Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.
Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
Endocrine. 2020 Oct;70(1):107-114. doi: 10.1007/s12020-020-02312-6. Epub 2020 Apr 24.
Thyroid hormones (THs) have multiple effects on lipid synthesis, mobilization, and degradation, suggesting that THs may affect the development of dyslipidemia. However, prospective studies on the association between serum THs levels and incident dyslipidemia in euthyroid subjects are limited. Therefore, we conducted a cohort study (~5-year follow-up period, median: 3.0 years) to explore whether THs can affect incident dyslipidemia in a general euthyroid population aged 18 years old and over.
Dyslipidemia is characterized by elevated total cholesterol (TC), triglyceride (TG), or low-density lipoprotein cholesterol (LDL-C), or reduced high-density lipoprotein cholesterol (HDL-C). Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were determined by chemiluminescence immunoassay. Multivariable Cox proportional hazards regression models were used to assess the association between baseline FT3, FT4, TSH, and the risk of various dyslipidemias.
During follow-up period, the incidence of elevated TC, TG, LDL-C, and reduced HDL-C was 29.3%, 20.7%, 24.8%, and 19.5%, respectively. After adjustment for multiple confounders, we found that per unit increase in FT3 concentrations were associated with decreased incidence of elevated TC and LDL-C, and the hazard ratios (95% confidence interval) were 0.87 (0.79-0.97) (P < 0.01) and 0.897 (0.808-0.995) (P = 0.04), respectively. We also found a weak positive association between TSH and incidence of reduced HDL-C (P = 0.02). However, we found no association between FT4 and incident dyslipidemia.
Our results demonstrated that low FT3 was associated with high dyslipidemia risk, especially for elevated TC and LDL-C, and that TSH had a weak positive effect on incidence of reduced HDL-C.
甲状腺激素（THs）对脂质的合成、动员和降解有多种影响，这表明 THs 可能影响血脂异常的发生。然而，关于甲状腺功能正常人群中血清 THs 水平与血脂异常事件之间的前瞻性研究有限。因此，我们进行了一项队列研究（~5 年随访期，中位数：3.0 年），以探讨甲状腺功能正常人群中 THs 是否会影响血脂异常的发生。
血脂异常的特征是总胆固醇（TC）、甘油三酯（TG）或低密度脂蛋白胆固醇（LDL-C）升高，或高密度脂蛋白胆固醇（HDL-C）降低。采用化学发光免疫分析法测定血清游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）和促甲状腺激素（TSH）。采用多变量 Cox 比例风险回归模型评估基线 FT3、FT4、TSH 与各种血脂异常风险之间的关系。
在随访期间，TC、TG、LDL-C 和 HDL-C 升高的发生率分别为 29.3%、20.7%、24.8%和 19.5%。调整多种混杂因素后，我们发现 FT3 浓度每增加一个单位，TC 和 LDL-C 升高的发生率降低，风险比（95%置信区间）分别为 0.87（0.79-0.97）（P<0.01）和 0.897（0.808-0.995）（P=0.04）。我们还发现 TSH 与 HDL-C 降低的发生率呈弱正相关（P=0.02）。然而，我们没有发现 FT4 与血脂异常事件之间的关联。
我们的结果表明，低 FT3 与血脂异常风险增加相关，尤其是 TC 和 LDL-C 升高，而 TSH 对 HDL-C 降低的发生率有微弱的正效应。
