Bidirectional association between Parkinson's disease and obstructive sleep apnea: a cohort study.

STUDY OBJECTIVES: Chronic intermittent hypoxia due to obstructive sleep apnea (OSA) causes oxidative stress, which may contribute to the pathophysiology of Parkinson's disease (PD). However, the bidirectional relationship between PD and OSA has not been satisfactorily established. The objective of this study was to try to estimate whether there is a bidirectional relationship between PD and OSA through a retrospective cohort study on South Korean population.

METHODS: This study used data from the Korean National Health Information Database of the National Health Insurance Service, which contains data from 3.5 million individuals evenly distributed. In Study 1, patients with OSA were matched in a 1:2 ratio with non-OSA controls. In Study 2, patients with PD were matched in a 1:2 ratio with non-PD controls. A stratified Cox proportional hazard model was used to calculate hazard ratios (HR).

RESULTS: In Study 1, which included 6,396 OSA patients and 12,792 non-OSA controls, the incidence of PD per 10,000 person-years (PY) was 11.59 in the OSA group and 8.46 in the non-OSA group. The OSA group demonstrated a 1.54-fold higher incidence of PD than the non-OSA group (95% confidence interval, 1.14-2.07, P<0.05). In Study 2, which included 3,427 PD patients and 6,854 non-PD controls, the incidence of OSA per 10,000 PY was 14.97 in the PD group and 7.72 in the non-PD group. The PD group demonstrated a 1.92-fold higher incidence for OSA than the non-PD group (95% CI =1.32-2.78, P<0.05).

CONCLUSIONS: This study supports a possible bidirectional relationship between PD and OSA.