To explore the complex associations of sarcopenia with lung function, and risks of incident respiratory disease (including its subtypes: chronic obstructive pulmonary disease [COPD], asthma, and interstitial lung disease [ILD]), as well as to explore the potential inflammatory and metabolic pathways.

Prospective cohort study.

We assembled data from 317,628 adults enrolled in the UK Biobank.

Sarcopenia status was defined using the European Working Group on Sarcopenia in Older People 2 criteria. Lung function was assessed via a spirometer. The incident respiratory disease was ascertained through linked hospital data over a median follow-up of 14 years.

Both probable sarcopenia and confirmed/severe sarcopenia were consistently associated with poorer lung function and a higher risk of incident respiratory disease. For instance, compared with their non-sarcopenic counterparts, participants with probable sarcopenia exhibited a significantly higher risk (P < 0.001) of respiratory disease (hazard ratio [HR] = 1.30; 95% confidence interval [CI]: 1.26, 1.36), COPD (HR = 1.37; 95% CI: 1.24, 1.50), asthma (HR = 1.35; 95% CI: 1.23, 1.48), and ILD (HR = 1.74; 95% CI: 1.48, 2.04). Furthermore, inflammatory markers and metabolites partially mediated the associations between probable sarcopenia and incident respiratory disease, with C-reactive protein (5.2 %–12.9 %) and albumin (2.6%–8.0%) showing relatively higher mediation proportions.

Sarcopenia, even at the probable stage, was significantly associated with an increased risk of incident respiratory disease, and inflammatory and metabolic mechanisms may underlie these associations. Our findings highlight the importance of early prevention and management of sarcopenia for preserving respiratory health.