Muscle strength and muscle mass in people with long term conditions and multimorbidity: A cross-sectional study of UK Biobank participants

BACKGROUND/OBJECTIVESTo compare muscle strength and muscle mass in individuals with various long-term conditions (LTCs) to those of healthy individuals, using data from the UK Biobank. SUBJECTS/METHODSThis cross-sectional study of 444,420 UK Biobank participants (aged 37 - 73) examined 25 self-reported LTCs ( [≥] 1% prevalence). Multimorbidity was defined as a prevalent LTCs count [≥] 2. Muscle strength was assessed using a handgrip dynamometer, while muscle mass (fat-free mass as a percentage of body weight) was assessed using BIA, DXA, and MRI; all expressed as a percentage of total body weight. Linear regression analyses were conducted to examine how muscle strength and muscle mass varied by LTCs and multimorbidity. RESULTSThe lowest muscle strength was observed in men with rheumatoid arthritis (RA), type 2 diabetes (T2D), stroke, gout, and deep venous thrombosis (-11.8% to -6.1%) lower than the reference group and in women with RA, gout, T2D, coronary heart disease (CHD), and stroke (-11.8% to -6.5%). Muscle mass was lowest in men with T2D, gout, CHD, hypertension, and high cholesterol (-4.7% to -3.1%), and in women with gout, T2D, hiatus hernia, CHD, and hypertension (-6.4% to -4.1%). Trends were consistent across measurements using DXA (n=4,719) and MRI (n=22,901). Muscle strength and muscle mass were lower in people with more LTCs, with a dose-response relationship. CONCLUSIONSThis study demonstrates that muscle strength and muscle mass were lower in people with multiple LTCs and specific conditions. Emphasizing the need for targeted muscle interventions, particularly for those with T2D, RA, gout, and CHD.