Sleep bruxism and its associations with insomnia and OSA in the general population of Sao Paulo.

Sleep bruxism (SB) is characterized by recurrent masticatory muscle activity during sleep with occasional tooth grinding. SB can be concomitant with sleep apnea although its association with insomnia is understudied. STUDY OBJECTIVE: Assess the strength of the associations between SB, insomnia and sleep apnea in a general population. METHODS: Data from the 2007 EPISONO general population study (n = 1042; Sao Paulo, Brazil) were reused for the present analyses. The data was collected from polysomnography (PSG) and from a questionnaire. SB could only be assessed as "possible" with self-report questionnaires, but as "definitive" with both self-reports and PSG. Logistic regression and decision tree analyses were performed. RESULTS: Logistic regression analyses revealed that being male, overweight, obese, having an apnea/hypopnea index (AHI) above 30 and insomnia syndrome are among risk factors for SB (prevalence ratio (PR): 1.5-3.3). A high AHI and insomnia syndrome had similar PRs, 2.7 and 2.8, respectively. Decision tree analysis showed that insomnia syndrome contributed to the predictive accuracy of SB self-report (88%). A similar estimate (91%) was observed with SB PSG data. Correspondence analysis illustrated three age profiles in participants: (1) good sleepers aged 20-35 years, (2) females aged 35-50 years with SB and concomitant insomnia syndrome, and (3) participants aged ≥ 50 years with obesity and sleep apnea. CONCLUSIONS: Insomnia is likely a condition associated with SB, especially in middle-age females, while sleep apnea seems age and gender dependent. Such overlap may influence the treatment decision to achieve best outcomes. CLINICAL TRIAL REGISTRATION: EPISONO study; Clinical trials.gov ID # NCT00596713.

Polysomnographic study of the prevalence of sleep bruxism in a population sample.

The goal of the current study was to estimate the prevalence of sleep bruxism (SB) in the general population using a representative sample of 1,042 individuals who answered questionnaires and underwent polysomnography (PSG) examinations. After PSG, the individuals were classified into 3 groups: absence of SB, low-frequency SB, and high-frequency SB. The results indicated that the prevalence of SB, indicated by questionnaires and confirmed by PSG, was 5.5%. With PSG used exclusively as the criterion for diagnosis, the prevalence was 7.4% regardless of SB self-reported complaints. With questionnaires alone, the prevalence was 12.5%. Of the 5.5% (n = 56) with confirmed SB, 26 were classified as low-frequency SB, and 30 as high-frequency. The episodes of SB were more frequent in stage 2 sleep, and the phasic bruxism events were more frequent than tonic or mixed events in all sleep stages in individuals with SB. A positive association was observed between SB and insomnia, higher degree of schooling, and a normal/overweight body mass index (BMI). These findings demonstrate the prevalence of SB in a population sampled by PSG, the gold standard methodology in the investigation of sleep disorders, combined with validated questionnaires.