FIGURE 4.
Change in spirometry with strata of lung volumes. Development of COPD and change in forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and their ratio across strata of a) functional residual capacity (FRC)/total lung capacity (TLC), b) FRC and c) TLC at 5-year follow-up visit. Coefficients (95% CI) from regression models of spirometric indices versus tertiles of lung volumes are shown. #: models of spirometry versus lung volumes that were statistically significant in linear modelling in addition to the categorical models.