Table 5– Odds ratio for airflow obstruction by exposures to household air pollution in never smokers
VariableFemales#Males
Subjects n (%)Crude OR (95% CI)+Adjusted OR (95% CI)+,§Subjects n (%)Crude OR (95% CI)+Adjusted OR (95% CI)+,§
Passive smoking
 No exposure1714 (4.1)1.00 (0.95–1.05)1.00 (0.95–1.05)554 (5.7)1.00 (0.92–1.09)1.00 (0.91–1.10)
 Lived with smoker ≥20 years and current exposure ≥20 h per week1588 (3.0)0.73 (0.69–0.76)0.92 (0.88–0.97)467 (4.2)0.73 (0.67–0.80)0.80 (0.72–0.87)
 Lived with smoker ≥20 years and current exposure <20 h per week6809 (4.2)1.02 (1.00–1.05)0.83 (0.81–0.85)459 (5.6)0.99 (0.90–1.09)0.83 (0.75–0.92)
 Lived with smoker <20 years1362 (4.2)1.03 (0.97–1.08)0.93 (0.88–0.98)60 (4.7)0.81 (0.63–1.05)0.77 (0.58–1.01)
Current exposure to smoking from cookingƒ
 Gas/electricity only4086 (3.3)1.00 (0.97–1.03)1 (0.95–1.06)290 (3.2)1.00 (0.89–1.12)1.00 (0.80–1.25)
 Coal3214 (4.1)1.26 (1.22–1.31)1.10 (1.04–1.17)168 (8.5)2.81 (2.40–3.29)1.01 (0.80–1.28)
 Wood3203 (5.4)1.66 (1.60–1.72)0.91 (0.88–0.95)191 (11.7)4.04 (3.47–4.69)1.04 (0.88–1.22)
 Other35 (1.6)0.49 (0.35–0.68)0.68 (0.48–0.96)5 (9.6)3.23 (1.28–8.12)1.85 (0.72–4.72)
History of exposure to smoke from cooking##
 Gas/electricity only450 (2.4)1.00 (0.91–1.10)1.00 (0.89–1.12)30 (2.2)1.00 (0.70–1.44)1.00 (0.66–1.53)
 Coal only718 (4.4)1.89 (1.75–2.03)1.29 (1.14–1.47)28 (9.8)4.72 (3.20–6.98)0.91 (0.53–1.55)
 Coal and gas/electricity807 (3.0)1.29 (1.20–1.38)1.05 (0.95–1.16)39 (3.0)1.35 (0.98–1.86)1.00 (0.66–1.50)
 Wood only1598 (6.5)2.84 (2.70–2.99)0.92 (0.86–0.98)64 (11.4)5.62 (4.33–7.29)1.13 (0.81–1.57)
 Wood and gas/electricity1278 (5.4)2.35 (2.22–2.49)0.89 (0.83–0.96)40 (6.2)2.87 (2.08–3.95)1.20 (0.83–1.74)
 Coal and wood842 (6.2)2.71 (2.53–2.91)0.97 (0.88–1.07)28 (16.6)8.65 (5.76–12.97)1.18 (0.72–1.92)
 Coal, wood and gas/electricity137 (4.0)1.71 (1.44–2.03)0.83 (0.70–0.99)3 (3.0)1.36 (0.43–4.29)0.72 (0.24–2.13)
 Other fuel combinations29 (2.7)1.16 (0.80–1.67)0.92 (0.63–1.35)2 (13.3)6.70 (1.51–29.68)2.58 (0.58–11.53)
Current exposure to smoke from heating¶¶
 Gas/electricity/central heating only1604 (2.9)1.00 (0.95–1.05)1.00 (0.91–1.10)251 (3.2)1.00 (0.88–1.13)1.00 (0.78–1.28)
 Coal1858 (2.8)0.99 (0.95–1.04)0.93 (0.88–0.99)300 (4.8)1.51 (1.35–1.70)1.07 (0.90–1.27)
 Wood1624 (4.0)1.40 (1.33–1.47)1.06 (0.99–1.13)249 (6.4)2.04 (1.80–2.32)1.04 (0.87–1.26)
 Other105 (8.8)3.29 (2.69–4.01)2.65 (2.15–3.27)6 (7.6)2.46 (1.07–5.66)2.03 (0.83–4.98)
History of exposure to smoke from heating++
 Gas/electricity/central heating only128 (1.3)1.00 (0.84–1.19)1.00 (0.79–1.27)36 (2.0)1.00 (0.72–1.39)§§
 Coal only1120 (2.8)2.28 (2.15–2.42)0.99 (0.86–1.14)212 (4.8)2.50 (2.18–2.87)§§
 Coal and gas/electricity/central heating437 (1.7)1.33 (1.21–1.46)1.02 (0.85–1.22)117 (2.8)1.40 (1.16–1.68)§§
 Wood only1387 (3.8)3.08 (2.92–3.25)0.92 (0.85–1.00)217 (6.2)3.24 (2.83–3.72)§§
 Wood and gas/electricity/central heating128 (3.6)2.97 (2.49–3.54)1.23 (1.01–1.49)18 (4.5)2.29 (1.43–3.68)§§
 Coal and wood643 (2.8)2.27 (2.10–2.45)0.77 (0.71–0.84)67 (4.4)2.25 (1.76–2.88)§§
 Coal, wood and gas/electricity/central heating36 (3.7)3.01 (2.16–4.20)1.44 (1.01–2.04)4 (3.6)1.84 (0.68–4.99)§§
 Combinations involving other fuel types114 (9.2)7.99 (6.59–9.68)2.95 (2.41–3.60)6 (6.7)3.56 (1.55–8.14)§§
  • All p-values for heterogeneity of crude odds ratios <0.0001; p<0.0001 for all adjusted odds ratios in females; p>0.05 for all adjusted odds ratios in males except passive smoking (p=0.0046). #: n=287 153; : n=30 246; +: for variables with more than two categories, odds ratios and confidence intervals are floated; §: odds ratios for airflow obstruction (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade ≥1) were adjusted for age, education, household income, region and age by region; ƒ: amongst those who cook regularly in their current home; ##: among those who have cooked regularly in all homes; ¶¶: among those who heat current their house in winter; ++: amongst those who have heated all homes in winter; §§: adjusted model did not converge for history of exposure to smoke from heating in males.