Dementia and hip fracture co-occur in older people. However, the early interplay between cognitive function and musculoskeletal parameters remains unclear. This study aimed to assess: (i) longitudinal associations between cognitive decline and declines in bone mass, muscle strength, and physical performance; and (ii) the impact of impaired cognition (defined as a Teng Modified Mini-Mental State Examination [3MS] score <80) at Year 5 (Y5), clinically relevant cognitive decline (defined as a decline of ≥5 points) between baseline and Y5, and the combination of impairment and decline on the risk of subsequent fracture after Y5 (mean follow-up 10.0 years).
A total of 4263 men aged ≥ 65 years from the Osteoporotic Fractures in Men (MrOS) Study with data available on cognitive function at baseline and Y5 were included. Fractures were adjudicated by centralized physician review of radiology reports. The longitudinal associations between cognitive decline and the changes in total hip BMD, grip strength, gait speed, and chair stands between baseline and Y14 were estimated using mixed-effects models. Fracture risk after Y5 was estimated using Cox models.
From baseline to Y14, there were significant annual declines in 3MS (0.5%), BMD (0.5%), grip strength (1.8%), gait speed (1.5%), and chair stands (1.8%). Cognitive decline was significantly associated with a decline in all musculoskeletal parameters (Figure), independent of age and other risk factors. Between baseline and Y5, 23% of participants experienced clinically relevant cognitive decline, and 4.6% scored <80 at Y5. After Y5, 18% sustained a fracture. Cognitive impairment was associated with 41% increased fracture risk (HR:1.41; 95%CI: 1.00-1.98) compared to 3MS≥80. However, this association was only apparent in those who also had clinically relevant declines (1.55;1.07-2.24).
Cognitive decline leading to cognitive impairment increases fracture risk. it is important to assess bone health, falls, and fracture risk in older men with cognitive impairment.