Abstract P305: Daily Walking Time and Pneumonia Mortality Among Elderly With/Without Medical History of Myocardial Infarction or Stroke

Abstract

Several studies report that daily walking reduces the risk of pneumonia. However, the elderly often experience underlying chronic diseases such as myocardial infarction (MI) or stroke which also increase the risk of pneumonia; thus, the association of walking with pneumonia may merely be a result of confounding of the underlying conditions. Therefore, we explored the links between daily walking and pneumonia mortality stratified by the presence of medical histories in 22,280 Japanese elderly (9,067 men and 13,213 women) aged 65 to 79 years from 1988-1990. The Cox proportional hazards model was used to calculate hazard ratio (HR) and 95% confidence interval (CI) for pneumonia mortality (ICD10: J9-18, J69) adjusted for age, sex, and possible confounders. P for trend was calculated across the categories of walking time. After a median of 11.9 years’ follow-up, 1,203 participants died of pneumonia. In participants without a medical history of MI or stroke, the HR of pneumonia mortality in participants who had walked at baseline for ≥1 h/day was 0.73 (95% CI, 0.62-0.85; P for trend <0.001), compared with those who had walked for 0.5 h/day. Participants with a medical history of MI who walked for ≥1 h/day also showed significantly decreased risk of pneumonia mortality (HR, 0.49; 95% CI, 0.27-0.92; P for trend = 0.01). No significant associations were found among participants with a medical history of stroke (HR, 0.82; 95% CI, 0.39-1.72), although P for trend was statistically significant (P for trend = 0.003). However, the HR of pneumonia mortality in participants who had walked at baseline for <0.5 h/day was 1.46 (95% CI, 1.19-1.78) in participants without a medical history of MI or stroke, 1.06 (95% CI, 0.46-2.25) in participants with a medical history of MI, and 2.83 (95% CI, 1.35-5.95) in participants with a medical history of stroke. Our findings suggest that longer walking time may be beneficial in reducing the risk of pneumonia mortality in elderly populations.