Clinical significance of periodic limb movements during sleep: the HypnoLaus study

Periodic limb movements during sleep (PLMS) are prevalent in the general population, but their impact on sleep and association with cardiometabolic disorders are a matter of debate.

Data from 2162 participants (51.2% women, mean age 58.4 ± 11.1 years) of the population-based HypnoLaus study (Lausanne, Switzerland) were collected. Subjective sleep complaints and habits were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale (ESS). Participants underwent a full polysomnography (PSG) at home and were evaluated for the presence of hypertension, diabetes, and metabolic syndrome.

Participants with a PLMS index (PLMSI) > 15/h (28.6% of the sample) had longer subjective sleep latency (18.6 ± 17.2 vs. 16.1 ± 14.3 min, p = 0.014) and duration (7.1 ± 1.2 vs. 6.9 ± 1.1 h, p < 0.001) than participants with PLMSI ≤ 15/h. At the PSG, they spent more time in stage N2 sleep (49.0 ± 11.2 vs. 45.5 ± 9.8%, p < 0.001), less in stage N3 (17.6 ± 8.2 vs. 20.6 ± 8.4%, p < 0.001) and in REM sleep (20.3 ± 6.4 vs. 22.4 ± 6.0%, p < 0.001), and exhibited longer REM latency (104.2 ± 70.2 vs. 91.7 ± 58.6 min, p < 0.001) and higher arousal index (26.5 ± 12.3 vs. 19.2 ± 9.7 n/h, p < 0.001). Participants with a PLMSI > 15/h had a lower ESS scores and higher prevalence of hypertension, diabetes, and metabolic syndrome. Multivariate analysis adjusting for confounding factors confirmed the independent association of PLMSI > 15/h with subjective sleep latency and duration, and with objective sleep structure disturbances. However, the associations with sleepiness and cardiovascular risk factors disappeared.

In our large middle-age European population-based sample, PLMSI > 15/h was associated with subjective and objective sleep disturbances but not with sleepiness, hypertension, diabetes, or metabolic syndrome.