Association Between Methylmalonic Acid and Alpha-Klotho in American Adults:a Cross-Sectional Study

Methylmalonic acid is a surrogate biomarker of mitochondrial dysfunction and oxidative stress. Serum soluble α-Klotho, as a key anti-aging factor, is regarded as one of the biomarkers of aging .The correlation between Methylmalonic Acid (MMA) and Alpha-Klotho (α-Klotho) remains uncertain .This study aims to explore the relationship between MMA and Alpha-Klothoα-Klotho in American adults .Based on the availability of complete biochemical assays for methylmalonic acid (MMA) and α-Klotho, we restricted our analyses to the 2011–2014 cycles of the National Health and Nutrition Examination Survey (NHANES), which included 5,216 eligible participants with comprehensive laboratory data .Due to the limited amount of data, there may be a selection bias.In this study , MMA serves as the independent variable while α-Klotho functions as the dependent variable .MMA is a categorical variable , while α-Klotho is a categorical variable .The covariates examined include sociodemographic factors , lifestyle choices , and various systemic diseases . Logistic regression was used to assess the associations between covariates and different independent groups .To explore the relationship between serum MMA levels and α-Klotho , we employed three models : Model 1 adjusted for age , gender , race/ethnicity , education , Marital status ,Poverty Income Ratio (PIR) ,smoking, Body Mass Index (BMI)and Physical activity (PA) .Model 2 included all variables from Model 1 plus Cardiovascular diseases (CVD),Hypertension, Diabetes Mellitus (DM) .Considering the collinearity problem ,Model 3 adjusted for Marital status ,PIR ,Educations ,Smoke ,PA ,CVD ,Hypertension , DM ,Glycated Hemoglobin A1c (HbA1c) , High-Density Lipoprotein (HDL) ,Vitamin B12 (VitB12) , Glomerular Filtration Rate (eGFR).