Endocrinology and Metabolic Diseases Unit, Department of Medical, Surgical, Neurological, Metabolic, Geriatric Sciences and Aging, University of Campania "L. Vanvitelli", Piazza L. Miraglia 2, 80138, Naples, Italy.
Diabetes Unit, Department of Medical, Surgical, Neurological, Metabolic Sciences and Aging, University of Campania "L. Vanvitelli", Naples, Italy.
J Endocrinol Invest. 2018 Apr;41(4):389-393. doi: 10.1007/s40618-017-0752-5. Epub 2017 Aug 30.
A relationship between thyroid dysfunction and diabetes mellitus has been described by several authors but the role of glycemic variability is still unclear. We planned the present study to evaluate the influence of glycemic variability on thyroid hormones and TSH concentrations in patients with type 1 diabetes mellitus (T1DM).
Seventy-seven young patients with T1DM were enrolled and evaluated for basal glucose concentrations, HbA1c, thyroid hormones and TSH concentrations. Glucose variability was investigated by considering the standard deviation of blood glucose readings and by calculating the mean amplitude of glycemic excursions and continuous overlapping net glycemic action (CONGA). The low (LBGI) and high (HBGI) blood glucose indices were also calculated. The correlations between TSH, thyroid hormones, glycemia and HbA1c were studied in patients and in controls, whereas those between TSH, thyroid hormones and indices of glucose variability only in patients.
No correlations were observed in T1DM patients between free thyroid hormones and glycemic values, HbA1c and indices of glucose variability, while an inverse correlation was observed between TSH levels and glycemic values (r = -0.27; p = 0.01), CONGA index (r = -0.35; p = 0.001) and HBGI (r = -0.28; p = 0.01) but not with HbA1c (r = -0.1; p = 0.47).
Our results suggest a direct action of glycemic excursions on TSH secretion, regardless of variations of thyroid hormone concentrations. Thus, the evaluation of thyroid function through the assay of TSH concentrations in these patients should be made, if possible, by multiple samples on patients in euglycemic state to avoid underestimation or overestimation of thyroid dysfunction due to a wrong diagnosis of euthyroidism or dysthyroidism with consequent inappropriate choice of therapeutic options.
一些作者描述了甲状腺功能障碍与糖尿病之间的关系，但血糖变异性的作用仍不清楚。我们计划本研究评估血糖变异性对 1 型糖尿病（T1DM）患者甲状腺激素和 TSH 浓度的影响。
纳入了 77 名年轻的 T1DM 患者，评估了他们的基础血糖浓度、HbA1c、甲状腺激素和 TSH 浓度。通过考虑血糖读数的标准差和计算血糖波动的平均幅度以及连续重叠净血糖作用（CONGA）来研究血糖变异性。还计算了低（LBGI）和高（HBGI）血糖指数。在患者和对照组中研究了 TSH、甲状腺激素、血糖和 HbA1c 之间的相关性，而仅在患者中研究了 TSH、甲状腺激素和血糖变异性指标之间的相关性。
在 T1DM 患者中，游离甲状腺激素与血糖值、HbA1c 和血糖变异性指数之间没有相关性，而 TSH 水平与血糖值（r=-0.27；p=0.01）、CONGA 指数（r=-0.35；p=0.001）和 HBGI（r=-0.28；p=0.01）呈负相关，但与 HbA1c 无关（r=-0.1；p=0.47）。
我们的结果表明，血糖波动对 TSH 分泌有直接作用，而与甲状腺激素浓度的变化无关。因此，如果可能的话，通过对处于血糖正常状态的患者进行多次样本检测来评估这些患者的甲状腺功能，以避免由于错误诊断为甲状腺功能正常或甲状腺功能亢进或减退而导致的甲状腺功能障碍的低估或高估，从而导致治疗选择不当。
