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

Background: 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. Objectives: We evaluated the association of thyroid dysfunction with CKD prevalence and development by a multivariate logistic regression analysis. Method: 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 < 0.54 mU/L), lower-normal ­(0.54–2.40 mU/L), higher-normal (2.41–4.26 mU/L) and above-normal (> 4.26 mU/L). Subjects with eGFR <60 mL/min/1.73 m² were determined to have CKD. Results: 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, p = 0.001) for the below-normal group, 1.49 (1.33–1.67, p < 0.001) for the higher-normal group, and 1.90 (1.57–2.30, p < 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, p = 0.04). Conclusions: 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.