Type 2 Diabetes Risks Increase With Hypothyroidism, Even With Low TSH

HealthDay News — Hypothyroidism may increase risk for type 2 diabetes, even if thyroid hormone levels are kept within normal range, according to findings presented at the annual meeting of the The Endocrine Society, held from April 1 to 4 in Boston.

Layal Chaker, MD, of the Erasmus Medical Center in Rotterdam, Netherlands, and colleagues tracked 8,452 participants averaging 65 years of age. All of the participants had thyroid function measurement and longitudinal assessment of prediabetes and diabetes. They were reevaluated every few years to check for the onset of type 2 diabetes. The participants’ medical records were also reviewed.

Over a mean follow-up period of 7.9 years, 1,100 of the participants developed prediabetes and 798 developed diabetes. The team found that higher thyroid-stimulating hormone levels were associated with an increased diabetes risk (hazard ratio, 1.13), even within the reference range of thyroid function (hazard ratio, 1.24). Higher free thyroxine levels were associated with a reduced diabetes risk. Risk of progression from prediabetes to diabetes was 40% higher when comparing lowest to highest tertile within the normal range of thyroid function (P=0.002).

“These findings suggest we should consider screening people with prediabetes for low thyroid function. We found it surprising that even people whose thyroid function was in the low-normal range had an increased risk of diabetes,” Chaker said in a news release from The Endocrine Society. “Future studies should investigate whether screening for and treatment of subclinical hypothyroidism is beneficial in subjects at risk of developing diabetes.”

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