Hersh et al analyzed spirometry and patient-reported data on family history from the COPDGene study, comparing 821 people with COPD to 776 smoking controls. Subject-recalled parental history of COPD had an odds ratio of 1.7 for COPD in the subject. The population attributable risk from family history for COPD was 18.6%.
They acknowledge the vulnerability of these findings to recall bias -- if you have COPD, wouldn't you be more likely to recall it in or attribute it to your mom & dad? CHEST 2011;140:331-342.