Differences in systemic inflammation between cigarette and biomass smoke-induced COPD

Figures & data

Table 1 Clinical and demographic characteristics of the studied subjects

Variable	Biomass (n=20)	Tobacco (n=20)	P-value
Males	15	15	–
Age, years	70.2±8.6	70.1±7.3	0.72
Pack-years	–	62.8±37.8	–
Hours–year	262.3±126.4	–	–
BMI, kg/m^2	31.5±5.1	29.9±5.0	0.31
Dyspnea, mMRC			0.46
0	1 (5)	1 (5)
1	7 (35)	10 (50)
2	10 (50)	9 (45)
3	2 (10)	0
4	0	0
SpO2 %	96.2±1.8	95.2±3.0	0.24
FEV1 preBD%	52.1±11.9	49.9±17.1	0.63
FVC preBD%	70.5±12.9	75.4±16.4	0.30
FEV1/FVC preBD%	54.7±9.8	48.5±12.3	0.08
FEV1 postBD%	57.6±13.6	54.4±16.4	0.52
FVC postBD%	73.8±13.2	79.5±15.3	0.20
FEV1/FVC postBD%	57.7±11.1	50.3±11.8	0.06
Positive BD test	8 (40)	6 (30)	0.96
DLCO%	84.1±21.7	67.2±22.4	0.02
DLCO/VA%	83.6±17.8	62.6±18.5	0.001
IC%	80.2±14.5	70.1±16.0	0.04
TLC%	103.1±10.6	108.1±14.1	0.22
RV%	151.5±31.7	159.1±33.6	0.47
RV/TLC%	142.6±21.6	145.5±19.6	0.67
FeNO, ppb	39.0±14.6	27.6±16.3	0.056

Note: Results are expressed as mean ± standard deviation or as number of observations (percentage).

Abbreviations: BMI, body mass index; mMRC, modified Medical Research Council; SpO₂, pulse oxygen saturation; FEV₁, forced expiratory volume in 1 s; preBD, pre-bronchodilator; FVC, forced vital capacity; postBD, post-bronchodilator; BD, bronchodilator; DLCO, carbon monoxide diffusing capacity; DLCO/VA, carbon monoxide transfer coefficient; IC, inspiratory capacity; TLC, total lung capacity; RV, residual volume; FeNO, exhaled nitric oxide.

Figure 1 Flow diagram of subject recruitment.

Abbreviations: FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity.

Table 2 Laboratory data

Variable	Biomass (n=20)	Tobacco (n=20)	Controls (n=20)	P-valuea
IL-6 (pg/mL)	1.68 (1.08–2.00)b	3.84 (2.04–7.67)b	0.00 (0.00–1.12)	<0.001
IL-8 (pg/mL)	0.71 (0.01–1.68)b	2.24 (1.32–5.34)b	0.22 (0.00–2.04)	0.005
IL-5 (pg/mL)	1.45 (1.15–1.83)c	2.08 (1.38–2.48)c	1.60 (0.99–2.20)	0.03
IL-13 (pg/mL)	23.0 (3.75–32.5)	17.5 (7.47–31.5)	13.09 (2.79–42.8)	0.99
SP (ng/mL)	7.62 (4.38–14.24)	12.53 (5.84–16.48)	5.09 (3.14–8.40)	0.054
TNF-α (pg/mL)	6.33 (3.07–8.09)	6.69 (2.45–12.43)	0.00 (0.00–0.00)	<0.001
Periostin (ng/mL)	0.42 (0.26–0.66)	0.42 (0.33–0.80)	0.00 (0.00–0.00)	<0.001
Leukocyte count (n), 10^3/mL	7.81±1.72	7.61±1.95	6.54±2.13	0.12
Neutrophil count (n), 10^3/mL	5.15 (4.00–5.60)	4.30 (3.82–5.67)	3.60 (3.00–4.02)	<0.001
Neutrophils%	62.4±8.2	61.7±6.7	56.4±9.2	0.054
Eosinophil count (n), mL	100.0 (100.0–200.0)	100.0 (100.0–200.0)	100.0 (100.0–200.0)	0.73
Eosinophils%	1.55 (1.00–2.90)	1.90 (1.12–3.25)	1.70 (1.17–2.52)	0.84
CRP	2.80 (1.50–5.86)	3.17 (2.44–8.83)	0.58 (0.13–1.01)	<0.001
ESR	7.50 (3.00–16.50)	10.00 (3.25–19.75)	3.00 (2.00–8.75)	0.14
Fibrinogen	396.0 (343.0–451.0)	387.0 (326.0–445.0)	328.0 (313.0–368.0)	0.01
Alpha-1 antitrypsin	152.5 (131.5–172.5)	132.5 (116.0–149.0)	126.0 (109.0–133.0)	<0.01
IgE	52.7 (20.3–237.5)	68.2 (15.0–212.5)	16.1 (6.9–62.8)	0.09

Notes: Results are expressed as mean ± standard deviation or as median (interquartile range).

a P-values for results of ANOVA or Kruskal–Wallis tests for comparison between biomass, tobacco and control groups.

b Comparison between biomass and tobacco groups using Mann–Whitney U test, P<0.01.

c Comparison between biomass and tobacco groups using Mann–Whitney U test, P=0.01.

Abbreviations: CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; ANOVA, analysis of variance; SP, Surfactant protein-P.

Figure 2 Differences between study groups in (A) IL-6, (B) IL-8 and (C) IL-5.

Note: The middle horizontal line represents the median, and the top and bottom horizontal lines represent 95% confidence interval for the median.
Abbreviations: T-COPD, COPD caused by tobacco; B-COPD, COPD caused by biomass smoke.