Lung Features in Individuals with Biomass Smoke Exposure Characterized by CT Scan and Changes in Pulmonary Function

Figures & data

Figure 1 Flow chart of the study participants.

Abbreviations: CT, computed tomography; CSE, cigarette smoke exposure; BSE, biomass smoke exposure; COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Figure 2 Sample computed tomography (CT) scans used to determine pulmonary small vessels. (A) CT image in middle slice of lung. (B) Segmented lungs shaded in grey. (C) Pulmonary vessels shaded in green. (D) Pulmonary small vessels shaded in red.

Figure 3 Sample computed tomography (CT) scans used to determine pectoralis muscle, erector spinae muscle. (A) Pectoralis major muscle shaded in red, pectoralis minor muscle shaded in brown. (B) Erector spinae muscle shaded in red.

Table 1 Baseline Characteristics Among BSE, CSE Groups and Healthy Control Groups

	BSE Groups		CSE Groups		Healthy Control	P
	BSE Normal	BSE+ COPD	CSE Normal	CSE+ COPD
	n=16	n=19	n=13	n=25	n=25
Sex						<0.01^a
Male	2	1	13	25	16
Female	14	18	0	0	9
Age, years	59 (57–66)	67 (57–72)	63 (59–67)	65 (60–70)	61 (58–70)	0.19^a
BMI, kg/m^Citation2	22.38±3.27	23.78±5.39	23.68±3.34	21.6±3.67	24.2±3.69	0.14^a
FVC%	101.3 (95.0–111.4)	124.5 (113.1–136.0)	102.9 (102.5–111.8)	106.0 (103.3–112.9)	99.6 (94.3–105.0)	0.03^a
FEV1%	95.0 (87.8–100.0)	100.5 (87.9–113.1)^†	96.8 (93.6–102.5)	87.7 (80.1–89.7)*^†	83.8 (82.3, 94.9)	<0.01^a
FEV1/FVC	84.0 (76.1–86.2)	66.2 (63.5–68.8)*^†	77.4 (75.8–82.9)	63.8 (60.5–66.5)*^†	94.2 (87.6–95.1)	<0.01^a
GOLD stage, n
I	NA	13	NA	14	NA	0.45^b
II	NA	6	NA	11	NA
BSE index (hours-years)	51 (37.5,82)	40 (20,60)	0 (0,0)	0 (0,0)	0 (0,0)	0.38^c
Cigarette smoking index (pack-years)	0 (0,0)	0 (0,0)	39 (20,76)	40 (27.5, 54)	0 (0,0)	0.52^d
Declined FEV1 (mL/year)	5.1 (−10.0 to 45.5)	21.4 (0 to 42.7)^§	40.0 (28.5 to 56.8)	69.5 (39.8 to 113.5)	NA	<0.01^b
Declined FVC (mL/year)	27.9 (−50.8 to 58.3)	38.7 (2.75 to 88.8)	31.1 (17.8 to 54.9)	62.9 (32.1 to 112.2)	NA	0.48^b
Declined FEV1/FVC (%/year)	0.19 (−0.52 to 1.28)	−0.32 (−1.1 to 0.47)^§	0.79 (0.45 to 1.08)	0.89 (−0.2 to 1.56)	NA	0.03^b

Notes: Values were given as mean ± SD or median (quartile). ^aComparison among five groups. ^bComparison between BSE+COPD group and CSE+COPD group. ^cComparison between BSE normal group and BSE+COPD group. ^dComparison between CSE normal group and CSE+COPD group. *Compared between same subgroup, P<0.05. ^†Compared with healthy control group, P<0.05. ^§Compared with CSE+COPD group, P<0.05.

Abbreviations: BSE, biomass smoke exposure; CSE, cigarette smoke exposure; FEV_1, forced expiratory volume in one second; FVC, forced vital capacity; NA, not applicable.

Table 2 Comparison of CT Characteristics on Emphysema, Pulmonary Small Vessel and Airway Remodeling Among BSE, CSE Groups and Healthy Groups

	BSE Groups		CSE Groups		Healthy Control	P^a
	BSE Normal	BSE+COPD	CSE Normal	CSE+ COPD
	n=16	n=19	n=13	n=25	n=25
LAA-950 (%)	4.17 (0.53–5.60)	7.84 (5.17–11.36)^†*	3.17 (1.52–6.00)	12.61 (5.79–17.36)*^†	1.96 (1.23–3.4.)	<0.01
(Upper third)/(lower third) ratio of LAA-950	0.96 (0.37–1.27)^†	0.73 (0.54–0.9)^§†	1.00 (0.67–1.73)	1.17 (0.72–1.75)	0.68 (0.65–1.04)	0.01
%CSA<5	1.05 (0.84–1.45)^†	0.86 (0.65–0.98)^†	0.93 (0.91–0.99)^†	1.10 (0.66–1.32)^†	1.80 (1.27–2.14)	<0.01
RB1 Third
IR (mm)	3.47±0.94	3.24±0.81^†§	3.71±0.75	4.2±0.87	3.85±1.12	0.02
WA%	71.57±7.72^†	71.98±7.22^†§	65.15±7.1	66.04±7.58	61.81±8.73	<0.01
RB1 Fourth
IR (mm)	2.11 (1.86–2.41)	2.09 (1.76–2.52)	2.48 (2.39–2.8)	2.42 (2.08–2.7)	2.47 (1.97–2.95)	0.06
WA%	78.11 (74.17–80.64)^†	77.12 (75.07–81.6)^†§	75.00 (68.03–77.25)	72.05 (69.87–76.27)	69.8 (66.16–72.98)	<0.01
RB1 Fifth
IR (mm)	1.65±0.38^†	1.66±0.5^†§	1.99±0.46	2.01±0.39	1.95±0.48	0.05
WA%	82.76±5.82^†	80.85±4.56^†	78.39±5.43^†	78.21±4.85^†	72.26±6.74	<0.01
RB1 Sixth
IR (mm)	1.27 (0.88–1.6)^†	1.16 (0.88–1.40)^†§	1.53 (1.28–1.58)	1.44 (1.24–1.64)	1.47 (1.33–1.80)	0.01
WA%	84.29 (80.92–90.88)^†	87.73 (85.57,90.88)^†§	82.44 (82.02–88.65)^†	82.24 (75.98–86.44)^†	76.86 (71.72–79.03)	<0.01
RB10 Third
IR (mm)	3.25±0.71	3.07±0.73^†§	3.95±0.59	3.63±0.58	3.58±0.62	0.02
WA%	70.82±6.81^†	71.79±6.77^†	65.21±5.69^†	67.56±6.08^†	62.44±5.2	<0.01
RB10 Fourth
IR (mm)	2.60 (1.85–3.08)^†‡	1.98 (1.81–2.54)^†§	3.34 (2.33–4.14)	2.99 (2.51–3.82)	2.91 (2.41–3.6)	0.03
WA%	74.03 (68.08–83.46)^†	76.55 (70.18–80.51)^†	65.44 (58.76–73.49)	72.58 (65.72–77.21)^†	65.15 (60.71–71.44)	<0.01
RB10 Fifth
IR (mm)	1.84 (1.49–2.53)^†‡	1.37 (1.24–2.6)^§†	2.88 (2.4–2.98)	2.40 (1.85–3)	2.31 (2.12–2.81)	<0.01
WA%	78.11 (71.02–81.63)^†	82 (74.61–86.97)^†§	73.98 (69.65–76.07)	77.40 (72.86–81.78)^†	68.46 (65.44–72.6)	<0.01
RB10 Sixth
IR (mm)	1.60 (1.15–1.99)^†	1.11 (1–1.55)^†§	1.86 (1.69–2.48)	1.82 (1.51–2.25)	2.12 (1.7–2.41)	<0.01
WA%	83.72 (79.38–87.45)^†	87.53 (84.35–87.53)^†§	81.56 (74.32–82.87)	80.45 (75.89–84.26)^†	74.07 (72.23–77.96)	<0.01

Notes: Values were given as mean ± SD or median (quartile). ^aComparison among five groups. *Compared between same subgroup, P<0.05. ^†Compared with healthy control group, P<0.05. ^‡Compared with CSE normal group, P<0.05. ^§Compared with CSE+COPD group, P<0.05.

Abbreviations: %LAA−950, CT measurement of the percentage of low attenuation area less than −950 Hounsfield units, defined as emphysema; %CSA_<5, percentage of total lung area taken up by the cross-sectional area of pulmonary vessels less than 5 mm²; IR, inner radius; RB1, upper lobe apical bronchus; RB10, right lower lobe posterior bronchus. WA%, percentage of wall.

Table 3 Comparison of CT Characteristics on Pectoralis Muscle and Erector Spinae Muscle Among BSE, CSE Groups and Healthy Groups

	BSE Groups		CSE Groups		Healthy Control	P^a
	BSE Normal	BSE+COPD	CSE Normal	CSE+ COPD
	n=16	n=19	n=13	n=25	n=25
Area of left P. major muscle (mm^2)	1014.93 (950.8–1161.92)^†	764.82 (723.05–898.51)*^§	1201.07 (1177–1341.21)^†	1129.86 (861.27–1439.53)^†	849.24 (734.08–1141.36)	<0.01
Area of left P. minor muscle (mm^2)	386.03 (352.46–480.31)	392.58 (314.06–500.72)	426.79 (411.29–475.16)	471.3 (413.72–529.19)	441.13 (297.32–478.03)	0.29
Area of ESM (mm^2)	2534.81 (2324.09–2628.93)	2085 (1993.57–2331.64)^§	2922.02 (2697.74–3105.15)^†	2699.14 (2244.37–3075.55)^†	2209.28 (1755.69–2640.51)	<0.01
Area of right P. major muscle (mm^2)	1139.53 (1040.66–1279.96)^†	742.69 (690.03–975.68)^§	1428.62 (1134.52–1495.97)^†	1097.76 (922.13–1363.39)	981.03 (750.67–1107.26)	0.01
Area of right P. minor muscle (mm^2)	403.63 (333.17–512.48)	348.71 (319.33–452.86)^§	524.15 (458.29–553.31)^†	467.67 (392.29–580.31)^†	381.59 (282.52–438.78)	<0.01
Density of left P. major muscle (HU)	43.41 (39.34–47.11)^‡	46.57 (37.38–53.8)^§	53.1 (50.94–58.74)^†	54.18 (48.4–59.34)^†	40.66 (34.74–46.22)	<0.01
Density of left P. minor muscle (HU)	43.05 (38.85–47.71)^†	43.9 (41.02–54.07)^†	49.75 (46.38–51)^†	48.34 (44.08–51.41)^†	32.62 (25.69–41.33)	<0.01
Density of ESM (HU)	38.00±5.09	38.16±8.26	37.85±8.03^†	43.23±6.37^†	26.68 (24.7–36.53)	<0.01
Density of right P. major muscle (HU)	44.6 (41.14–48.27)^‡	51.5 (35.53–55.09)^§	53.65 (50.14–59.93)^†	58.16 (50.86–61.15)^†	39.62 (33.87–47.85)	<0.01
Density of right P. minor muscle (HU)	40.71 (36.74–46.81)	43.61 (37–49.12)^†§	49.75 (41.69–52.56)^†	53.42 (47.76–56.03)^†	32.34 (26.36–45.19)	<0.01

Notes: Values were given as mean ± SD or median (quartile). ^aComparison among five groups. *Compared between same subgroup, P<0.05. ^†Compared with healthy control group, P<0.05. ^‡Compared with CSE normal group, P<0.05. ^§Compared with CSE+COPD group, P<0.05.

Abbreviations: ESM, erector spinae muscle; P. major, pectoralis major; P. minor, pectoralis.

Pathak U, Gupta NC, Suri JC. Risk of COPD due to indoor air pollution from biomass cooking fuel: a systematic review and meta-analysis. Int J Environ Health Res. 2020;30(1):75–88. doi:10.1080/09603123.2019.1575951

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