CNS infections, sepsis and risk of Parkinson's disease

Background Neuroinflammation may play an important role in the aetiology of Parkinson's disease ( PD); however, little is known about infections in relation to future PD risk. Methods We conducted a register-based nested case-control study in Sweden to examine infections of the central nervous system (CNS) and sepsis in relation to PD with 18 648 patients and 93 240 matched controls. We defined the index date as the date of first recorded PD diagnosis in the Swedish Patient Register. Results Overall, PD patients were more likely to have a previous hospitalization for CNS infections [odds ratio (OR) = 1.5, 95% confidence interval (CI): 1.2-1.9] or sepsis (OR = 1.6, 95% CI: 1.4-1.7) than controls, largely due to hospitalizations in the year before PD identification (CNS infections: OR = 3.0, 95% CI: 1.6-5.7; sepsis: OR = 3.5, 95% CI: 3.0-4.0). However, we found that subjects with multiple CNS infections at least 5 years before the index date had higher PD occurrence than those without CNS infections (OR = 3.3, 95% CI: 1.4-8.2), whereas the corresponding OR for sepsis was 1.4 (95% CI: 0.8-2.4). After the index date, PD patients were more likely to be hospitalized for CNS infections [hazard ratio (HR) =1.8, 95% CI: 1.2-2.7] or sepsis (HR = 2.2, 95% CI: 2.1-2.4) than controls. Conclusions This study provides preliminary evidence for an association between CNS infections, but not sepsis, and a higher future risk of PD. It also shows that PD patients were more prone to CNS infections and sepsis than controls.