title: High heritability for concurrent low back and neck-shoulder pain: a study of twins.
abstract: METHODS
  A cross-sectional study on 21,225 twins based on a Web-based questionnaire was performed in 2005-2006 and administered by the Swedish Twin Registry.
  
  
  OBJECTIVE
  To investigate the importance of genetic factors for the occurrence of "Concurrent low back (LBP) and neck-shoulder pain (NSP)" as well as of "Solely LBP," and "Solely NSP" in an adult population of women and men.
  
  
  BACKGROUND
  Many individuals suffering from LBP also have concurrent NSP, and little is known about the factors influencing the occurrence of this spinal comorbidity.
  
  
  METHODS
  Heritability of Concurrent LBP and NSP, solely LBP, and solely NSP was analyzed in 2934 monozygotic twin pairs, 2009 same-sex dizygotic (DZ) twin pairs, and 1960 opposite-sex DZ twin pairs without any known rheumatic disorders using structural equation modeling (SEM).
  
  
  RESULTS
  The SEM showed that 60% of the total variance for concurrent LBP and NSP can be explained by additive genetic effects, which was twice as large as for solely LBP (30%) and more than twice as large as for solely NSP (24%).
  
  
  CONCLUSIONS
  Genetic factors had a considerably greater importance for the occurrence of concurrent LBP and NSP compared with solely LBP or solely NSP. The influence of genetic factors was similar for solely LBP and solely NSP.
authors.affiliation: Department of Public Health Sciences, Division of Occupational and Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. teresia.nyman@ki.se
authors.forename: Teresia
authors.initials: T
authors.lastname: Nyman
authors.forename: Marie
authors.initials: M
authors.lastname: Mulder
authors.forename: Anastasia
authors.initials: A
authors.lastname: Iliadou
authors.forename: Magnus
authors.initials: M
authors.lastname: Svartengren
authors.forename: Christina
authors.initials: C
authors.lastname: Wiktorin
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D020022:Genetic Predisposition to Disease; D006304:Health Status; D040941:Heredity; D006801:Humans; D020407:Internet; D017116:Low Back Pain / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D010147:Pain Measurement; D010375:Pedigree; D010641:Phenotype; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D020069:Shoulder Pain / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*; D055815:Young Adult