In this population-based, case-control study
we identified patients with a first-time pneumonia-related hospitalization between 1997 and
2005, using health care databases in northern Denmark. For each case, 10 sex- and age-matched
population control subjects were selected from Denmark’s Civil Registration System. We used
conditional logistic regression to compute relative risk (RR) for pneumonia-related hospitalization
among subjects with and without diabetes, controlling for potential confounding factors.