Table 4.

Associations between HAA z-scores and lung function and pack-years

	FVC			FEV1			FEV1/FVC			Pack-years†
	n	Expected rate of change (95% CI)	P-value	n	Expected rate of change (95% CI)	P-value	n	Expected rate of change (95% CI)	P-value	n	Expected rate of change (95% CI)	P-value
HAA z-score
Unadjusted	2740	−2.61 (−3.10, −2.13)	<0.001	2735	−2.00 (−2.55, −1.45)	<0.001	2789	0.58 (0.25, 0.90)	0.001	1425	0.06 (0.00, 0.11)	0.06
Model 1	2674	− 2.49 (− 2.96, −2.03)	<0.001	2669	−1.89 (−2.42, −1.36)	<0.001	2669	0.57 (0.25, 0.89)	<0.001	1412	0.06 (0.00, 0.11)	0.06
Model 2	2674	−2.49 (−2.95, −2.03)	<0.001	2669	−1.80 (−2.33, −1.28)	<0.001	2669	0.65 (0.33, 0.97)	<0.001	1412	0.05 (−0.01, 0.10)	0.10
Elevated
HAA
Unadjusted	2740	−8.05 (−10.91, −5.18)	<0.001	2735	−5.12 (−8.36, −1.88)	0.002	2789	2.86 (0.95, 4.77)	0.003	1425	0.18 (−0.14, 0.49)	0.28
Model 1	2674	−6.61 (−9.39, − 3.83)	<0.001	2669	−3.83 (−6.97, −0.68)	0.02	2669	2.74 (0.86, 4.61)	0.004	1412	0.15 (−0.16, 0.47)	0.34
Model 2	2674	−7.57 (−10.31, −4.84)	<0.001	2669	−5.03 (−8.13, −1.93)	0.001	2669	2.32 (0.46, 4.18)	0.01	1412	0.21 (−0.10, 0.52)	0.19

Associations are estimated by ordinary least squares regressions, P-values are calculated from two-sided t-tests and RMSE is calculated on 10-fold cross-validation. Elevated HAA is defined as the upper fifth percentile of the population (z-score ≥ 1.645). Model 1 is adjusted for study site, smoking status, pack-years, waist circumference, estimated glomerular filtration rate and educational attainment. Model 2 is adjusted for all terms included in model 1 and race, height, BMI, age and sex.

^†Analysis is conducted among current and former smokers, and models are not adjusted for smoking status or pack-years.

BMI, body mass index; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; HAA, high attenuation area; RMSE, root of mean square error.