ABSTRACT
As written in the previous chapters, it is clear that exposure to cigarette
smoke, by itself, is not sufficient to explain the development of chronic obstructive pulmonary disease (COPD), and other factors including genetic
and environmental risk factors must contribute to its pathogenesis. Epide-
miological studies (family studies, twin studies, and segregation analyses)
demonstrate that COPD is a complex genetic disease, i.e., there is a genetic
component to COPD, but it is unlikely that there is a major susceptibility
gene in the majority of families.
