Introduction: The respiratory muscle strength regulates the effectiveness of coughing, which clears the airways and protects people from pneumonia. Sarcopenia is an aging-related loss of muscle mass and function, the worsening of which is associated with malnutrition. The loss of respiratory and swallowing muscle strength occurs with aging, but its effect on pneumonia is unclear. This study aimed to determine the risks of respiratory muscle weakness on the onset and relapse of pneumonia in older people in conjunction with other muscle-related factors such as malnutrition. Methods: We conducted a longitudinal study with 47 pneumonia inpatients and 35 non-pneumonia controls aged 70 years and older. We evaluated the strength of respiratory and swallowing muscles, muscle mass, and malnutrition (assessed by serum albumin levels and somatic fat) during admission and confirmed pneumonia relapse within 6 months. The maximal inspiratory and expiratory pressures determined the respiratory muscle strength. Swallowing muscle strength was evaluated by tongue pressure. Bioelectrical impedance analysis was used to evaluate the muscle and fat mass. Results: The respiratory muscle strength, body trunk muscle mass, serum albumin level, somatic fat mass, and tongue pressure were significantly lower in pneumonia patients than in controls. Risk factors for the onset of pneumonia were low inspiratory respiratory muscle strength (odds ratio [OR], 6.85; 95% confidence interval [CI], 1.56–30.11), low body trunk muscle mass divided by height2 (OR, 6.86; 95% CI, 1.49–31.65), and low serum albumin level (OR, 5.46; 95% CI, 1.51–19.79). For the relapse of pneumonia, low somatic fat mass divided by height2 was a risk factor (OR, 20.10; 95% CI, 2.10–192.42). Discussion/Conclusions: Respiratory muscle weakness, lower body trunk muscle mass, and malnutrition were risk factors for the onset of pneumonia in older people. For the relapse of pneumonia, malnutrition was a risk factor.

Generally, weak muscle power is associated with high mortality. We aimed to evaluate the unknown association between % predicted value forced vital capacity (FVC% predicted) and mortality in asymptomatic older people, and the impact of muscle power on this association. We analyzed the Tsurugaya cohort that enrolled Japanese people aged ≥70 for 15 years with Cox proportional hazards model. Exposure variables were FVC% predicted and leg power. The outcome was all-cause mortality. The subjects were divided into quartiles by FVC% predicted or leg power, or into two groups by 80% for FVC% predicted or by the strongest 25% for leg power. Across 985 subjects, 262 died. The males with lower FVC% predicted exhibited higher mortality risks. The hazard ratio (HR) was 2.03 (95% CI 1.30–3.18) at the lowest relative to the highest groups. The addition of leg power reduced the HR to 1.78 (95% CI 1.12–2.80). In females, FVC% predicted under 80% was a risk factor and the HR was 1.67 (95% CI 1.05–2.64) without the effect of leg power. In FVC% predicted <80% males HRs were 2.44 (95% CI 1.48–4.02) in weak and 1.38 (95% CI 0.52–3.64) in strong leg power males, relative to ≥80% and strong leg power males. Low FVC% predicted was associated with high mortality with potential unfavorable effects of weak leg power in males.

Impaired % predicted value forced vital capacity (% FVC) is related to higher all-cause mortality in aged adults, and strong muscle force may improve this relationship. A muscle disease, sarcopenia, causes higher mortality. We aimed to identify the unknown disease that relates impaired % FVC with higher mortality in aged adults among the three major leading causes of death, and the effect of strong leg force on this relationship. Cox proportional hazard model analyzed the longitudinal Tsurugaya cohort that registered 1048 aged Japanese for 11 years. The primary outcome was the relationship between % FVC and mortality by cancer, cardiovascular disease, or pneumonia. Exposure variables were % FVC or leg force divided by 80% or median values, respectively. The secondary outcome was the effects of leg force on the relationship. Among the diseases, % FVC < 80% was related only to higher pneumonia mortality (hazard ratio [HR], 4.09; 95% CI, 1.90–8.83) relative to the % FVC ≥ 80% group before adjustment. Adding the leg force as an explanatory variable reduced the HR to 3.34 (1.54–7.25). Weak leg force might indicate sarcopenia, and its prevention may improve higher pneumonia mortality risk related to impaired % FVC, which we may advise people in clinical settings.

No abstract