Acute effects of smoke exposure on airway and systemic inflammation in forest firefighters

Figures & data

Table 1 Respiratory symptoms off-season and post exposure

Symptom	Off-season	Post exposure	p-value
Wheezing, n (%)	5 (9)	20 (33)	0.028
Cough, n (%)	26 (44)	43 (71)	0.03
Chest tightness, n (%)	3 (5)	11 (18)	0.02
Nocturnal symptoms, n (%)	2 (3)	4 (7)	0.578
Sneezing, n (%)	15 (25)	30 (50)	<0.001
Expectoration, n (%)	10 (16)	20 (33)	0.006

Note: Bold represents statistically significant values (p<0.05).

Table 2 Pulmonary function test and bronchial hyperresponsiveness off-season and post exposure

Functional parameter	Off-season	Post exposure	p-value
FEV1% predicted	108±13	107±16	0.796
FVC% predicted	107±14	107±12	0.760
FEF25–75% predicted	111±15	103±32	0.026
FEV1/FVC	88±8	84±4	0.024
FRC% predicted	96±20	98±18	0.637
TLC% predicted	90±11	97±11	0.029
RV% predicted	94±18	97±25	0.606
KCO% predicted	107±14	99±13	0.039
PD20meth	495±55	424±99	0.549

Notes: All values are expressed as mean ± SD, unless otherwise stated. Bold represents statistically significant values (p<0.05).

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; FEF_25–75, forced expiratory flow 25%–75%; FRC, functional residual capacity; TLC, total lung capacity; RV, residual volume; KCO, CO transfer coefficient; PD20meth, provocative dose of methacholine producing a 20% fall in FEV₁.

Table 3 Total and differential cell counts in sputum and BALF

	Off-season	Post exposure	p-value
Induced sputum
Total no. of cells × 10^4	23±4	42±6	0.624
Macrophage%	32±5	41±6	0.749
Neutrophils%	16±4	48±5	0.035
Eosinophils%	1.8±0.7	3±0.8	0.05
Lymphocytes%	13.5±2	19±6	0.637
BALF
Total no. of cells × 10^4	19±4	30±5	0.219
Macrophage%	81±2	83±3	0.629
Neutrophils%	2±0.3	4±1.2	0.043
Eosinophils%	0.58±0.13	2.4±1.2	0.05
Lymphocytes%	13±2	15±2	0.930

Notes: All values are expressed as mean ± SE, unless otherwise stated. Bold represents statistically significant values (p<0.05).

Abbreviations: BALF, bronchoalveolar lavage fluid; SE, standard error.

Figure 1 Sputum levels of TNF-α and IL-8 off-season and post exposure.

Figure 2 Serum levels of TNF-α, VEGF, and IL-8 off-season and post exposure.

Table 4 Markers of inflammation in induced sputum and serum

Marker	Off-season	Post exposure	p-value
Sputum IL-4 (pg/mL)	4 (3–38)	5 (3–47)	0.4
Sputum IL-13 (pg/mL)	188 (175–1322)	195 (178–1405)	0.3
Sputum VEGF (pg/mL)	198 (5–325)	204 (8–368)	0.83
Sputum ECP (pg/mL)	44 (4–91)	56 (6–98)	0.97
Serum IL-4 (pg/mL)	7 (6–28)	9 (6–48)	0.24
Serum IL-13 (pg/mL)	380 (307–453)	390 (327–530)	0.27
Serum ECP (pg/mL)	19 (15–45)	21 (15–118)	0.97

Note: Values are expressed as median (interquartile range).

Abbreviations: IL, interleukin; VEGF, vascular endothelial growth factor; ECP, eosinophilic cationic protein.

Figure 3 Time-dependent induction of systemic inflammation in forest firefighters with continuous exposure.