Plasma S-Klotho level affects the risk of hyperuricemia in the middle-aged and elderly people

Background: Soluble Klotho (S-Klotho) is an anti-aging protein mainly secreted by the kidneys. Hyperuricemia is prevalent among middle-aged and elderly individuals, which affects the development of various chronic diseases. However, there are relatively few studies investigating the association between plasma S-Klotho levels and hyperuricemia in middle-aged and elderly individuals. This study sought to clarify the relationship between S-Klotho and the risk of hyperuricemia in middle-aged and elderly people. Methods: During 2007–2016, a total of 50,588 people participated in the National Health and Nutrition Examination Survey. Finally, 12,441 middle-aged and elderly people (aged 40–79) completed the soluble Klotho tests and had obtained complete data. S-Klotho was detected by ELISA kit, and the relationship between S-Klotho and hyperuricemia was assessed by multiple logistic regression. Hyperuricemia is defined as serum uric acid levels higher than or equal to 420 mmol/l in men and 360 mmol/l in women. Results: In the middle-aged and elderly, plasma S-Klotho levels were negatively correlated with hyperuricemia, and there was a saturation effect. The inflection point of S-Klotho was 927.8 pg/ml (logarithmic likelihood ratio test = 0.002). When plasma S-Klotho < 927.8 pg/ml, the prevalence of hyperuricemia in middle-aged and elderly individuals with higher levels of S-Klotho decreased by 25.6% compared with those with low levels of S-Klotho [Q4 vs Q1, OR: 0.744, 95%CI: (0.634, 0.874), P< 0.001]; In different age groups, S-Klotho had a significantly greater effect on hyperuricemia in middle-aged people [age: 40–65 years, Q4 vs Q1, OR (95%CI): 0.69 (0.58, 0.82), P< 0.001; Age > 65 years: Q4 vs Q1, OR (95%CI): 0.72 (0.56, 0.92), P= 0.008)].When the level of S-Klotho was higher, the risk of hyperuricemia in men was lower than that in women [male: Q4 vs Q1, OR (95%CI): 0.67 (0.56, 0.81), P< 0.001; female: Q4 vs Q1 (95%CI):0.72 (0.58, 0.88),P< 0.001]. Conclusions: In middle-aged and elderly individuals, plasma S-Klotho levels were inversely correlated with hyperuricemia, with a saturation effect. Given the limitations of the research results, the underlying mechanism between S-Klotho and hyperuricemia should be further explored.