A team from the University of British Columbia in Vancouver examined 143 men and women taking part in cancer screening trials. Researchers measured participants' percentage over-inflated lung area using CT scans.
They found this percentage predicted annual decline in FEV1 in smokers with a normal baseline FEV1. They suggest that overinflated lungs contain the earliest forms of lesions that initiate lung tissue destruction.
They concluded: 'Quantitative assessment... on initial CT scans may identify the "susceptible minority of smokers" who eventually will develop COPD.'