The effect of sleep position on sleep bruxism in adults with obstructive sleep apnea.

BACKGROUND: Most of the respiratory events in adults with obstructive sleep apnea (OSA) occurs in supine position. It has been reported that the contraction of masseter muscles is dependent on the occurrence of arousals rather than on the occurrence of respiratory events. OBJECTIVES: This study had two aims: (1) to compare the rhythmic masticatory muscle activity (RMMA) index in supine position (RMMA_sup) and in non-supine positions (RMMA_nsup) in adults with OSA; and (2) to determine the associations between RMMA index in both supine position and non-supine positions on the one hand, and several demographic and polysomnographic variables on the other hand. METHODS: One hundred OSA participants (36 females and 64 males; mean age = 50.3 years (SD = 10.5)) were selected randomly from among patients with a full-night polysomnographic recording. RMMA_sup index and RMMA_nsup index were compared using Mann-Whitney U-test. Multivariate linear regression analyses were used to predict RMMA index both in supine and non-supine positions based on several demographic and polysomnographic variables. RESULTS: In patients with OSA, the RMMA_sup index was significantly higher than the RMMA_nsup index (p < .001). RMMA_sup index was significantly associated with the arousal index (p = .002) and arousal index in supine position (p < .001). RMMA_nsup index was only significantly associated with the arousal index in non-supine positions (p = .004). CONCLUSION: Within the limitations of this study, RMMAs occur more frequently in supine position than in non-supine positions in patients with OSA. In both sleep positions, RMMAs are associated with arousals.

Prevalence and risk factors of sleep bruxism in adults with primary snoring: a large-scale polysomnographic study.

STUDY OBJECTIVES: To determine the prevalence and risk factors of sleep bruxism (SB) in adults with primary snoring (PS). METHODS: This study included 292 adults with PS (140 males, 152 females; mean age ± standard deviation = 42.8 ± 12.2 years; mean body mass index ± standard deviation = 26.7 ± 4.7 kg/m2) without previous treatment for snoring. SB was diagnosed based on the frequency of the biomarker of SB: rhythmic masticatory muscle activity (SB when rhythmic masticatory muscle activity ≥ 2 episodes/h). Logistic regression was performed, with SB as the dependent variable and with age, sex, body mass index, and sleep- and respiratory-related polysomnographic parameters as the independent variables to identify the risk factors for SB. RESULTS: The prevalence of SB was 44.6% in adults with PS. Younger age (odds ratio = 0.965 [0.944, 0.987]) and shorter total sleep time (odds ratio = 0.760 [0.609, 0.948]) significantly increased the risk of SB (P < .05). CONCLUSIONS: SB is highly prevalent in adults with PS. Younger age and shorter sleep time are significant risk factors for SB in adults with PS. CLINICAL TRIAL REGISTRATION: Registry: onderzoekmetmensen.nl; Name: A Large Sample Polysomnographic Study on Sleep Bruxism; URL: https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON19947; Identifier: NL8516. CITATION: Li D, Lobbezoo F, Hilgevoord AAJ, de Vries N, Aarab G. Prevalence and risk factors of sleep bruxism in adults with primary snoring: a large-scale polysomnographic study. J Clin Sleep Med. 2024;20(8):1331-1337.