BOSTON — Even mild hypothyroidism may increase the risk for development of type 2 diabetes, according to study results presented here.
“Low and low-normal thyroid function are associated with an increased risk of developing type 2 diabetes and progression from prediabetes to type 2 diabetes. This is even the case within the normal range of thyroid function,” Layal Chaker, MD, of Erasmus University Medical Center, Rotterdam, Netherlands, told Endocrine Today.
“The risk of developing diabetes for people with prediabetes increases from 19% to almost 35% when going from high-normal to low-normal thyroid function,” she said.
In a population-based prospective cohort study, Chaker and colleagues evaluated data on thyroid function and blood glucose levels from 8,452 adults aged at least 45 years (mean age 65 years) enrolled in the Rotterdam Study. Mean follow-up was 7.9 years.
During the study, 1,100 participants developed prediabetes and 798 developed diabetes. After adjusting for age, sex, HDL cholesterol, blood pressure and glucose at baseline, among other variables, researchers found that higher thyroid-stimulating hormone levels were associated with higher diabetes risk (HR = 1.13; 95% CI, 1.08-1.18, per logTSH), and higher free thyroxine levels with lower risk (HR = 0.96, CI, 0.93-0.99, per pmol/L). These associations were present even within the reference range of thyroid function (TSH, HR = 1.24; 95% CI, 1.06-1.45; free T4, HR = 0.96; 95% CI, 0.93-0.99, per pmol/L). Comparing the lowest with the highest tertile within the normal range of thyroid function, researchers found a 1.4-times higher risk for progression from
prediabetes to diabetes (P = .002).
“Our results could indicate a role for thyroid hormone in the pathophysiology of diabetes type 2 development,” Chaker said. “We yet need to fully understand the relation and exact thyroid hormone action leading to the increased risk of diabetes. However, our results have potential implications in screening and the prevention of diabetes type 2, mainly in those with prediabetes.” – by Jill Rollet
Chaker L, et al. OR33-2. Presented at: The Endocrine Society Annual Meeting; April 1-4, 2016; Boston.
Disclosure: Chaker reports no relevant financial disclosures.