Normal values of spirometry for the 15- to 20-year-old age group

In 130 healthy young men and women aged 15 to 20 years, all non-smokers, volume flow curves were recorded during forced expiratory vital capacity measurements. The forced vital capacity (FVC), the forced expiratory volume of 1 sec (FEV1) and the mid-expiratory flow rate (MEF50) were evaluated in order to establish new standard values for normal people in this particular age group. FVC is strongly height and sex dependent. Our new normal values are in good agreement with those of the literature. Our FVC values, however, are in general slightly higher than those of previous authors. MEF50 turns out to be sex independent but height dependent, but not as much as FVC. Our new normal values for MEF50 are in good agreement with those of Knudson et al., though slightly lower. The FEV1/FVC quotient was found to decrease significantly with height from 0.9 to 0.8. This decrease may be due to the increase in lung volume with growth. It could also be due to lung damage caused by atmospheric air pollution in young adults who are still growing.