title: Genetic influences are important for most but not all lower urinary tract symptoms: a population-based survey in a cohort of adult Swedish twins.
abstract: BACKGROUND
  The relative importance of genetic and environmental factors for the occurrence of lower urinary tract symptoms (LUTS) is poorly understood.
  
  
  OBJECTIVE
  To (1) estimate the prevalence of urinary incontinence (UI), overactive bladder (OAB), and other LUTS and (2) to assess the heritability of these symptoms.
  
  
  METHODS
  Cross-sectional survey of LUTS in a national population-based cohort of Swedish twins 20-46 yr of age (n=42 582) from the Swedish Twin Registry.
  
  
  METHODS
  Prevalence rates were determined and heritability of LUTS (in female twins) was assessed using indicators of twin similarity.
  
  
  CONCLUSIONS
  A total of 25 364 twins completed the questionnaire (response rate: 59.6%). LUTS were more common in women (UI: 7%; OAB: 9%; nocturia: 61%; micturition frequency: 18%) than in men (UI: 1%; OAB: 5%; nocturia: 40%; micturition frequency: 11%), and prevalence increased with age. The strongest genetic effects were observed for UI, frequency, and nocturia. The lowest estimate for genetic effects was observed for OAB where environmental effects dominated, and more specifically shared family environment accounted for a third or more of the total variation. For stress UI, a fifth of the total variation in susceptibility to the disorder could be attributed to shared environment. Nonshared environmental effects were seen in the range of 45-65% for the various LUTS. The prevalence of LUTS was low in the men, and there were too few male cases to compute measures of similarity or heritability estimates.
  
  
  CONCLUSIONS
  This study provides robust evidence of a genetic influence for susceptibility to UI, frequency, and nocturia in women. In contrast, shared environmental factors seem more important for the predisposition to develop OAB, which may reflect familial patterns such as learning from parental behaviours.
authors.affiliation: Department of Obstetrics and Gynaecology, Sahlgrenska Academy at Gothenburg University and Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Wennberg
authors.forename: Daniel
authors.initials: D
authors.lastname: Altman
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundholm
authors.forename: Asa
authors.initials: A
authors.lastname: Klint
authors.forename: Anastasia
authors.initials: A
authors.lastname: Iliadou
authors.forename: Ralph
authors.initials: R
authors.lastname: Peeker
authors.forename: Magnus
authors.initials: M
authors.lastname: Fall
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: Ian
authors.initials: I
authors.lastname: Milsom
mesh_terms: D000328:Adult; D000367:Age Factors; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D040941:Heredity; D006801:Humans; D008297:Male; D008875:Middle Aged; D053158:Nocturia / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D010641:Phenotype; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*; D053201:Urinary Bladder, Overactive / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D014549:Urinary Incontinence / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D014554:Urination / Q000235:genetics; D055815:Young Adult