title: Contribution of Quadriceps Weakness to Fragility Fracture: A Prospective Study.
abstract: The association between muscle weakness and fracture is not well understood. This study sought to examine the contribution of muscle strength at baseline and change in muscle strength to the observed risk of fragility fracture in older people. The study involved 595 men and 1066 women aged 60+ years (median 69 years) who had been followed for a median of 11 years (range, 4 to 22 years). Quadriceps isometric muscle strength (MS) measured at baseline and biennially was adjusted for height. Femoral neck bone mineral density (FNBMD) was measured by DXA. Low-trauma fracture was ascertained from X-ray reports and interview. The relationship between baseline MS and serial MS and fracture assessed by time-invariant and time-variant Cox's regression models was expressed as hazard ratio (HR) and 95% confidence interval (CI). During the follow-up period, 282 (26%) women and 89 (15%) men sustained a fragility fracture. From age 60 years, women lost 0.28 kg/m (1.6%) of MS per year, whereas men lost 0.39 kg/m (1.5%) of MS per year. In the time-variant model, using serial MS, each 1 SD (4.7 kg/m) lower MS was associated with a 27% increase in the risk of fracture in women (HR 1.27; 95% CI, 1.11 to 1.43); and 46% increase in men (HR 1.46; 95% CI, 1.22 to 1.75). After adjusting for FNBMD, age and prior fracture, history of fall and smoking, HR per SD of lower MS was 1.13 (95% CI, 0.99 to 1.28) for women and 1.35 (95% CI, 1.18 to 1.64) for men. These data indicate that muscle weakness is an independent determinant of fracture risk in men, but not in women. This sex difference suggests that apart from mechanical load effect of muscle on bone, there are other muscle-bone interactions that need to be investigated in future studies. The accuracy of fracture risk prediction for men may be improved by incorporating muscle strength.
authors.affiliation: Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.|Thai Binh University of Pharmacy and Medicine, Thai Binh City, Vietnam.
authors.forename: Hanh M
authors.initials: HM
authors.lastname: Pham
authors.affiliation: Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.|Leeton Medical Centre, Leeton, NSW, Australia.
authors.forename: Nguyen D
authors.initials: ND
authors.lastname: Nguyen
authors.affiliation: Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.|St Vincent's Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Center
authors.affiliation: Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.|St Vincent's Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.|School of Medicine Sydney, University of Notre Dame, Sydney, NSW, Australia.
authors.forename: John A
authors.initials: JA
authors.lastname: Eisman
authors.affiliation: Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.|St Vincent's Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.|School of Public Health and Community Medicine, University of New South Wales (UNSW), Sydney, NSW, Australia.|Centre for Health Technologies, University of Technology Sydney, Sydney, NSW, Australia.
authors.forename: Tuan V
authors.initials: TV
authors.lastname: Nguyen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000378:metabolism; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D018908:Muscle Weakness / Q000000981:diagnostic imaging / Q000503:physiopathology; D011446:Prospective Studies; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography
keywords: BONE MINERAL DENSITY; FRACTURE; OSTEOPOROSIS; QUADRICEPS STRENGTH; TIME-VARIANT ANALYSIS