Risk factors for probable REM sleep behavior disorder

Objective: To examine risk factors for REM sleep behavior disorder (RBD) in a large-scale community-based study. Methods: This community-based study included 12,784 Chinese adults (10,556 men and 2,228 women, aged 24 years or older) who were free of Parkinson disease and dementia in 2012. Probable RBD (pRBD) status was determined by a validated questionnaire (Chinese RBD questionnaire-Hong Kong) in 2012. Potential risk factors - including age, sex, smoking, socioeconomic status, physical activity, obesity, consumption of tea (surrogate for caffeine intake) and alcohol, serum concentrations of lipids and glucose, and chronic disease status - were assessed in 2006. Logistic regression was used to calculate odds ratios and 95% confidence intervals and to test differences in prevalence of pRBD across exposures. Results: Prevalence of pRBD was 5.9% in men and 4.1% in women. In the fully adjusted model, risk factors that were significantly associated with a higher risk of having pRBD included lower education level, coal mining and other blue collar occupation, lower physical activity level, diabetes or prediabetes, lower body mass index, head injury, higher low-density lipoprotein level, and chronic olfactory and taste dysfunction. In sensitivity analyses, restricting to pRBD cases with symptom onset within 1 year or excluding coal miners or those with history of head injury generated similar results. Conclusion: We found several potential risk factors for pRBD, including socioeconomic status, head injury, olfactory and taste dysfunction, and various cardiovascular risk factors. Future prospective studies to establish the temporal relationship between these potential risk factors and RBD are warranted.