title: Heritability of recurrent tonsillitis.
abstract: OBJECTIVE
  To estimate the relative contribution of genetic and environmental effects on the variance in the liability of recurrent tonsillitis.
  
  
  METHODS
  Retrospective questionnaire data from a population-based cohort.
  
  
  METHODS
  Population-based data from Norway.
  
  
  METHODS
  A total of 9479 Norwegian twins born between January 1, 1967, and December 31, 1979, identified through the Medical Birth Registry of Norway. Main Outcome Measure Recurrent tonsillitis.
  
  
  RESULTS
  The lifetime prevalence of recurrent tonsillitis was 11.7% (95% confidence interval, 11.0%-12.3%), with a significant predominance of female cases. The tetrachoric correlations for monozygotic twins were 0.71 for males and 0.60 for females. For dizygotic twins, the correlations were 0.12 for males, 0.14 for females, and 0.24 for dizygotic pairs of opposite sex. Structural equation modeling indicated that genetic effects explained 62% of the variation in the liability of recurrent tonsillitis. The remaining variance was attributed to individual environmental effects. There was no evidence of sex-specific genetic effects on the liability of recurrent tonsillitis.
  
  
  CONCLUSIONS
  There is evidence for a substantial genetic predisposition for recurrent tonsillitis.
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway. ellen.kvestad@fhi.no
authors.forename: Ellen
authors.initials: E
authors.lastname: Kvestad
authors.forename: Kari Jorunn
authors.initials: KJ
authors.lastname: Kvaerner
authors.forename: Espen
authors.initials: E
authors.lastname: Røysamb
authors.forename: Kristian
authors.initials: K
authors.lastname: Tambs
authors.forename: Jennifer Ruth
authors.initials: JR
authors.lastname: Harris
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D012008:Recurrence; D012042:Registries; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014069:Tonsillitis / Q000453:epidemiology / Q000235:genetics*