Factors Associated with Chronic Obstructive Pulmonary Disease: A Hospital-Based Case–Control Study

Figures & data

Table 1 Demographic Characteristics

Variables	Cases	Controls	p-Value
	N=41	N=82
Gender, n (%)
Male	25 (61)	47 (57)	0.698
Female	16 (39)	35 (43)
Age (years), median (IQR)	70 (56–78)	68 (55–77)	0.654
Marital status, n (%)
Single	4 (10)	1 (1)	0.142
Widow/widower	8 (19)	14 (17)
Separated	2 (5)	4 (5)
Married	27 (66)	63 (77)
Level of education, n (%)
Tertiary	7 (17)	9 (11)	0.653
Secondary	7 (17)	20 (24)
Primary	15 (37)	32 (39)
None	12 (29)	21 (26)
Occupation, n (%)
Subsistence farming	25 (61)	48 (59)	0.968
Farming (with animals)	4 (10)	10 (12)
Business	2 (5)	5 (6)
Others	10 (24)	19 (23)
Address, n (%)
Mbarara	12 (29)	38 (46)	0.221
Isingiro	10 (24)	12 (15)
Bushenyi	2 (5)	6 (7)
Others	17 (42)	26 (32)
BMI (kg/m^2), median (IQR)	21 (19–30)	22 (19–25)	0.750
Pre FEV1/FVC, median (IQR)	56 (50–63)	77 (72–81)	0.000
Pre FVC (% predicted), median (IQR)	85 (72–102)	100 (89–118)	0.010
Post FEV1/FVC, median (IQR)	59 (52.2–66.5)
% Oxygen saturation post-6MWT, median (IQR)	92 (87–96)
BODE index, median (IQR)	3 (1–5)
% 4-year survival, median (IQR)	67 (57–80)

Abbreviations: IQR, interquartile range; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; 6MWT, Six-Minute Walk Test.

Table 2 Medical and Smoking History

Variables	Cases	Controls	p-Value
	N=41	N=82
Physician-Diagnosed Conditions
HIV, n (%)
Negative	29 (71)	54 (66)	0.639
Positive	4 (10)	6 (7)
Unknown	8 (19)	22 (27)
Asthma, n (%)
No	35 (85)	80 (98)	0.010
Yes	6 (15)	2 (2)
Allergy, n (%)
No	21 (51)	63 (77)	0.004
Yes	20 (49)	19 (23)
TB, n (%)
No	38 (93)	81 (99)	0.072
Yes	3 (7)	1 (1)
Tobacco Exposure
Ever smoked, n (%)
No	13 (32)	48 (59)	0.005
Yes	28 (68)	34 (41)
Age at start (years), median (IQR)	15 (12–18)	15 (12–20)	0.997
Quit smoking, n (%)
No	12 (43)	4 (12)	0.760
Yes	16 (57)	23 (85)
Years of smoking, median (IQR)	35 (18–45)	26.5 (10–38)	0.900
Current smoking, n (%)
No	29 (71)	72 (88)	0.020
Yes	12 (29)	10 (12)

Abbreviations: HIV, human immunodeficiency virus; TB, pulmonary tuberculosis; IQR, interquartile range.

Table 3 Biomass Exposure and Environmental Pollution

Variables	Cases	Controls	p-Value
	N=41	N=82
Outdoors (hours per day), mean (SD)	10 (2.7)	11 (2.4)	0.009
Indoors (hours per day), mean (SD)	14 (2.8)	13 (2.4)	0.009
Hours spent cooking, median (IQR)	2 (0–4)	1 (0–3)	0.196
Hours spent digging, median (IQR)	4 (0–6)	4 (2–6)	0.196
Primary fuel, n (%)
Charcoal	7 (17)	15 (18)	0.868
Firewood	34 (83)	67 (82)
Duration of primary fuel use (years), mean (SD)	45 (17)	42 (16)	0.375
Cooking primary responsibility, n (%)
No	20 (49)	38 (46)	0.798
Yes	21 (51)	44 (54)
Age at start of cooking (years), median (IQR)	10 (8–18)	12 (10–15)	0.902
Hours per day inside kitchen, mean (SD)	3.8 (2.2)	3.5 (1.9)	0.469
Smoke exposure (hours per year), n (%)
˂500	5 (26)	5 (13)	0.202
˃500	14 (74)	34 (87)
Burning trash, n (%)
No	17 (41)	34 (41)	1.000
Yes	24 (59)	48 (59)
Primary source of light, n (%)
Kerosene lamps	33 (81)	65 (79)	0.912
Candles	3 (7)	5 (6)
Electricity	5 (12)	12 (15)

Abbreviations: SD, standard deviation; IQR, interquartile range.

Table 4 Results of Bivariate Analysis Showing Risk Factors for COPD

Covariates	Odds Ratio	95% CI	p-Value
Subsistence farming	1.1	0.51–2.42	0.793
HIV positive	0.8	0.48–1.35	0.400
TB disease	5.9	0.62–57.68	0.121
Atopy	3.3	1.39–7.72	0.006
Smoking	4.4	1.59–11.99	0.004
Charcoal use	Ref
Firewood use	1.1	0.39–3.12	0.860
Not involved in cooking	Ref
Cooking primary responsibility	0.8	0.23–2.61	0.696
Kitchen smoke: annual exposure hours	0.4	0.06–2.64	0.355
Burning trash	1.0	0.48–2.09	1.000
Electric lamps or candle use	Ref
Kerosene lamps	1.7	0.61–4.52	0.321

Abbreviations: HIV, human immunodeficiency virus; TB, pulmonary tuberculosis.

Table 5 Results of Multivariate Analysis Showing Risk Factors for COPD

Covariates	Odds Ratio	95% CI	p-Value
Asthma	4	0.72–21.79	0.110
Tuberculosis	5.3	0.43–63.75	0.192
Smoking	3.5	1.20–10.10	0.022
Allergy	3.0	1.19–7.72	0.020