The prevalence and impact on sleep of periodic limb movements during sleep in the elderly

Abstract

Introduction Periodic limb movements during sleep (PLMS) are common in the elderly population, but there remains much controversy over the clinical significance of PLMS. The aim of this study was to investigate the prevalence and impact on sleep of PLMS in the elderly population in South Korea. Materials and methods A cross-sectional and community-based study was conducted in Jukjeon-dong, South Korea, from November 2010 to January 2012. Among 6959 individuals aged 60 years or older, 696 subjects were selected using systemic random sampling. All the subjects were invited to visit a hospital for overnight polysomnographic study. Periodic leg movements (PLM) were scored according to the American academy of sleep medicine (AASM) manual. Subjective sleep complaints were assessed using Pittsburgh Sleep Quality Index (PSQI), and insomnia was diagnosed according to the criteria of DSM-IV-TR. Results Of the 696 subjects sampled, 348 subjects (135 male, 213 female, mean age 68.3+/-5.6 years) were analyzed and final response rate was 50.0%. The prevalence of PLMS (PLM index > 15) was 29.3% (male 24.1%, female 33.5%). There was no significant effect of PLM severity for polysomnographic sleep parameters and subjective sleep quality. Diagnosis of insomnia was significantly higher in individuals with PLM arousal index (PLMA) >=5 than in those with PLMA ¥ o 2 = 4.69, P 0.05). The subjects with insomnia, compared to ones without it, showed higher PLMA, lower body mass index (BMI), lower apnea–hypopnea index (AHI) and women predominance. After adjustment for sex, BMI and AHI, higher PLMA was independently related with insomnia diagnosis (adjusted odds ratio 2.03 [1.01–4.08]). Conclusion The PLMS prevalence of 29.3% in this study was comparable to those of previous studies. PLMS has little impact on nocturnal sleep quality and daytime sleepiness, but PLMA iA5 may increase the occurrence of insomnia more than twice.