Handgrip strength and risk of common infections and sepsis: Two prospective cohorts with proteomic mediation analysis

Background
Recent evidence links adiposity with the risk of severe infections, but whether muscle strength may also be an independent risk factor is less studied. We investigated the association between handgrip strength and risk of common infections and sepsis and explored potential mediation by plasma proteomic biomarkers.
Methods
We analyzed data from 405,451 UK Biobank participants and replicated the main findings in 4474 Chinese adults from the Hong Kong Osteoporosis Study (HKOS). Baseline handgrip strength was measured by a dynamometer. Cox models were used to estimate its association with incidence of pneumonia, urinary tract infection (UTI), skin infection, and sepsis, adjusting for sociodemographic, lifestyle, and health-related factors. Mediation analyses were performed using 2912 plasma proteins in a UK Biobank subsample (n = 42,414) to identify biological pathways.
Results
In UK Biobank (median follow-up 13.6–15.3 years), lower handgrip strength was associated with significantly increased risk of pneumonia (hazard ratio per 5-kg decrement=1.10; 95% CI=1.09–1.11), UTI (1.10; 1.09–1.11), skin infection (1.05; 1.04–1.05), and sepsis (1.08; 1.07–1.10). Associations were largely consistent in HKOS, and the relative risks associated with low grip strength were generally most pronounced in underweight individuals. GDF15 and PLAUR were identified as the most important proteins which mediated 12–14% of these associations.
Conclusion
Low handgrip strength is associated with increased risks of common infections and sepsis, particularly in underweight individuals, with partial mediation by proteins related to inflammation and immune-related pathways. Handgrip strength assessment may provide prognostic value beyond body mass index for clinical risk stratification.