Supplementary Material for: Association of Thyrotropin Concentration with Chronic Kidney Disease in a Japanese General Population Cohort

<b><i>Background:</i></b> Previous studies have indicated an association between hypothyroidism and kidney dysfunction; however, few studies have investigated whether thyroid dysfunction is a risk factor for chronic kidney disease (CKD) development. And their result is not consistent. <b><i>Objectives:</i></b> We evaluated the association of thyroid dysfunction with CKD prevalence and development by a multivariate logistic regression analysis. <b><i>Method:</i></b> In cross-sectional and longitudinal studies, 16,390 subjects and 7,609 subjects, respectively, who underwent annual health check-ups were analyzed. We categorized the subjects into the following 4 groups based on their serum thyrotropin (TSH) ­concentrations: below-normal (TSH &lt; 0.54 mU/L), lower-normal ­(0.54–2.40 mU/L), higher-normal (2.41–4.26 mU/L) and above-normal (&gt; 4.26 mU/L). Subjects with eGFR &lt;60 mL/min/1.73 m² were determined to have CKD. <b><i>Results:</i></b> The cross-sectional study revealed a positive correlation between TSH concentration and CKD ­prevalence. Compared with the lower-normal TSH group, the ORs and 95% CIs of CKD prevalence were 0.61 (0.45–0.82, <i>p</i> = 0.001) for the below-normal group, 1.49 (1.33–1.67, <i>p</i> &lt; 0.001) for the higher-normal group, and 1.90 (1.57–2.30, <i>p</i> &lt; 0.001) for the above-normal group. The longitudinal study revealed that the risk of CKD development within 3 years was significantly higher in the above-normal TSH group than in the lower-normal TSH group (OR 1.58, 95% CI 1.02–2.45, <i>p</i> = 0.04). <b><i>Conclusions:</i></b> Our data indicate that higher TSH concentrations are positively correlated with CKD prevalence and that a high TSH concentration is a risk factor for CKD development.

**<i>研究背景：</i>** 既往研究已证实甲状腺功能减退（hypothyroidism）与肾功能异常存在关联，但鲜有研究探讨甲状腺功能异常是否为慢性肾脏病（chronic kidney disease, CKD）发生的危险因素，且现有研究结论并不一致。**<i>研究目的：</i>** 本研究通过多因素logistic回归分析，评估甲状腺功能异常与慢性肾脏病患病率及发生风险的关联。**<i>研究方法：</i>** 本研究分为横断面研究与纵向研究两部分，分别纳入16390名、7609名接受年度健康体检的受试者进行分析。根据血清促甲状腺激素（thyrotropin, TSH）浓度将受试者分为4组：低于正常范围（TSH < 0.54 mU/L）、正常低值范围（0.54~2.40 mU/L）、正常高值范围（2.41~4.26 mU/L）以及高于正常范围（>4.26 mU/L）。以估算肾小球滤过率（estimated glomerular filtration rate, eGFR）<60 mL/min/1.73m²作为慢性肾脏病的判定标准。**<i>研究结果：</i>** 横断面研究结果显示，血清TSH浓度与慢性肾脏病患病率呈正相关。与正常低值TSH组相比，低于正常范围组的慢性肾脏病患病率比值比（OR）及95%置信区间（CI）为0.61（0.45~0.82，*p*=0.001），正常高值范围组为1.49（1.33~1.67，*p*<0.001），高于正常范围组为1.90（1.57~2.30，*p*<0.001）。纵向研究结果显示，随访3年内，高于正常TSH范围组的慢性肾脏病发生风险显著高于正常低值TSH组（OR=1.58，95%CI：1.02~2.45，*p*=0.04）。**<i>研究结论：</i>** 本研究数据表明，血清TSH浓度升高与慢性肾脏病患病率呈正相关，且高TSH浓度是慢性肾脏病发生的危险因素。