Higher normal TSH levels may indicate lower stroke risk in type 2 diabetes
Among adults with type 2 diabetes, those who trend toward the higher end of the normal range for thyroid-stimulating hormone may be less likely to experience a stroke, according to findings published in Diabetes Research and Clinical Practice.
Other cardiovascular events and death from CV causes were not associated with TSH level among adults with type 2 diabetes, according to researchers.
“Research into additional risk factors for CVD in patients with type 2 diabetes is important, because there is still an residual risk even in patients with good glucose control and with adequate risk factor control according to the international guidelines,” Jan Westerink, MD, PhD, an internist and specialist in the department of vascular medicine at the University Medical Centre Utrecht in the Netherlands, told Endocrine Today. “This means that there are likely still unrecognized risk factors for CVD in patients with type 2 diabetes. Thyroid function may be one such a risk factor for the risk of stroke.”
Westerink and colleagues identified instances of major adverse CV events, including myocardial infarction, stroke and vascular death, across a median of 6.4 years of follow-up from questionnaires completed by 1,265 adults with type 2 diabetes (mean age, 61 years; 27% women) with baseline TSH between 0.35 mIU/L and 5 mIU/L from the Second Manifestations of Arterial Disease (SMART) study. The researchers noted that these individuals were “representative of people with high cardiovascular risk.”
The researchers noted that for every 1 mIU/L increase in plasma TSH, there was a 46% reduction in stroke risk (HR = 0.64; 95% CI, 0.45-0.88).
“[What is] important to realize is that this study concerns TSH levels that are considered to be ‘normal.’ It raises the question whether the current reference ranges for TSH are appropriate,” Westerink said. “Furthermore, TSH may be a prognostic factor of interest in future risk prediction.”
The primary outcome of all combined major adverse CV events, as well as secondary outcomes of individual events, such as MI, vascular mortality and all-cause mortality, were not associated with TSH levels, according to the researchers.
“It is possible that, as people with type 2 diabetes already have such a high risk of cardiovascular events and mortality, the hypothesized added effect from thyroid function is unimportant,” the researchers wrote. – by Phil Neuffer
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Jan Westerink, MD, PhD, can be reached at J.Westerinkemail@example.com.
Disclosures: The authors report no relevant financial disclosures.