Association of Muscle Weakness With Post-Fracture Mortality in Older Men and Women: A 25-Year Prospective Study

Abstract

Osteoporotic fracture increases the risk of premature mortality. Muscle weakness is associated with both increased fracture risk and low bone mineral density (BMD). However, the role of muscle strength in post-fracture mortality is not well understood. This study examines the change of muscle strength measured at quadriceps (QS) before and after fracture and defines the relationship between muscle strength and post-fracture mortality. The study involved 889 women and 295 men (who were participating in the Dubbo Osteoporosis Study) who had at least one low-trauma fracture (ascertained from X-ray reports) after the age of 50 years. Median follow-up time was 11 years (range 1 to 24). To determine the change in muscle strength before and after a fracture, we selected a subset of 344 women and 99 men who had had at least two muscle strength measurements before the fracture event and a subset of 407 women and 105 men who had had at least two measurements after the fracture. During the follow-up period, 366 (41.2%) women and 150 (50.9%) men died. The annual rate of decrease in height-adjusted muscle strength before fracture was 0.27 kg/m (1.85%) in women and 0.40 kg/m (1.79%) in men. Strength loss after fracture was not significantly different from that before fracture. In women, after adjusting for baseline age and BMD, each SD (5 kg/m) lower height-adjusted pre- and post-fracture quadriceps strength was associated with a 27% (hazard ratio [HR] = 1.27; 95% confidence interval [CI] 1.07, 1.50) and 18% (HR = 1.18; 95% CI 1.01, 1.38) increase in post-fracture mortality risk, respectively. Similarly, in men, each SD (5 kg/m) lower height-adjusted pre- and post-fracture QS was associated with increased mortality before fracture (HR = 1.33; 95% CI 1.09, 1.63) and after fracture (HR = 1.43; 95% CI 1.16, 1.78). Muscle weakness accounted for 15% (95% CI 0.05, 0.24) of premature deaths after fracture in women and 23% (95% CI 0.11, 0.35) in men. These results indicate that in the older individuals, lower muscle strength is an independent risk factor for post-fracture mortality. © 2017 American Society for Bone and Mineral Research.

Mortality Risk Among Older People Who Did Versus Did Not Sustain a Fracture: Baseline Prefracture Strength and Gait Speed as Predictors in a 15-Year Follow-Up

“…In the current study, participants with lower pre-fracture gait speed and muscle strength had pronounced mortality risk during the first post-fracture year compared to time without fracture exposure. The current results extend earlier findings on the role of pre-fracture muscle strength in post-fracture survival 17,18,18 by including non-fracture time (no fracture during the follow-up and time The association of gait speed and muscle strength with mortality risk has been reported several times [30][31][32] . However, it is unclear, what underlies these associations 31 .…”

“…To our knowledge, only a few studies have investigated the association between objectively measured pre-fracture muscle strength and subsequent survival. According to two earlier studies, participants with higher knee extension strength before a bone fracture had lower post-fracture mortality risk than those with lower muscle strength 17,18 . However, in those studies, the study population was composed solely of individuals who had sustained a fracture, and hence we do not know whether the predictive power of higher muscle strength on survival is different after fracture compared to time without fracture.…”

Nutrition and exercise in Pompe disease

“…Muscle weakness and low BMD are a dangerous combination for they lead to an increased fall risk and subsequent fracture risk (45,46). A femur or hip fracture in a patient who is very weak can be the seminal event resulting in a permanent loss of ambulation and can even lead to higher mortality risk (47). To what extent the low BMD seen in some Pompe patients is due to hypodynamia, low vitamin D status, and/or low protein intake is unclear, but all are likely contributors to some extent in specific patients and all are modifiable.…”

Osteoporosis in Older Persons: Old and New Players

“…Osteoporotic fractures are associated with increased morbidity, loss of independence, and a 20% increase in mortality at 1 year . The prevalence of these poor outcomes is higher when osteoporosis is associated with muscle weakness . Hip fractures carry the greatest risks and are associated with between 8% and 36% increased mortality at 1 year .…”

“…21 The prevalence of these poor outcomes is higher when osteoporosis is associated with muscle weakness. 21 Hip fractures carry the greatest risks and are associated with between 8% and 36% increased mortality at 1 year. 22 Osteoporosis case-finding, fracture risk calculation, muscle assessment, and appropriate treatment is key to the health of older adults worldwide.…”