Association between serum Klotho and the prevalence of osteoarthritis: A cross-sectional study from NHANES 2007-2016

Osteoarthritis (OA) is a degenerative joint disease prevalent in the elderly. Currently, the relationship between the senescence inhibitor Klotho and OA remains unclear. This study investigated the relationship between serum soluble Klotho (S-Klotho) and OA.

This cross-sectional study was based on the 2007-2016 National Health and Nutrition Examination Survey (NHANES). Three multifactorial logistic regression models were constructed to assess the association between serum Klotho and OA. Restricted cubic spline (RCS) curves were further used to assess whether there was a nonlinear relationship between serum Klotho and OA. Finally, stratified analyses and interaction tests were used to evaluate the association's stability. To further investigate the relationship between serum Klotho and OA, we recruited 107 patients for analysis at the First Affiliated Hospital of Guangxi Medical University.

The final 8,918 participants included in this study comprised 50.55% females and 49.45% males, with 18.10% of participants suffering from OA and a mean S-Klotho level of 846.41 (5.61) pg/ml. All three logistic regression models observed a negative association between continuous S-Klotho and OA risk. When S-Klotho was categorized into tertiles, the fully adjusted model showed that participants in the third tertile had a 17% lower risk of OA than those in the first tertile (OR = 0.83, 95% CI: 0.70, 0.99, P = 0.035). The RCS curves showed a linear negative association between S-Klotho and the incidence of OA (P for overall = 0.025; P for non-linearity = 0.667). Further subgroup analyses and interaction tests suggested that the negative association between S-Klotho and OA remained stable in different conditions. Research conducted in China has shown that the negative correlation between serum Klotho levels and the prevalence of OA remains evident among Chinese individuals (OR: 0.77, 95% CI: 0.66, 0.90, P<0.001).

Our study suggests that elevated levels of the senescence inhibitor S-Klotho may be a potential protective factor for OA, which may provide new insights into the diagnosis and treatment of OA.