The association between serum soluble [alpha]-Klotho and thyroid profile among adults from NHANES 2007-2012

Background Thyroid hormone is the key endocrine regulator of growth, development, metabolism, and other bodily functions. [alpha]-Klotho has been involved in the aging process and acts as an endocrine factor involved in the regulation of various metabolic processes in humans. However, the relationship between [alpha]-Klotho and thyroid profile has not been uniformly recognize. Objective To determine the relationship between [alpha]-Klotho and thyroid profile in adult individuals. Methods Population data of 4614 adult individuals were obtained from the NHANES database during the period of 2007-2012. Weighted multivariable regression analysis was performed using a general linear model with serum [alpha]-Klotho as the independent variable and thyroid profile as the dependent variables, respectively. The generalized additive model was used for smoothing curve fitting and threshold effect analysis. Results [alpha]-Klotho was associated with a slightly higher FT3, TT3 and TT4 level in unadjusted and adjusted regression models. However, a higher [alpha]-Klotho level was associated with a lower TSH level. After [alpha]-Klotho was grouped as quantiles with reference (Q1), [alpha]-Klotho still showed a statistically significant positive correlation with FT3 and TT3 levels in Q2, Q3 and Q4. In addition, [alpha]-Klotho was positively corrected with TT4, but negatively associated with TSH in Q4. Conclusions Serum soluble [alpha]-Klotho was positively associated with FT3, TT3 and TT4, but negatively correlated with TSH. The significant effect of [alpha]-Klotho on thyroid profile suggests its potential as a predictive marker of thyroid functions, indicating its possible involvement in the regulation of thyroid hormone secretion. Keywords: [alpha]-Klotho, Thyroid profile, TSH, NHANES