title: Modest genetic influence on bronchodilator response: a study in healthy twins.
abstract: OBJECTIVE
  To determine the reasons for large standard deviation of bronchodilator response (BDR) and establish whether there is a potential heritable component in healthy subjects.
  
  
  METHODS
  67 monozygotic and 42 dizygotic adult twin pairs were assessed for bronchodilator response (% change in FEV1 after inhaling 400 µg salbutamol). Univariate quantitative genetic modeling was performed.
  
  
  RESULTS
  Multiple regression modeling showed a significant association between BDR and sex and baseline FEV1 (P<0.05), while no association was found with smoking habits, body mass index, or age. Within pair correlation in monozygotic twins was modest (0.332), but higher than in dizygotic twins (0.258). Age-, sex-, and baseline FEV1-adjusted genetic effect accounted for 14.9% (95% confidence interval, CI 0%-53.1%) of the variance of BDR, shared environmental effect for 18.4% (95% CI 0%-46.8%), and unshared environmental effect for 66.8% (95% CI 46.8%-88.7%).
  
  
  CONCLUSIONS
  Our twin study showed that individual differences in BDR can be mostly explained by unshared environmental effects. In addition, it is the first study to show low, insignificant hereditary influences, independently from sex, age, and baseline FEV1.
authors.affiliation: David Laszlo Tarnoki, Department of Radiology and Oncotherapy, Semmelweis University, 78/A Ulloi street, 1082 Budapest, Hungary, tarnoki4@gmail.com.
authors.forename: David Laszlo
authors.initials: DL
authors.lastname: Tarnoki
authors.forename: Emanuela
authors.initials: E
authors.lastname: Medda
authors.forename: Adam Domonkos
authors.initials: AD
authors.lastname: Tarnoki
authors.forename: Andras
authors.initials: A
authors.lastname: Bikov
authors.forename: Zsofia
authors.initials: Z
authors.lastname: Lazar
authors.forename: Corrado
authors.initials: C
authors.lastname: Fagnani
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Stazi
authors.forename: Kinga
authors.initials: K
authors.lastname: Karlinger
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Garami
authors.forename: Viktor
authors.initials: V
authors.lastname: Berczi
authors.forename: Ildiko
authors.initials: I
authors.lastname: Horvath
mesh_terms: D000328:Adult; D000420:Albuterol / Q000008:administration & dosage*; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D005260:Female; D005541:Forced Expiratory Volume / Q000235:genetics*; D059647:Gene-Environment Interaction; D006801:Humans; D008297:Male; D008875:Middle Aged; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol