The diagnosis of chronic obstructive pulmonary disease (COPD) relies on demonstration of airflow obstruction on spirometry. Traditional spirometric indices miss a number of subjects with respiratory symptoms. We recently described three novel ways to detect airflow obstruction with which we were able to detect an additional 9.5% participants who did not have airflow obstruction using traditional thresholds. These individuals had worse shortness of breath and poorer quality of life compared to controls who were normal by all criteria. They also had evidence of structural lung disease on CT with more emphysema and gas trapping than controls. In this proposal, we aim to define normal values for the three new spirometry measures and to test whether the new spirometry measures can identify more symptomatic individuals compared with traditional spirometry criteria. We will analyse the raw datapoints of each spirometry curve to define these new parameters. We will then derive normal values in the population using data from lifetime nonsmokers and those without symptoms and then test whether we can detect abnormalities in individuals with and without symptoms, compared with traditional spirometry criteria. We anticipate completing this project within 36 months of receipt of data. Our results will help define normal values for these new spirometry measures that will help identify early/mild airflow obstruction.
