Sex differences in the clinical characteristics of possible REM sleep behavior disorder: a community-based study

Individuals with rapid eye movement sleep behavior disorder (RBD) are considered to be at high risk of neurodegenerative diseases. RBD has been reported to be a male-predominant parasomnia and remains to be characterized in different population settings. We investigated sex-related differences in the prevalence, comorbidities, clinical characteristics, and prodromal neurodegenerative symptoms of possible RBD (pRBD) in a community-based cohort.

The validated RBD Questionnaire-Hong Kong (RBDQ-HK) was used to screen for pRBD among 7314 Chinese older adults (2881 men and 4433 women) in the Beijing Longitudinal Study on Aging (BLSA) II cohort. Demographic information, clinical features, prodromal non-motor symptoms, and subtle motor symptoms were assessed using established questionnaires.

A total of 219 participants aged 55 or above were diagnosed with pRBD, of whom 60.27 % were women. The overall prevalence of pRBD was 3.03 %, with similar rates observed in men (3.06 %) and women (3.01 %). Women with pRBD were more likely to have a lower educational level (p < 0.001), higher body mass index (p = 0.030), and higher prevalence of hypertension (p = 0.044) and cardiovascular disease (p = 0.045). They had more frequent sad dreams (p = 0.009) and poorer sleep quality (p = 0.045), whereas men were more prone to hurt themselves or their bed partners in dreams (p = 0.031 and p = 0.019, respectively). No sex difference was found in non-motor symptoms; however, a greater proportion of men reported reduced arm swing (p = 0.031).

In this community population-based study, we found that female participants with pRBD were less educated and exhibited fewer sleep-related injuries than males, which may lead to underreporting in clinical settings. However, males and females had a similar prevalence of prodromal neurodegenerative symptoms. Longitudinal studies are needed to further evaluate the sex differences in the risk of disease phenoconversion in isolated RBD patients in general populations.