Risk for later rapid eye movement sleep behavior disorder in Parkinson's disease: a 6-year prospective study

Background: Rapid eye movement (REM) sleep behavior disorder (RBD) is recognized worldwide as an early indicator of Parkinson's disease, and it occurs in the later stages of the disease. It is known that idiopathic RBD occurs more frequently in males than in females, but a reliable marker for predicting the development of this disorder after the onset of the motor disability symptoms of Parkinson's disease is yet to be identified. Our objective was to determine whether male sex is a reliable indicator of later development of RBD by studying patients for 6 years.Methods: We registered 89 patients with Parkinson's disease into our study from initially screened 100 consecutive patients by diary questionnaires for 4 weeks. A same sole interviewer interviewed once every 1 to 3 months for 6 years. The final follow-up of 49 patients was included in data analysis.Results: Men exhibited a higher prevalence (57%) among patients with positive rapid eye movement sleep behavior disorder. Male sex and enacting behavior during sleep was significantly different between patients with and without rapid eye movement sleep behavior disorder after 6 years. Multivariate logistic regression analysis revealed that male sex [odds ratio (OR) = 5.301, p = .014, 95% confidence interval (CI) = 1.396-20.13] and enacting behavior during sleep (OR = 0.138, p = .032, 95% CI = 0.023-0.843) were related to RBD after 6 years.Conclusion: Patients with Parkinson's disease exhibit rapid eye movement sleep behavior disorder after the onset of motor symptoms.