Age-related decline in forced expiratory volume in one second (FEV1)% predicted plotted as % of maximal at age 20 years against age.
Note: Adapted from Ware JH, Dockery DW, Louis TA, et al. 1990. Longitudinal and cross-sectional estimates of pulmonary function decline in never-smoking adults. Am J Epidemiol, 132:685-700. Copyright © 2004. Reprinted with permission from Oxford University Press.