title: The clock gene PER2 and sleep problems: association with alcohol consumption among Swedish adolescents.
abstract: BACKGROUND
  Alcohol abuse is associated with sleep problems, which are often linked to circadian rhythm disturbances. Previous studies have separately examined the effects of mutations in the clock gene PER2 on alcohol consumption and sleep problems. Here we hypothesized that an allelic variation in the PER2 gene is associated with alcohol consumption in interaction with sleep problems among adolescents.
  
  
  METHODS
  The Survey of Adolescent Life and Health in Västmanland 2006, a Swedish county, including 1254 students 17-18 years old, was used as a population-representative sample of adolescents. We investigated the PER2 Single Nucleotide polymorphism (SNP) 10870 (A/G) in the cohort together with an assessment of alcohol consumption according to the AUDIT-C questionnaire, and sleep problems using a survey consisting of 18 items. Furthermore, we carried out an exploratory analysis on the PER2 Single Nucleotide Polymorphism 10870 polymorphism in a group of severely alcoholic females.
  
  
  RESULTS
  We found a significant association of the SNP 10870 in adolescent boys, where the genotype AA, in the presence of several and frequent sleep problems, was associated with increased alcohol consumption. Among adolescent girls, only sleep problems were related to alcohol consumption. A non-significant trend was observed among the severely alcoholic females, with the G allele being over-represented in the severely alcoholic females group in comparision to the control females.
  
  
  CONCLUSIONS
  These results indicate that PER2 gene variation is associated with alcohol consumption in interaction with sleep problems among Swedish adolescent boys.
authors.affiliation: Centre for Clinical Research, Uppsala University, Central Hospital, Västerås 721 89 Västerås, Sweden. erika.comasco@neuro.uu.se
authors.forename: Erika
authors.initials: E
authors.lastname: Comasco
authors.forename: Niklas
authors.initials: N
authors.lastname: Nordquist
authors.forename: Camilla
authors.initials: C
authors.lastname: Göktürk
authors.forename: Cecilia
authors.initials: C
authors.lastname: Aslund
authors.forename: Jarmila
authors.initials: J
authors.lastname: Hallman
authors.forename: Lars
authors.initials: L
authors.lastname: Oreland
authors.forename: Kent W
authors.initials: KW
authors.lastname: Nilsson
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking; D000437:Alcoholism / Q000150:complications / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D056950:Period Circadian Proteins / Q000235:genetics / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000150:complications / Q000235:genetics*; D013548:Sweden
chemical_list: C421902:PER2 protein, human; D056950:Period Circadian Proteins