A motivational tool for smoking intervention by healthcare professionals Smoking is attributed as the main cause of COPD (Chronic Obstructive Pulmonary Disease). COPD is often undiagnosed and untreated in its early stages, especially in smokers. A key indicator of COPD is a reduced FEV1 compared with predicted FEV1 value. Early identification of a reduction in FEV1 can provide early warning of the damage already suffered by the lungs at the pre-symptomatic stage, when smoking cessation is most effective. The Vitalograph lung age compares a subject's FEV1 with predicted normal values to calculate the subject's 'lung age'. A high lung age in relation to the subject's chronological age can illustrate the likely negative impact of continued smoking on lung function and encourage smoking cessation.