title: A community-based study of insomnia in Hong Kong Chinese children: Prevalence, risk factors and familial aggregation.
abstract: OBJECTIVE
  There has been limited data on familial aggregation of insomnia. We aimed to explore the prevalence, risk factors and familial aggregation of childhood insomnia with a large community-based sample.
  
  
  METHODS
  A community-based epidemiologic study of sleep disorders was conducted among primary school children. Those children with at least one reported biological parent were recruited. A total of 5695 children (mean age 9.2; SD 1.8), 4939 of their reported biological mothers (mean age 38.9; SD 4.6) and 4289 of their reported biological fathers (mean age 43.3; SD 5.5) were studied.
  
  
  RESULTS
  The rates of insomnia 3 times/week in the past 12 months were 4.0%, 12.8% and 9.7% for children, mothers and fathers, respectively. A robust familial aggregation of insomnia was found even after adjustment of the shared environmental and socio-demographic factors. There was a significant dose-response relationship among the children across their parental status from neither, fathers, mothers to both parents with insomnia [3.0%, 7.1%, 9.5% and 11.9%; with ORs (95% CIs)=2.48 (1.82-4.37) for fathers, 3.42 (2.55-4.59) for mothers and 4.42 (2.42-8.10) for both parents, respectively]. In addition, the frequency of insomniac symptoms of the parents also had a dose-response effect on the rate of insomnia of their children.
  
  
  CONCLUSIONS
  Insomnia is a common problem in both children and their parents. A significant familial aggregation of childhood onset insomnia was seen in this study even after adjustment of the co-risk factors. There was a dose-response effect of parental insomnia on the rate of insomnia of their children with a slight predilection of maternal influences.
authors.affiliation: Department of Psychiatry, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Jihui
authors.initials: J
authors.lastname: Zhang
authors.forename: A M
authors.initials: AM
authors.lastname: Li
authors.forename: A P S
authors.initials: AP
authors.lastname: Kong
authors.forename: K Y C
authors.initials: KY
authors.lastname: Lai
authors.forename: N L S
authors.initials: NL
authors.lastname: Tang
authors.forename: Y K
authors.initials: YK
authors.lastname: Wing
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D002648:Child; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000208:ethnology* / Q000235:genetics*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires