Table 4:

Longitudinal Change in Volume-adjusted Lung Density, Stratified according to Presence or Absence of COPD and according to Presence or Absence of Parenchymal and Paraseptal Emphysema

	COPD (n = 1655)		No COPD (n = 2511)
Presence or Absence of Emphysema	Mean Change (g/L)	P Value	Mean Change (g/L)	P Value
Parenchymal emphysema
No emphysema at baseline	−0.1 (−1.4, 1.3)	.92	−0.2 (−0.9, 0.6)	.64
Emphysema at baseline	−5.1 (−6.0, −4.1)	<.001	−2.6 (−3.4, −1.8)	<.001
Paraseptal emphysema
No paraseptal emphysema at baseline	−3.0 (−4.0, −2.1)	<.001	−0.9 (−1.6, −0.3)	.005
Paraseptal emphysema at baseline	−6.0 (−7.1, −4.8)	<.001	−3.5 (−4.7, −2.3)	<.001

Note.—Models are adjusted for age, height, sex, race, and smoking status. Progressions differed by extent of emphysema (P < .001) for each group (COPD or no COPD) and emphysema classification variable. Numbers in parentheses are 95% CIs. COPD = chronic obstructive pulmonary disease.