Association between neurodegenerative diseases and pneumonia: a retrospective population-based study.

Purpose: The association between pneumonia and neurodegenerative diseases (NDs) has never been reported in detail. We address this relationship with reference to the general population.

Methods: Using Taiwan's National Health Insurance Research Database to identify a pneumonia cohort (including the typical and atypical), we established an ND cohort of 19,062 patients and a non-ND cohort of 76,227 people. In both cohorts, the risk of pneumonia was measured using multivariable Cox proportional hazards models.

Results: The adjusted hazard ratio (aHR) (95% confidence interval [CI]) for the pneumonia cohort was 2.10 (1.96-2.24), regardless of age, sex, comorbidities or drug use in the ND cohort. The aHR (95% CI) for adults aged 20-49 years was 2.08 (1.58-2.75), men 2.20 (2.01-2.40). However, older subjects were at greatest risk of pneumonia, (3.41 [2.99-3.88]) if the 20-49 years age group is used as the reference. For the ND and non-ND cohorts, those with comorbidities (with the exception of hyperlipidemia) had higher risk; aHR (95% CI) 2.35 (2.30-2.52). The aHR (95% CI) for those without comorbidities is 3.28 (2.52-4.26). No significant difference was observed in incidence of pneumonia between those who were and were not using statin medications; the aHR (95% CI) was 1.03 (0.93-1.14).

Conclusion: The ND cohort had a higher risk of pneumonia, regardless of age, sex, comorbidities or statin use. The risk of pneumonia was higher in elderly and male patients in the ND cohort.