Association of sleep abnormalities in older adults with risk of developing Parkinson’s disease

Background Parkinson’s disease (PD) is associated with abnormalities of sleep macro- and microstructure as measured using polysomnography (PSG). Whether sleep abnormalities precede the development of PD is unknown. This study investigated the association between PSG measured sleep abnormalities in older adults and the risk of developing PD. Methods 2,770 men aged 67 years or older from the ancillary sleep study of the Osteoporotic Fractures in Men Study (MrOS), a population-based cohort from the USA, who were free from PD at baseline (December 2003 – March 2005) and in whom there was PSG data available, were included in this analysis. Incident PD was based on a clinical diagnosis from a medical professional. Multivariable logistic regression was used to estimate odds ratios (OR) for incident PD by quartiles of PSG measures. Findings During a median follow-up of 10.1 years, 70 (2.5%) cases of incident PD were identified. Longer total sleep time, lower rapid eye movement sleep (REM) percentage, a lower α/θ ratio during non-REM sleep and higher minimum oxygen saturations during REM sleep, were independently associated with an increased risk of developing PD during follow-up. Conversely, a higher awakening index was independently associated with a decreased risk of developing PD. The OR for the highest risk quartiles compared to the lowest risk quartiles, ranged from 2.3 to 4.0 ( P < 0.05). The associations remained significant when incident PD cases occurring within the first two years of follow-up were excluded from the analyses. Conclusions Macro- and microstructural sleep abnormalities precede the development of PD by several years and can identify individuals at high risk of developing PD in the future. Future studies are needed to determine whether sleep abnormalities represent preclinical markers of PD or causal risk factors.