Suchergebnisse

Abstract

Background
Lower urinary tract symptoms (LUTS) and mobility limitations are bidirectionally associated among older adults, but the role of skeletal muscle remains unknown. We evaluated cross-sectional associations of muscle health and physical performance with LUTS.


Methods
We used data from 377 women and 264 men aged >70 years in the Study of Muscle, Mobility and Aging (SOMMA). LUTS and urinary bother were assessed using the LURN Symptom Index-10 (SI-10; higher = worse symptoms). Muscle mass and volume were assessed using D3-creatine dilution (D3Cr) and magnetic resonance imaging. Grip strength and peak leg power assessed upper/lower extremity physical performance. 400-m walk, Short Physical Performance Battery (SPPB), and Four Square Step Test (FSST) assessed global physical performance. Mobility Assessment Tool-short form (MAT-sf) assessed self-reported mobility. We calculated Spearman correlation coefficients adjusted for age, body mass index, multimorbidity, and polypharmacy, chi-square tests, and Fisher's Z-test to compare correlations.


Results
Among women, LURN SI-10 total scores were inversely correlated with FSST (rs = 0.11, p = .045), grip strength (rs = −0.15, p = .006), and MAT-sf (rs = −0.18, p = .001), but not other muscle and physical performance measures in multivariable models. LURN SI-10 was not associated with any of these measures among men. Forty-four percent of women in the lowest tertile of 400-m walk speed versus 24% in the highest tertile reported they were at least "somewhat bothered" by urinary symptoms (p < .001), whereas differences among men were not significant.


Conclusions
Balance and grip strength were associated with LUTS severity in older women but not men. Associations with other muscle and physical performance measures varied by LUTS subtype but remained strongest among women.

Abstract
Tryptophan (TRP) metabolites along the kynurenine (KYN) pathway (KP) have been found to influence muscle. Proinflammatory cytokines are known to stimulate the degradation of TRP down the KP. Given that both inflammation and KP metabolites have been connected with loss of muscle, we assessed the potential mediating role of KP metabolites on inflammation and muscle mass in older men. Five hundred and five men (85.0 ± 4.2 years) from the Osteoporotic Fractures in Men cohort study with measured D3-creatine dilution (D3Cr) muscle mass, KP metabolites, and inflammation markers (C-reactive protein [CRP], alpha-1-acid glycoprotein [AGP] and a subsample [n = 305] with interleukin [IL-6, IL-1β, IL-17A] and tumor necrosis factor-α [TNF-α]) were included in the analysis. KP metabolites and inflammatory markers were measured using liquid chromatography-tandem mass spectrometry and immunoassays, respectively. 23%–92% of the inverse relationship between inflammatory markers and D3Cr muscle mass was mediated by KP metabolites (indirect effect p < .05). 3-hydroxyanthranilic acid (3-HAA), quinolinic acid (QA), TRP, xanthurenic acid (XA), KYN/TRP, 3-hydroxykynurenine (3-HK)/3-HAA, QA/3-HAA, and nicotinamide (NAM)/QA mediated the AGP relationship. 3-HAA, QA, KYN/TRP, 3-HK/XA, HKr ratio, 3-HK/3-HAA, QA/3-HAA, and NAM/QA mediated the CRP. KYN/TRP, 3-HK/XA, and NAM/QA explained the relationship for IL-6 and 3-HK/XA and QA/3-HAA for TNF-α. No mediation effect was observed for the other cytokines (indirect effect p > .05). KP metabolites, particularly higher ratios of KYN/TRP, 3-HK/XA, 3-HK/3-HAA, QA/3-HAA, and a lower ratio of NAM/QA, mediated the relationship between inflammation and low muscle mass. Our preliminary cross-sectional data suggest that interventions to alter D3Cr muscle mass may focus on KP metabolites rather than inflammation per se.