Subclinical hypothyroidism is associated with albuminuria in Japanese nondiabetic subjects

Purpose: Thyroid dysfunction is a risk factor of cardiovascular disease (CVD), and albuminuria is a predictor of CVD. For preventing the CVD, it is essential to clarify from which stage of thyroid dysfunction the risk of CVD starts developing. We thus investigated the association between subclinical thyroid dysfunction and albuminuria, focusing on a nondiabetic general population. Methods: We analyzed the data of 17,221 nondiabetic subjects who underwent annual health checkups by multivariate logistic regression analyses. Results: Compared with the subjects with euthyroidism, those with subclinical hypothyroidism presented a higher prevalence of albuminuria. By a multivariate logistic regression analysis, subclinical hypothyroidism showed a significant and independent association with the high prevalence of albuminuria compared with euthyroidism (OR 1.64, 95% CI 1.21–2.21, p = 0.001). In accord with this result, the analysis in which the lowest quartile of thyroid stimulating hormone (TSH) concentration (<0.96 µIU/mL) was used as a reference revealed that the highest quartile (>2.07 µIU/mL) had a significant and independent association with the prevalence of albuminuria (OR 1.23, 95% CI 1.01–1.51, p = 0.04). One microliter unit per milliliter increase of the serum concentration of TSH also had a significant and independent association with the prevalence of albuminuria (OR 1.07, 95% CI 1.02–1.12, p = 0.006). The association between subclinical hyperthyroidism and the prevalence of albuminuria was not significant. Conclusion: Our data indicated that subclinical hypothyroidism was significantly and independently associated with the high prevalence of albuminuria.