Interrelationships among handgrip strength, body composition, physical activity, and quality of life in adults with cystic fibrosis: A cross-sectional study

Background: In individuals with cystic fibrosis (CF), lean mass and muscle strength are important predictors of clinical outcomes. This study evaluated associations among body composition, handgrip strength, muscle quality, physical activity, and health-related quality of life in CF. Methods: This observational, cross-sectional study included 27 adults with CF and 24 age-matched healthy controls. Body composition was assessed using dual-energy x-ray absorptiometry, physical activity by self-reported questionnaire, strength by handgrip dynamometry, and quality of life by the CF Quality of Life-Revised (CFQ-R) questionnaire. Muscle quality was defined as handgrip strength divided by appendicular lean mass. Analyses included t- tests and Pearson or Spearman correlations. Results: Demographics, body composition, handgrip strength, and muscle quality were similar between those with CF and controls. Among those with CF, muscle quality was positively associated with total physical activity score (r = 0.49, P = 0.009). Handgrip strength was positively associated with lean mass (r = 0.86, P < 0.001) and bone mineral density (r = 0.64, P < 0.001). Regarding CFQ-R, lean mass was positively associated with body image and emotion (r = 0.41, P = 0.03), and body fat was associated with lower physical functioning (r = −0.63, P = 0.004), greater treatment burdens (r = −0.49, P = 0.01), and worse digestive health (r = −0.45, P = 0.02). Conclusion: As the CF population ages, these data support continued efforts to promote physical activity and improve body composition for enhanced quality of life while also highlighting the value of integrating accessible measures of muscle function and quality into routine clinical care.