetes.
The study took place over the course of eight years, tracking nearly 8,500 seniors over the age of 65. Blood samples were taken from the participants to measure blood sugar as well as thyroid function. The participants were reevaluated every few years to check on type 2 diabetes.
After nearly eight years, 1,100 participants developed prediabetes and 798 developed full-on type 2 diabetes. The researchers found that low thyroid function increased the risk of type 2 diabetes by 13 percent. Furthermore, those with prediabetes and low thyroid function were at a greater risk to develop type 2 diabetes – 40 percent higher.
Study lead Dr. Layal Chaker said, “We found it surprising that even people whose thyroid function was in the low-normal range had an increased risk of diabetes. Future studies should investigate whether screening for and treatment of subclinical hypothyroidism [mildly low thyroid function] is beneficial in subjects at risk of developing diabetes.”
Dr. Minisha Sood, director of inpatient diabetes at Lenox Hill Hospital, added, “There is some evidence to show that low thyroid function can increase insulin resistance. Most endocrinologists screen for thyroid disease in patients with prediabetes and diabetes, because it is known that thyroid disease is more prevalent in these populations.”
The findings are considered preliminary until they are published in a peer-reviewed journal.