Handgrip Strength: Associations with Clinical Variables, Body Composition, and Bone Mineral Density in Adults with Cystic Fibrosis

Abstract

Background: Loss of fat-free mass (FFM) is associated with an increase in morbidity and mortality in cystic fibrosis (CF) patients. Handgrip strength (HGS) measures muscle function and may be associated with clinical parameters with prognostic value. Our objectives were to evaluate muscle strength through HGS in CF patients and to determine if there are any associations with respiratory clinical variables, FFM, and bone mineral density (BMD). Methods: A cross-sectional study conducted in clinically stable patients. We evaluated muscle function through HGS, respiratory function—forced expiratory volume in 1 s (FEV1) (%), forced vital capacity (FVC) (%), bronchorrhea, annual exacerbations, and body composition (FFM and FFM index, FFMI: fat-free mass in kg/height in m2) and Bone Mineral Density (BMD) through densitometry (DXA). Results: The study included 53 CF patients (58.5% females, mean age 28.3 ± 8.1, body mass index (BMI) 21.7 ± 3.4). The mean values for dynamometry were 40.2 ± 8.1 kg in males and 23.1 ± 7.0 kg in women, being 20.8% below the 10th percentile. Patients with lower muscle strength showed significantly more exacerbations and lower FEV1% and FVC%, as well as lower BMI, worse BMD (g/cm2), T-score, and Z-score. A significant and positive correlation was found between the mean and maximum dynamometry values and age, FVC%, BMI, FFMI, FFM (kg), and BMD. Conclusions: For adults with CF, HGS is a practical tool for assessment of health status. Low values reflect poor nutritional status and are associated with poor respiratory function, low fat-free mass and low bone mineral density.

Clinical relevance of low bone density in cystic fibrosis adult patients: A pilot study

“…[ 15 ] CF patients with lower muscle strength have significantly worse BMD. [ 16 ] The association between low BMD and airway clearance impairment and/or decline of respiratory function has not been demonstrated. [ 11 , 13 , 17 , 18 ] Some authors consider that osteoporosis may be a barrier to lung transplantation.…”

Cystic Fibrosis Bone Disease: The Interplay between CFTR Dysfunction and Chronic Inflammation

“…Indeed, children with cystic fibrosis already have bone alterations [ 54 , 55 , 56 , 57 , 58 ] which increase with age [ 59 ]. The progressive bone loss [ 48 ] in cystic fibrosis patients correlates with reduced lung function [ 60 , 61 , 62 ], recurrent pulmonary exacerbations [ 63 ], inflammation [ 64 ] and reduced muscle strength [ 65 ]. Yet, these correlations and a reduced bone mineral density are not always identified in all cystic fibrosis populations [ 45 ], suggesting that other factors may also play a role in the development of bone loss in these patients [ 66 ].…”