| Community-acquired pneumonia is one of the leading causes of morbidity and mortality in older adults. A better understanding of determinants of severe pneumonia requiring hospitalization and its successive outcomes in the community-dwelling elderly is important in order to identify those individuals who are at higher risk of acquiring severe pneumonia infection, thus potentially allowing for appropriate prevention and management. First, we sought to address whether hospital- versus community-based controls are the best choice for case-control studies to identify determinants of hospitalization with hospital-based cases. Then we used community-based controls to examine the relationships of various factors of traditional interest (eg, demographics and comorbidities), factors in the biophysical environment (eg, history of exposures to gases, fumes, chemicals, solvents at work), and ambient air pollutants on hospitalization for severe pneumonia in older adults. Further, we used a prospective cohort study to identify several traditional and other potentially modifiable predictors such as prior immunization history of short-term mortality and rehospitalization in older adults hospitalized for community-acquired pneumonia.;We found that community-based controls were preferred to hospital-based controls for comparison to hospital-based cases. Also, we found that different exposures in the biophysical environmental of older adults such as second hand smoking, occupational or residential exposures to gases, fumes, chemical, solvents, gasoline were associated with hospitalization for community-acquired pneumonia. Similarly, we found that long-term exposure to higher levels of ambient air pollutants, namely, nitrogen dioxide and fine particulate matters, were associated with pneumonia infection and successive hospitalization in older adults. We further found chronic comorbidities were associated with short-term mortality, and sex and vitamin E supplementation were associated with rehospitalization following discharge in older adults hospitalized for community-acquired pneumonia. |
