Prevalence of Chronic Obstructive Pulmonary Disease and its Associated Factors in Nepal: Findings from a Community-based Household Survey

Figures & data

Table 1 Characteristics of Study Participants

Characteristics	Total (%)	Male (%)	Female (%)
Age group
40–49 years	477 (33.2)	179 (37.5)	298 (62.5)
50–59 years	507 (35.3)	248 (48.9)	259 (51.1)
≥60 years	454 (31.6)	234 (51.5)	220 (48.5)
Educational status
Illiterate	269 (18.7)	50 (18.6)	219 (81.4)
Non-formal education	269 (18.7)	45 (16.7)	224 (83.3)
Primary school	483 (33.6)	272 (56.3)	211 (43.7)
Secondary school	320 (22.3)	216 (66.9)	106 (33.1)
High school and above	97 (6.6)	80 (82.5)	17 (17.5)
Ethnicity
Dalit	212 (14.7)	86 (40.6)	126 (59.4)
Disadvantaged janajati	205 (14.3)	85 (41.5)	120 (58.5)
Relatively advantaged janajati	244 (17.0)	109 (44.7)	135 (55.3)
Upper caste	777 (54.0)	381 (49.0)	396 (51.0)
Marital status
Currently married	1194 (83.0)	630 (52.8)	564 (47.2)
Currently not married (divorced, widowed, single)	244 (17.0)	31 (12.7)	213 (87.3)
Occupational status
Employee	238 (16.6)	155 (65.1)	83 (34.9)
Agriculture	590 (41.0)	253 (42.9)	337 (57.1)
Homemaker	263 (18.3)	8 (3.0)	255 (97.0)
Labour/wage worker	74 (5.2)	61 (82.4)	13 (17.6)
Retired/pensioner	84 (5.8)	83 (98.8)	1 (1.2)
Unemployed	189 (13.1)	101 (53.4)	88 (46.6)
Family size
<5 members	759 (52.8)	330 (43.5)	429 (56.5)
≥5 members	679 (47.2)	331 (48.7)	348 (51.3)
Physical activity
Low (<600 MET)	855 (59.5)	414 (48.4)	441 (51.6)
Medium (600–2999MET)	483 (33.6)	286 (59.2)	197 (40.8)
High (≥3000MET)	100 (7.0)	50 (50)	50 (50)
Average body mass index (BMI) kg/m^2	25.5 (4.6)	24.2 (4.2)	26.5 (4.7)
Smoking status
Never smoker	829 (57.7)	309 (37.3)	520 (62.7)
Former smoker	352 (24.5)	202 (57.4)	150 (42.6)
Current smoker	257 (17.9)	150 (58.4)	107 (41.6)
Smoking >10 pack years
Yes	430 (70.6)	251 (58.4)	179 (41.6)
No	179 (20.4)	101 (56.4)	78 (43.6)
Secondhand smoking
Yes	358 (24.9)	157 (43.8)	201 (56.2)
No	1080 (75.1)	504 (46.7)	576 (53.3)
History of childhood lung infection
Yes	96 (6.7)	45 (46.9)	51 (53.1)
No	1342 (93.3)	616 (45.9)	726 (54.1)
Occupational exposure to dust and dirt
Yes	1189 (82.7)	484 (40.7)	705 (59.3)
No	249 (17.3)	177 (71.1)	72 (28.9)
Use of mosquito repellent
Yes	1024 (71.2)	484 (47.3)	540 (52.7)
No	414 (28.8)	177 (42.8)	237 (57.2)
Biomass fuel exposure
Yes	525 (36.5)	288 (54.9)	237 (45.1)
No	913 (63.5)	489 (53.6)	424 (46.4)
Chimney in the kitchen
Yes	421 (29.3)	228 (54.2)	193 (45.8)
No	1017 (70.7)	549 (54.0)	468 (46.0)
Black smoke mark in kitchen wall
Yes	827 (57.5)	364 (44.0)	463 (56.0)
No	611 (42.5)	297 (48.6)	314 (51.4)
History of tuberculosis
Yes	37 (2.6)	30 (81.1)	7 (18.9)
No	1401 (97.4)	631 (45.0)	770 (55.0)
Modified MRC Dyspnea scale
mMRC Grade 0	446 (31.0)	224 (50.2)	222 (49.8)
mMRC Garde 1	785 (54.6)	345 (44.0)	440 (56.0)
mMRC Garde 2	104 (7.2)	31 (29.8)	73 (70.2)
mMRC Garde 3	52 (3.6)	30 (57.7)	22 (42.3)
mMRC Garde 4	51 (3.6)	31 (60.8)	20 (39.2)

Table 2 Lung Function Parameters

	Total		Male		Female
	Mean ±SD	% Predicted ±SD	Mean ±SD	% Predicted ±SD	Mean ±SD	% Predicted ±SD
Pre-bronchodilation spirometry
FVC (L)	2.5 ± 0.7	89.9 ± 19.2	3.0 ± 0.7	89.0 ± 17.9	2.1 ± 0.5	90.7 ± 20.2
FEV1 (L)	1.9 ± 0.6	94.4 ± 24.8	2.3 ± 0.6	91.4 ± 23.4	1.6 ± 0.5	96.8 ± 25.8
FEV1/FVC	75.5 ± 8.9	102.4 ± 11.5	74.2 ± 10.2	100.4 ± 13.1	76.7 ± 7.5	104.1 ± 9.6
Number of participants	1438		661		777
Change in post-bronchodilation spirometry
FVC (L)	0.18 ± 0.14	6.50 ± 4.89	0.20 ± 0.16	6.53 ± 5.12	0.14 ± 0.10	6.44 ± 4.57
FEV1 (L)	0.15 ± 0.10	7.99 ± 4.98	0.16 ± 0.11	7.46 ± 4.65	0.12 ± 0.08	8.74 ± 5.35
FEV1/FVC	0.02 ± 0.01	2.74 ± 2.67	0.02 ± 0.01	2.34 ± 2.27	0.02 ± 0.02	3.30 ± 3.11
Number of participants	218		128		90

Figure 1 Distribution of respiratory symptoms by sex among study participants (n=1438).

Figure 2 (A) Prevalence of COPD and severity classification by LLN criteria (n=1438). (B) Prevalence of COPD and severity classification by GOLD criteria (n=1438).

Table 3 Prevalence of COPD by GOLD Criteria and LLN Criteria

Characteristics	COPD Prevalence by GOLD Criteria			COPD Prevalence by LLN Criteria
	Percentage	(95% CI)	p-value	Percentage	(95% CI)	p-value
Sex			<0.001			<0.001
Male (n=661)	10.9	(8.7–13.5)		7.6	(5.8–9.9)
Female (n=777)	6.4	(4.9–8.4)		3.5	(2.4–5.0)
Age category			<0.001			<0.001
40–49 years (n=477)	1.7	(0.8–3.3)		1.1	(0.4–2.5)
50–59 years (n=507)	5.5	(3.8–7.9)		3.9	(2.6–6.0)
≥60 years (n=454)	18.9	(15.6–22.8)		11.5	(8.8–14.7)
Ethnicity			<0.01			<0.001
Dalit (n=212)	10.4	(6.9–15.3)		8.0	(5.0–12.5)
Disadvantaged janajati (n=205)	8.3	(5.2–12.9)		4.9	(2.6–8.8)
Relatively advantaged janajati (n=244)	3.3	(1.6–6.4)		0.8	(0.2–3.2)
Upper caste (n=777)	9.7	(7.8–11.9)		6.2	(4.7–8.1)
Occupational status			<0.001			<0.001
Employee (n=238)	4.2	(2.3–7.6)		2.5	(1.1–5.5)
Agriculture (n=590)	7.3	(5.5–9.7)		5.1	(3.6–7.2)
Housemaker (n=263)	5.7	(3.5–9.3)		3.0	(1.5–6.0)
Labor/wage worker (n=74)	4.1	(1.3–11.8)		2.7	(0.7–10.2)
Retired/Pensioner (n=84)	7.1	(3.2–15.0)		3.6	(1.2–10.5)
Unemployed (n=189)	23.8	(18.3–30.4)		14.8	(10.4–20.6)
Educational status			<0.001			<0.001
Illiterate (n=269)	17.8	(13.7–22.9)		11.5	(8.2–15.9)
Nonformal education (n=269)	8.9	(6.1–13.0)		4.5	(2.6–7.7)
Primary school (n=483)	6.2	(4.4–8.8)		4.1	(2.69–6.3)
Secondary school (n=320)	5.0	(3.1–8.01)		3.8	(2.1–6.5)
High school and above (n=97)	4.1	(1.6–10.5)		2.1	(0.5–7.9)
Marital status			<0.001			0.22
Currently married (n=1194)	7.5	(6.1–9.1)		5.0	(3.9–6.4)
Currently not married (divorced, widowed, single) (n=244)	13.5	(9.8–18.4)		7.0	(4.4–10.9)
Family size			0.941			0.75
<5 members (n=759)	8.4	(6.7–10.6)		5.5	(4.1–7.4)
≥5 members (n=679)	8.5	(6.7–10.9)		5.2	(3.7–7.1)
Average body mass index (n=1438)	22.1	(21.3–22.8)		21.1	(20.1–21.0)
Physical activity			0.001			0.013
Low (<600 MET) (n=855)	10.6	(8.7–12.9)		6.7	(5.2–8.6)
Medium (600–2999MET) (n= 483)	4.8	(3.2–7.1)		2.9	(1.7–4.8)
High (≥3000MET) (n=100)	8.0	(4.1–15.2)		6.0	(2.7–12.7)
Secondhand smoking			<0.001			0.02
Yes (n=358)	13.4	(10.3–17.4)		7.8	(5.5–11.1)
No (n=1080)	6.9	(5.5–8.5)		4.5	(3.4–6.0)
Smoking status			<0.001			<0.001
Never Smoker (n=829)	3.1	(2.1–4.6)		1.6	(0.9–2.7)
Former Smoker (n=352)	13.9	(10.7–18.0)		9.9	(7.2–13.5)
Current Smoker (n=257)	18.3	(14.0–23.5)		11.3	(8.0–15.8)
Smoking >10 pack years			0.01			0.01
Yes	18.1	(14.8–22.1)		12.6	(9.7–16.1)
No	10.1	(6.4–15.4)		5.6	(8.3–13.2)
Occupational exposure to dust & dirt			0.43			0.68
No (n=249)	7.2	(4.6–11.2)		4.8	(2.8–8.3)
Yes (n=1189)	8.8	(7.3–10.5)		5.5	(4.3–6.9)
Exposure to biomass fuel			<0.001			<0.001
No (n=913)	6.2	(4.8–8.0)		3.2	(2.2–4.5)
Yes (n=525)	12.4	(9.8–15.5)		9.1	(7.0–11.9)
Black smoke mark in kitchen wall			0.002			0.006
No (n=611)	6.6	(4.8–8.8)		3.4	(2.3–5.2)
Yes (n=827)	9.9	(8.1–12.2)		6.8	(5.3–8.7)
Chimney in kitchen			0.03			0.001
Yes (n=421)	5.9	(4.0–8.6)		2.9	(1.6–5.0)
No (n=1017)	9.5	(7.9–11.5)		6.4	(5.0–8.1)
Use of mosquito repellent			0.062			0.182
Yes (n=1024)	7.3	(5.1–10.2)		5.9	(4.6–7.5)
No (n=414)	9.0	(7.4–10.9)		4.1	(2.6–6.5)
History of childhood lung infection			<0.001			<0.001
Yes (n=96)	26.0	(18.2–35.7)		18.8	(12.1–27.8)
No (n=1342)	7.2	(6.0–8.7)		4.4	(3.4–5.6)
History of tuberculosis			0.26			0.13
Yes (n=37)	8.4	(7.0–9.9)		10.8	(4.1–25.5)
No (n=1401)	13.5	(5.7–28.7)		5.2	(4.2–6.5)
Modified MRC Dyspnea scale			<0.001			<0.001
mMRC Grade 0	2.5	(1.4–4.4)		1.1	(0.5–2.7)
mMRC Garde 1	5.2	(3.9–7.0)		3.1	(2.1–4.5)
mMRC Garde 2	16.4	(10.4–24.7)		8.7	(4.6–15.8)
mMRC Garde 3	44.2	(31.4–57.8)		30.8	(19.8–44.5)
mMRC Garde 4	58.8	(44.9–71.4)		45.1	(32.1–58.8)
Total (n=1438)	8.5	(7.1–10.0)		5.4	(4.3–6.7)

Table 4 Factors Associated with COPD (Adjusted Model)

Variables	COPD by LLN Criteria (LLN-COPD)		COPD by GOLD Criteria (GOLD-COPD)
	OR (95% CI)	p - value	OR (95% CI)	p-value
Age group
40–49 years	1		1
50–59 years	2.4 (0.9–6.7)	0.09	2.2 (1.0–5.1)	0.06
≥60 years	4.4 (1.6–11.9)	0.004	5.9 (2.6–13.4)	<0.001
Body mass index (BMI) kg/m^2	0.8 (0.7–0.9)	<0.001	0.9 (0.8–0.9)	<0.001
Physical Activity
Low (<600 MET)	1		1
Medium (600–2999MET)	0.3 (0.2–0.6)	<0.001	0.3 (0.2–0.6)	<0.001
High (≥3000MET)	0.6 (0.2–1.8)	0.39	0.7 (0.3 −1.8)	0.48
Childhood lung infection
No	1		1
Yes	6.2 (3.1–12.3)	<0.001	5.8 (3.2–10.5)	<0.001
Smoking status
Never Smoker	1		1
Current Smoker	3.9 (1.9–8.1)	<0.001	3.6 (2.0–6.3)	<0.001
Former Smoker	3.4 (1.7–7.0)	<0.001	2.2 (1.3–3.9)	<0.001
Exposure to biomass fuel smoke
No	1		1
Yes	2.7 (1.6–4.6)	<0.001	1.7 (1.1–2.7)	0.014
Education category
Illiterate	-		1
Non-formal education	-		0.7 (0.4–1.2)	0.18
Primary school	-		0.5 (0.3–0.9)	0.02
Secondary school	-		0.6 (0.3–1.1)	0.09
High school and above	-		0.3 (0.1–1.0)	0.05