NEW YORK, June 20 (Praxis Press) Obstructive lung disease (OLD) is an important cause of morbidity and mortality, but potentially treatable mild cases of OLD may often go undetected. To determine the national estimates of reported OLD and low lung function in the US adult population Mannino and colleagues examined data from the Third National Health and Nutrition Examination Survey (NHANES III) surveying 20,050 participants(see paper). Overall a mean of 6.8% of the population had low lung function, and 8.5% of the population reported OLD. Obstructive lung disease is present in a substantive number of US adults and many US adults have low lung function but no reported OLD diagnosis, which may indicate the presence of undiagnosed lung disease.