Association of Serum Asymmetric Dimethylarginine With Muscle Strength and Gait Speed: A Cross-Sectional Study of the HEIJO-KYO Cohort.

Muscle strength and gait speed are related with functional limitations and disabilities and also predict cardiovascular and all-cause mortality. Nitric oxide (NO) plays an important role in regulating physiological process in skeletal muscles; however, the association between serum asymmetric dimethylarginine (ADMA) level, an endogenous competitive inhibitor of NO synthesis, and physical performance has not yet been studied. We investigated the associations of serum ADMA level with muscle strength and usual gait speed in a cross-sectional study of 550 elderly individuals (mean age, 71.2 ± 6.6 years). Mean ADMA level was 0.45 ± 0.06 µmol/L; mean grip and quadriceps strengths were 27.7 ± 8.4 kg and 165.1 ± 81.6 Nm, respectively; and mean gait speed was 1.37 ± 0.30 m/s. In multivariate linear regression analysis adjusted for potential confounding factors (age, gender, body weight, smoking and drinking status, household income, hypertension, diabetes, renal function, and physical activity), higher serum ADMA level was significantly associated with lower grip and quadriceps strengths and slower gait speed (grip strength: β, -1.257; 95% confidence interval [CI], -1.990 to -0.525; p = 0.001; quadriceps strength: β, -11.730; 95% CI, -20.924 to -2.536; p = 0.012; gait speed: β, -0.065; 95% CI, -0.108 to -0.022; p = 0.003). Our findings indicate the significant association between serum ADMA level and physical performance among elderly individuals, which was independent of the important potential confounders.