Cardiorespiratory fitness and future risk of pneumonia: a long-term prospective cohort study.

PURPOSE

We aimed to assess the prospective association of cardiorespiratory fitness (CRF) with the risk of pneumonia.

METHODS

Cardiorespiratory fitness, as measured by maximal oxygen uptake, was assessed using a respiratory gas exchange analyzer in 2244 middle-aged men in the Kuopio Ischemic Heart Disease cohort. We corrected for within-person variability in CRF levels using data from repeat measurements taken several years apart.

RESULTS

During a median follow-up of 25.8 years, 369 men received a hospital diagnosis of pneumonia. The age-adjusted regression dilution ratio of CRF was 0.58 (95% confidence interval: 0.53-0.63). Cardiorespiratory fitness was linearly associated with pneumonia risk. The hazard ratio (95% confidence interval) for pneumonia per 1 standard deviation increase in CRF in analysis adjusted for several risk factors for pneumonia was 0.77 (0.68-0.87). The association remained consistent on additional adjustment for total energy intake, socioeconomic status, physical activity, and C-reactive protein 0.82 (0.72-0.94). The corresponding adjusted hazard ratios (95% confidence intervals) were 0.58 (0.41-0.80) and 0.67 (0.48-0.95) respectively, when comparing the extreme quartiles of CRF levels.

CONCLUSIONS

Our findings indicate a graded inverse and independent association between CRF and the future risk of pneumonia in a general male population.