Strong Relation Between Muscle Mass Determined by D3-creatine Dilution, Physical Performance, and Incidence of Falls and Mobility Limitations in a Prospective Cohort of Older Men

Abstract

Background: Direct assessment of skeletal muscle mass in older adults is clinically challenging. Relationships between lean mass and late-life outcomes have been inconsistent. The D3-creatine dilution method provides a direct assessment of muscle mass.

Methods: Muscle mass was assessed by D3-creatine (D3Cr) dilution in 1,382 men (mean age, 84.2 years). Participants completed the Short Physical Performance Battery (SPPB); usual walking speed (6 m); and dual x-ray absorptiometry (DXA) lean mass. Men self-reported mobility limitations (difficulty walking 2-3 blocks or climbing 10 steps); recurrent falls (2+); and serious injurious falls in the subsequent year. Across quartiles of D3Cr muscle mass/body mass, multivariate linear models calculated means for SPPB and gait speed; multivariate logistic models calculated odds ratios for incident mobility limitations or falls.

Results: Compared to men in the highest quartile, those in the lowest quartile of D3Cr muscle mass/body mass had slower gait speed (Q1: 1.04 vs Q4: 1.17 m/s); lower SPPB (Q1: 8.4 vs Q4: 10.4 points); greater likelihood of incident serious injurious falls (odds ratio [OR] Q1 vs Q4: 2.49, 95% confidence interval [CI]: 1.37, 4.54); prevalent mobility limitation (OR Q1 vs Q4,: 6.1, 95% CI: 3.7, 10.3) and incident mobility limitation (OR Q1 vs Q4: 2.15 95% CI: 1.42, 3.26); p for trend < .001 for all. Results for incident recurrent falls were in the similar direction (p = .156). DXA lean mass had weaker associations with the outcomes.

Conclusions: Unlike DXA lean mass, low D3Cr muscle mass/body mass is strongly related to physical performance, mobility, and incident injurious falls in older men.

Keywords: Falls; Functional performance; Muscle; Sarcopenia.

Figure 1.

Correlations between D₃Cr dilution measures of muscle mass (kg) and D₃Cr muscle mass/body mass with DXA-derived measures of lean mass and fat (total body lean mass, ALM, ALM/ht², ALM/body mass, percent fat) and BMI in older men. ALM = Appendicular lean mass; BMI = Body mass index; DXA = Dual x-ray absorptiometry.

Figure 2.

Adjusted* means of walking speed over 6 m, lower extremity power, SPPB score, and grip strength across quartiles of D₃Cr muscle mass/body mass or ALM/ht². *Adjusted for age, clinical center, race, alcohol use, smoking, congestive heart failure, chronic obstructive pulmonary disease, diabetes, myocardial infarction, physical activity, exhaustion, and cognitive function. Quartile cut-points for D₃Cr muscle mass/body mass: Q1: <0.27 Q2: ≥0.27–0.30, Q3: ≥0.30–0.34, Q4: ≥0.34. Quartile cut-points for ALM/ht² (kg/m²): Q1: <6.9, Q2: ≥6.9–<7.5, Q3: ≥7.5–<8.1, Q4: ≥8.1. ALM = Appendicular lean mass.

Figure 3.

Multivariate-adjusted* likelihood (odds ratio, 95% CI) of prevalent function limitations, by D₃Cr muscle mass/body mass and DXA ALM/ht². *Model is adjusted for age, clinical center, race, alcohol use, smoking, congestive heart failure, chronic obstructive pulmonary disease, diabetes, myocardial infarction, physical activity, exhaustion, and cognitive function. Quartile cut-points for D₃Cr muscle mass/body mass: Q1: <0.27 Q2: ≥0.27–0.30, Q3: ≥0.30–0.34, Q4: ≥0.34. Quartile cut-points for ALM/ht2 (kg/m²): Q1: <6.9, Q2: ≥6.9–<7.5, Q3: ≥7.5–<8.1, Q4: ≥8.1. SD for D₃Cr muscle mass/body mass: 0.048; SD for ALM/ht²: 0.87. ALM = Appendicular lean mass.

Figure 4.

Multivariate-adjusted* likelihood (odds ratio, 95% CI) of incident recurrent falls, serious injurious falls and mobility limitation, by D₃Cr muscle mass/body mass and DXA ALM/ht². *Model is adjusted for age, clinical center, race, alcohol use, smoking, congestive heart failure, chronic obstructive pulmonary disease, diabetes, myocardial infarction, physical activity, exhaustion, and cognitive function. Quartile cut-points for D₃Cr muscle mass/body mass in falls models: Q1: <0.27 Q2: ≥0.27–0.30, Q3: ≥0.30–0.34, Q4: ≥0.34. Quartile cut-points for ALM/ht² (kg/m²) in falls models: Q1: <6.9, Q2: ≥6.9–<7.5, Q3: ≥7.5–<8.1, Q4: ≥8.1. Quartile cut-points for D₃Cr muscle mass/body mass in mobility limitations model: Q1:<0.28, Q2: ≥0.28–<0.31, Q3: ≥0.31–<0.35, Q4: ≥0.35. Quartile cut-points for ALM/ht2 (kg/m²) in mobility limitations models: Q1: <6.9, Q2: ≥6.9–<7.5, Q3: ≥7.5–<8.0, Q4: ≥8.0. For falls models: SD for D₃Cr muscle mass/body mass: 0.048; SD For ALM/ht2: 0.87 For mobility limitations models: SD for D₃Cr muscle mass/body mass: 0.046; SD for ALM/ht²: 0.855. ALM = Appendicular lean mass; DXA = Dual x-ray absorptiometry.