Higher free triiodothyronine concentration is associated with lower prevalence of microangiopathic complications and better metabolic control in adult euthyroid people with type 1 diabetes

Abstract

PurposeType 1 diabetes mellitus (T1DM) is a disorder of insulin deficiency but with a wide range of hormones simultaneously disturbed. The study was performed to explore relation of free triiodothyronine (FT3) with metabolic control and occurrence of microangiopathic complications.MethodsA total of 266 adult T1DM participants [56% men; 32 (interquartile range, IQR: 25–39) years and disease duration 13 (IQR: 8–19) years] in euthyroid state with negative history for hypothyroidism were included to the study. Participants were screened for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and FT3. Moreover, microangiopathic complications (retinopathy, diabetic kidney disease, peripheral and autonomic neuropathy), markers of metabolic control such as glycated hemoglobin (HbA1c) were evaluated.ResultsA total of 114 (42.9%) people had diagnosed at least one microangiopathic complication. In multivariable linear regression higher HbA1c was statistically significant independent predictor of lower FT3 (β = −0.25; p < 0.0001) after adjustment for sex, T1DM duration, HbA1c, waist-to-hip ratio (WHR) (R2 = 0.15, p < 0.0001). Higher FT3 was simultaneously a predictor of lower prevalence of microangiopathy in multivariate logistic regression analysis (odds ratio, 0.51; 95% confidence interval, 0.27–0.98; p = 0.04) after an adjustment for: age, hypertension, HbA1c, WHR and total cholesterol (TC).ConclusionsFT3 as tissue active hormone plays a clinically important role in T1DM people. The higher FT3 concentration is related to the lower prevalence of microangiopathy and better metabolic control of the disease in adult euthyroid people with T1DM.

Thyroid dysfunction and risk factors in patients with newly diagnosed type 2 diabetes: A cross-sectional study

“…The presence of low T3 syndrome was significantly associated with microalbuminuria. Recently, a study in adult euthyroid patients with T1DM showed that higher FT3 level was related to lower prevalence of microangiopathy and better metabolic control [20], which further supported our findings.…”

Thyroid dysfunction and risk factors in patients with newly diagnosed type 2 diabetes: A cross-sectional study

“…Both FT3 and FT4 levels were positively correlated with BMI in euthyroid subjects with obesity [23]. Higher FT3 concentration correlated positively with markers of obesity such as BMI in euthyroid T1DM patients [20]. However, we did not find significant difference in levels of thyroid hormones between patients with obesity (BMI ≥ 28 kg/m 2 ) and patients with relatively normal BMI values.…”

<p>Thyroid Hormone Changes in Euthyroid Patients with Diabetes</p>

“…6,7 Our study is in line with another cross-sectional study of type 2 diabetes in China 24 and an observational study of type 1 diabetes in Poland. 25 Interestingly, two longitudinal studies from Korea did not prove a statistically significant association between the incidence of diabetes and the suppressed TSH level, but the individual-level changes of TSH. 26,27 However, a cohort study from Rotterdam suggested that higher TSH levels and lower FT4 levels within the reference range of thyroid function were associated with a higher risk of diabetes, 15 while another cohort study in the Netherlands showed no association between plasma TSH levels and incident T2DM.…”