Urinary odor molecules in the Otassha Study can distinguish patients with sarcopenia: A pilot study.

Aim: To identify sarcopenia markers in urinary odor.

Methods: We performed solid-phase microextraction from the headspace and gas chromatography-mass spectrometry analysis of urinary volatile organic compounds (VOCs) in 71 healthy individuals and 68 patients diagnosed with sarcopenia according to the Asian Working Group on Sarcopenia 2019 criteria. The mass-to-charge ratios (m/z) of 10 VOCs with a significant difference in the total ion chromatogram of 220 VOCs detected in this study were compared by U-test. To calculate the predictive values for sarcopenia, binomial logistic regression analyses were conducted with sarcopenia (0, 1) as the dependent variable and the m/z values of each of the 10 VOCs and all 10 VOCs as independent variables. Receiver operating characteristic (ROC) curves for predictive values were generated to evaluate diagnostic accuracy. The correlations between the predictive value and handgrip strength, usual gait speed, and skeletal muscle mass were assessed using Pearson's r.

Results: We identified 10 VOCs (p-xylene, 1-butanol, d-limonene, nonanal, pyrrole, γ-butyrolactone, texanol isomer, octanoic acid, nonanoic acid, and diisobutyl phthalate) as candidate biomarkers in urine. The ROC curve analysis showed high diagnostic accuracy of the predictive values of the 10 VOCs for sarcopenia (area under the curve = 0.866, 95% confidence interval: 0.829-0.942; sensitivity, 80.9%; specificity, 81.7%). Additionally, the predictive values significantly correlated with handgrip strength (male: r = -0.505, P < 0.0001; female: r = -0.568, P < 0.0001).

Conclusions: This study identified 10 urinary VOCs as possible non-invasive biomarkers for sarcopenia, offering insights into its onset mechanism and potential therapeutic targets. Geriatr Gerontol Int 2025; ••: ••-••.