Reference equations for lung function screening of healthy never-smoking adults aged 18-80 years

The need for updated spirometric reference values to be used on European populations is widely acknowledged, especially for subjects aged > 70 yrs. Their reference values are generally based on extrapolations. The aim of the present study was to calculate reference values for lung function screening of healthy, never-smoking adults aged 18-80 yrs and to compare them with the most widely used reference equations. Results of screening spirometry of 8,684 healthy, never-smoking adults were used to calculate mean values and fifth percentiles of lung function variables. The European Community of Coal and Steel (ECCS) reference equations underestimate forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). For example, in 50-yr-old males (height 175 cm), lower limits of normal for FEV1 are underestimated by 198 mL, and for FVC by 210 mL. In 50-yr-old females (height 165 cm), lower limits of normal for FEV1 are underestimated by 191 mL, and for FVC by 270 mL. The decline of FVC in elderly subjects is steeper than predicted by the ECCS. Reference equations derived from spirometry data locally collected in a practical setting by well-trained personnel might be more appropriate for everyday use than generally used equations based on data from scientific studies in the distant past.