title: A community study of sleep bruxism in Hong Kong children: association with comorbid sleep disorders and neurobehavioral consequences.
abstract: BACKGROUND
  The prevalence of childhood sleep bruxism (SB) varied from 5% to 46% among various studies. In addition to local facial and dental adverse consequences, accumulating evidence suggests that childhood SB could be associated with comorbid sleep and systemic neurobehavioral disturbances. This study attempted to investigate the prevalence and clinical correlates of SB in a large community sample.
  
  
  METHODS
  This study was part of an ongoing epidemiologic study about sleep problems among Hong Kong Chinese children. A total of 9172 questionnaires were distributed to children of grades 1-6 from 13 randomly selected primary schools. Parents of the children were asked to complete and return the Hong Kong children sleep questionnaire, which aimed to explore the sleep problems and patterns of their children.
  
  
  RESULTS
  Six thousand three hundred and eighty-nine questionnaires with valid answers to SB were received and the response rate was 69.7%. The mean age of the recruited children was 9.2±1.8years (50.6%, boys). The prevalence of SB with teeth grinding frequency more than thrice weekly over the past year was 5.9%. SB was more prevalent among boys with decreasing prevalence across age. SB was associated with chronic medical diseases, sleep-related breathing problem, upper respiratory infection, and other parasomnia features, especially sleep talking (OR (95%CI)=4.07 (2.33-7.11)). Children with SB were more likely noticed by their parents to be hyperactive (OR (95%CI)=1.61 (1.25-2.07)) and bad-tempered (OR (95%CI)=1.69 (1.35-2.12)) and had deterioration in their academic performance (OR (95%CI)=1.22(1.03-1.43)).
  
  
  CONCLUSIONS
  Almost 6% of Hong Kong primary schoolchildren suffered from frequent SB. The condition was most prevalent among young boys. SB was found to be associated with a variety of medical conditions, neuropsychiatric sequelae, and comorbid sleep conditions, especially sleep talking and sleep related breathing problems. Further prospective studies will need to clarify the longitudinal course of childhood SB and its response to treatment.
authors.affiliation: Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: M H B
authors.initials: MH
authors.lastname: Lam
authors.forename: Jihui
authors.initials: J
authors.lastname: Zhang
authors.forename: A M
authors.initials: AM
authors.lastname: Li
authors.forename: Y K
authors.initials: YK
authors.lastname: Wing
mesh_terms: D002648:Child; D002652:Child Behavior; D002675:Child, Preschool; D015897:Comorbidity; D003625:Data Collection; D004522:Educational Status; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D020186:Sleep Bruxism / Q000453:epidemiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology*; D013060:Speech; D011795:Surveys and Questionnaires