Lung function and CT lung densitometry in 37- to 39-year-old individuals with alpha-1-antitrypsin deficiency

Figures & data

Table 1 Clinical characteristics of the study participants

Pi phenotype	PiZZ (n=41)	PiSZ (n=18)	PiMM (n=61)
Gender: men, n (%)	21 (51%)	11 (61%)	22 (36%)
Age (years), mean (range)	38.4 (37.0–39.0)	38.3 (38.0–39.0)	38.0 (37.0–39.0)
BMI,a mean (range)	25 (19–42)	27 (22–32)	26 (19–38)
Smoking habits
Never, n (%)	30 (73%)	16 (89%)	43 (71%)
Former, n (%)	9 (22%)	2 (11%)	10 (16%)
Current, n (%)	2 (5%)	0	8 (13%)
Pack-years, ever-smokers mean (range)	9.2 (2.3–20)	1.9 (0.3–3.5)	11.8 (1.0–25.0)

Note:

a BMI (body mass index) = weight (kg)/height² (m).

Abbreviation: Pi, protease inhibitor.

Table 2 Results of the pulmonary function tests (PFT), diffusing capacity, and impulse oscillometry (IOS) in the Pi subgroups

Pi phenotype	PiZZ (n=41) Mean (95% CI)	PiSZ (n=18) Mean (95% CI)	PiMM (n=61) Mean (95% CI)
PFT
FEV1 % pred.	104 (99–106)	104 (98–110)	108 (105–111)
VC % pred.	116 (112–120)	114 (107–121)	117 (114–120)
FEV1/VC ratio	76 (72–79)	77 (74–80)	78 (77–80)
FEV1/VC % pred.	94 (90–98)	95 (92–99)	96 (95–98)
TLC % pred.	114 (109–118)	109 (102–116)	110 (108–113)
RV % pred.	118 (109–126)a	107 (98–117)	103 (100–106)
RV/TLC ratio	30 (28–31)b	28 (26–30)	28 (27–28)
RV/TLC % pred.	93 (88–97)c	87 (82–92)	87 (84–89)
FRC % of pred.	130 (117–143)	116 (101–131)	117 (110–123)
FRC/TLC ratio	49 (47–50)d	44 (40–48)	46 (44–48)
FRC/TLC % pred.	75 (68–83)	65 (51–78)	76 (70–83)
Diffusing capacity
DL,CO % pred.	92 (88–96)	98 (91–106)	95 (93–98)
Kco % pred.	92 (88–96)e	102 (95–109)	97 (94–100)
Impulse oscillometry
R5Hz kPa (L/s)	0.26 (0.25–0.28)f	0.28 (0.25–0.31)	0.30 (0.29–0.32)
R20Hz kPa (L/s)	0.25 (0.23–0.26)g	0.26 (0.23–0.28)	0.28 (0.27–0.30)
R5Hz–R20Hz kPa (L/s)	0.017 (0.01–0.03)	0.02 (0.01–0.04)	0.02 (0.01–0.03)
X5Hz kPa (L/s)	−0.06 (−0.07 to −0.05)h	−0.07 (−0.08 to −0.05)	−0.08 (−0.09 to −0.07)
Fres Hz	8.8 (8.1–9.5)	8.7 (7.2–10.1)	9.4 (8.8–10.0)
Alx kPa/L	0.13 (0.09–0.17)i	0.15 (0.09–0.20)	0.21 (0.16–0.25)

Notes:

a P<0.01 vs PiMM;

b P<0.05 vs PiMM;

c P<0.05 vs PiMM;

d P<0.05 vs PiSZ;

e P<0.01 vs PiSZ;

f P<0.01 vs PiMM;

g P<0.01 vs PiMM;

h P<0.05 vs PiMM;

i P<0.05 vs PiMM.

Abbreviations: Alx, area of low reactance; D_L,CO, diffusing capacity for carbon monoxide; FEV₁, forced expiratory volume in 1 second; FRC, functional residual capacity; Fres, resonant frequency; Kco, carbon monoxide transfer coefficient; Pi, protease inhibitor; R5Hz, respiratory system resistance at 5 Hz; R20Hz, respiratory system resistance at 20 Hz; RV, residual volume; TLC, total lung capacity; VC, vital capacity; X5Hz, respiratory system reactance at 5 Hz.

Table 3 Results of the pulmonary function tests (PFT) and diffusing capacity in the ever- and never-smoking Pi subgroups

Pi phenotype	PiZZ		PiSZ	PiMM
Smoking groups	Never-smokers (n=30) Mean (95% CI)	Ever-smokers (n=11) Mean (95% CI)	Never-smokers (n=16) Mean (95% CI)	Never-smokers (n=43) Mean (95% CI)	Ever-smokers (n=18) Mean (95% CI)
PFT
FEV1 % pred.	106 (101–110)	99 (83–115)	102 (96–109)	108 (105–112)	107 (100–113)
VC % pred.	113 (109–118)	122 (113–130)	112 (105–119)	116 (113–120)	118 (111–125)
FEV1/VC % pred.	97 (94–99)	85 (72–98)	95 (91–98)	97 (95–99)	95 (91–99)
FEV1/VC ratio	78 (76–81)	69 (59–80)	77 (74–80)	79 (78–80)	77 (74–81)
TLC % pred.	110 (106–114)	123 (112–134)a	108 (101–115)	109 (106–112)	113 (107–118)
RV % pred.	112 (106–118)	133 (103–163)b	107 (96–117)	101 (97–105)	107 (101–113)
RV/TLC ratio	29 (28–30)	32 (27–37)c	28 (26–30)	27 (26–28)	28 (27–30)
RV/TLC % pred.	90 (86–94)	99 (82–116)d	87 (81–93)	86 (83–89)	89 (84–94)
FRC % pred.	121 (112–130)	154 (111–198)e	112 (97–128)	118 (110–126)	113 (102–124)
FRC/TLC ratio	48 (46–50)	51 (48–55)f	43 (38–47)	46 (43–48)	46 (42–50)
FRC/TLC % pred.	70 (62–79)	89 (73–105)g	61 (47–75)	76 (68–84)	78 (65–91)
Diffusing capacity
DL,CO % pred.	93 (89–97)	89 (78–100)	98 (90–105)	96 (93–99)	93 (87–99)
Kco % pred.	94 (91–98)	85 (73–96)h	103 (95–111)	99 (96–103)	92 (86–97)

Notes:

a P<0.05 vs PiZZ never-smokers, P<0.01 vs PiSZ never-smokers, P=0.01 vs PiMM never-smokers;

b P<0.01 vs PiMM never-smokers;

c P=0.01 vs PiMM never-smokers;

d P=0.01 vs PiMM never-smokers;

e P=0.01 vs PiMM ever-smokers, P=0.01 vs PiMM never-smokers, P<0.05 vs PiZZ never-smokers, P=0.01 vs PiSZ never-smokers;

f P<0.05 vs PiSZ never-smokers;

g P<0.05 vs PiSZ never-smokers;

h P<0.01 vs PiMM never-smokers, P<0.01 vs PiSZ never-smokers.

Abbreviations: D_L,CO, diffusing capacity for carbon monoxide; FEV₁, forced expiratory volume in 1 second; FRC, functional residual capacity; Kco, carbon monoxide transfer coefficient; Pi, protease inhibitor; RV, residual volume; TLC, total lung capacity; VC, vital capacity.

Figure 1 The RV % predicted in Pi-smoking categories.

Note: The means are indicated by horizontal bars.

Abbreviations: Pi, protease inhibitor; RV, residual volume.

Figure 2 The Kco % predicted in the Pi-smoking categories.

Note: The means are indicated by horizontal bars.
Abbreviations: Pi, protease inhibitor; Kco, carbon monoxide transfer coefficient.

Table 4 Results of computed tomography (CT) densitometry in the Pi subgroups, independent of smoking categories

Pi phenotype	PiZZ (n=41) Mean (95% CI)	PiSZ (n=15) Mean (95% CI)	PiMM (n=48) Mean (95% CI)
Heterogeneity	5.1 (3.6–6.7)	3.2 (2.4–4.0)	3.4 (3.0–3.8)
Whole RA−910	27 (21–33)	30 (22–32)	23 (19–28)
Whole PD15 (g/L)	82 (75–89)	79 (70–88)	89 (82–95)
Apical RA−910	78 (71–86)	77 (67–87)	86 (80–93)
Apical PD15 (g/L)	31 (25–38)	34 (24–44)	26 (21–31)
Basal RA−910	25 (19–31)	29 (21–37)	23 (18–29)
Basal PD15 (g/L)	85 (78–92)	80 (72–88)	89 (83–96)

Abbreviations: PD₁₅, 15th percentile density; Pi, protease inhibitor; RA₋₉₁₀, relative area below -910 HU.

Table 5 Results of the computed tomography (CT) densitometry in ever- and never-smoking Pi subgroups. Means and 95% CI are shown

Pi phenotype	PiZZ		PiSZ	PiMM
	Never-smokers (n=30) Mean (95% CI)	Ever-smokers (n=11) Mean (95% CI)	Never-smokers (n=15) Mean (95% CI)	Never-smokers (n=32) Mean (95% CI)	Ever-smokers (n=16) Mean (95% CI)
Heterogeneity	4.1 (3.3–4.8)	8.0 (2.1–13.8)	3.2 (2.4–4.0)	3.5 (2.9–4.1)	3.3 (2.8–3.7)
Whole RA−910	25 (19–31)	33 (18–47)	30 (22–38)	25 (18–31)	21 (13–28)
Whole PD15 (g/L)	83 (77–90)	78 (57–99)	79 (70–88)	87 (79–95)	92 (79–105)
Apical RA−910	30 (21–35)	41 (22–59)	34 (24–44)	27 (21–34)	24 (15–32)
Apical PD15 (g/L)	81 (74–87)	72 (49–95)	77 (67–87)	85 (77–92)	90 (77–103)
Basal RA−910	24 (18–31)	27 (13–41)	29 (21–37)	25 (18–32)	21 (13–28)
Basal PD15 (g/L)	84 (77–91)	88 (68–108)	80 (72–88)	88 (80–96)	92 (80–105)

Abbreviations: PD₁₅, 15th percentile density; Pi, protease inhibitor; RA₋₉₁₀, relative area below -910 HU.

Table 6 Results of the pulmonary function tests (PFT), diffusing capacity, impulse oscillometry (IOS), and computed tomography (CT) densitometry in the only two PiZZ current smokers, both female

Pi phenotype	PiZZ Current smoker 1	PiZZ Current smoker 2
Age (years)	39	37
Smoking, pack-years (n)	12	8
FEV1 % pred.	64	51
VC % pred.	109	123
FEV1/VC ratio	51	36
FEV1/VC % pred.	62	44
TLC % pred.	152	142
RV % pred.	245	180
RV/TLC ratio	50	39
RV/TLC % pred.	156	125
FRC % pred.	340	157
FRC/TLC ratio	55	52
FRC/TLC % pred.	107	102
DL,CO % pred.	72	57
Kco % pred.	66	50
R5Hz kPa (L/s)	0.30	0.37
R20Hz kPa (L/s)	0.24	0.29
R5Hz–R20Hz kPa (L/s)	0.06	0.08
X5Hz kPa (L/s)	−0.10	−0.12
Fres Hz	11.8	16.3
Alx kPa/L	0.27	0.55
Heterogeneity	8.6	26.8
Whole RA−910	61.2	33.1
Whole PD15 (g/L)	44	64

Abbreviations: Alx, area of low reactance; D_L,CO, diffusing capacity for carbon monoxide; FEV₁, forced expiratory volume in 1 second; FRC, functional residual capacity; Fres, resonant frequency; Kco, carbon monoxide transfer coefficient; PD₁₅, 15th percentile density; Pi, protease inhibitor; RA₋₉₁₀, relative area below -910 HU; R5Hz, respiratory system resistance at 5 Hz; R20Hz, respiratory system resistance at 20 Hz; RV, residual volume; TLC, total lung capacity; VC, vital capacity; X5Hz, respiratory system reactance at 5 Hz.

Figure S1 Cohort and control group questionnaire.

Notes: A Swedish version of this questionnaire was used for 26, 30, and 34-year follow-ups and the current follow-up, and was translated (by a professional translator) to English at the 30-year follow-up. At that follow-up we removed a question and added two new ones.

StollerJKAboussouanLSA review of α1-antitrypsin deficiencyAm J Respir Crit Care Med2012185324625921960536

 PubMed Web of Science ®Google Scholar