title: [Environmental factors that influence smoking habits of monozygotic and dizygotic twins].
abstract: BACKGROUND
  Smoking habits are influenced by environmental (family, friends) and psychologic factors.
  
  
  OBJECTIVE
  To investigate environmental factors which influence the smoking habits of monozygotic and dizygotic twins.
  
  
  METHODS
  45 monozygotic and 23 dizygotic twin pairs (age 35±16 years) completed a questionnaire.
  
  
  RESULTS
  Maternal non-smoking decreases the risk of smoking of the twin children by 53%, while this effect accounts for 49% by the father. Dizygotic twins are more influenced by parents (70%) than monozygotics (31-36%). If the twin or non-twin sibling does not smoke, the risk that the twin individual starts smoking, is decreased by 86% both in monozygotic and dizygotic twins. If an individual smoking is present in the fraternity and he or she does not attempt to quit, the risk of smoking increases 8.3-fold. The role of fraternity is more important in males and youth.
  
  
  CONCLUSIONS
  The parents' and the siblings' exemplary behaviour helps to avoid smoking initiation of young twins.
authors.affiliation: Debreceni Egyetem, Népegészségügyi Kar, Komplex Rehabilitáció Msc, Debrecen. nagymona@gmail.com
authors.forename: Mónika
authors.initials: M
authors.lastname: Bakkné Nagy
authors.forename: Dávid László
authors.initials: DL
authors.lastname: Tárnoki
authors.forename: Adám Domonkos
authors.initials: AD
authors.lastname: Tárnoki
mesh_terms: D000293:Adolescent; D000328:Adult; D004781:Environmental Exposure / Q000009:adverse effects / Q000517:prevention & control / Q000706:statistics & numerical data; D005220:Fathers / Q000523:psychology / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009035:Mothers / Q000523:psychology / Q000706:statistics & numerical data; D012307:Risk Factors; D012737:Sex Factors; D035781:Siblings; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D016540:Smoking Cessation; D011795:Surveys and Questionnaires; D014429:Twins, Dizygotic / Q000523:psychology / Q000706:statistics & numerical data*; D014430:Twins, Monozygotic / Q000523:psychology / Q000706:statistics & numerical data*; D055815:Young Adult