title: Familial transmission of chronic obstructive pulmonary disease in adoptees: a Swedish nationwide family study.
abstract: OBJECTIVE
  Familial clustering of chronic obstructive pulmonary disease (COPD) is well established, but the familial risk of COPD has not been determined among adoptees. The aim was to determine whether the familial transmission of COPD is related to disease in biological and/or adoptive parents.
  
  
  METHODS
  Historic cohort study.
  
  
  METHODS
  80,214 (50% females).
  
  
  METHODS
  The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born in 1932-2004 (n=80,214) between 1 January 1964 and 31 December 2010 for COPD (n=1978). The risk of COPD was estimated in adoptees with at least one biological parent with COPD but no adoptive parent with COPD (n=162) compared with adoptees without a biological or adoptive parent with COPD. The risk of COPD was also determined in adoptees with at least one adoptive parent but no biological parent with COPD (n=110), and in adoptees with both affected biological and adoptive parents (n=162).
  
  
  METHODS
  COPD in adoptees.
  
  
  RESULTS
  Adoptees with COPD in at least one biological parent but no adoptive parent were more likely to have COPD than adoptees without a biological or adoptive parent with COPD (standardised incidence ratio, SIR=1.98 (95% CI 1.69 to 2.31)). The familial SIR for adoptees with both a biological parent and an adoptive parent with COPD was 1.68 (95% CI 1.39 to 2.00). Adoptees with at least one adoptive parent with COPD but no biological parent with COPD were not at an increased risk of COPD (SIR=1.12 (95% CI 0.92 to 1.35)).
  
  
  CONCLUSIONS
  The findings of the study show that the familial transmission of COPD is associated with COPD in biological but not adoptive parents, suggesting that genetic or early life factors are important in the familial transmission of COPD.
authors: Center for Primary Health Care Research, Lund University, Malmö, Sweden.
authors: Bengt
authors: B
authors: Zöller
authors: Center for Primary Health Care Research, Lund University, Malmö, Sweden.
authors: Xinjun
authors: X
authors: Li
authors: Center for Primary Health Care Research, Lund University, Malmö, Sweden Stanford Prevention Research Centre, Stanford University School of Medicine, Stanford, California, USA.
authors: Jan
authors: J
authors: Sundquist
authors: Center for Primary Health Care Research, Lund University, Malmö, Sweden Stanford Prevention Research Centre, Stanford University School of Medicine, Stanford, California, USA.
authors: Kristina
authors: K
authors: Sundquist
mesh_terms: D000300:Adoption; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010290:Parents; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000235:genetics*; D012042:Registries; D012307:Risk Factors; D012931:Social Environment; D013548:Sweden / Q000453:epidemiology
keywords: EPIDEMIOLOGY; GENETICS; RESPIRATORY MEDICINE (see Thoracic Medicine)