Although chronic obstructive pulmonary disease (COPD) and restrictive lung diseases are important causes of morbidity and mortality in the United States 1, 2 and 3, a large proportion of the morbidity and mortality is not pulmonary (4). This raises the possibility that lung disease may be an indicator of susceptibility to the development of other diseases or may be associated with systemic inflammation that leads to other diseases 5 and 6. Previous analyses of the relation between lung function and markers of inflammation 7 and 8 have not looked at restrictive lung disease separately.

We applied spirometric criteria to define obstructive and restrictive lung disease in adults who had pulmonary function measurements obtained as part of the Third National Health and Nutrition Examination Survey (NHANES III). We then assessed the relation of impaired lung function to circulating levels of C-reactive protein and fibrinogen, adjusting for potential covariates that may also influence these measures.