Table 2

Summary of 14 case-control studies included in the systematic review; Lissowska et al5 was included in the pooled analysis by Hosgood et al14

Author and study locationStudy design (all case-control); numbers of cases and controls; outcome assessmentCooking fuel type(s); assessment of duration of useReference category clearly using clean fuel(s)Adequacy of adjustmentNon-smoker analysis*Results: adjusted
OR (95% CI)
cases: 67 (F);
pathologically confirmed controls: 46 (F)
Biomass for cooking;
duration: current fuel use
YEs: use of LPGModerateNot reportedWomen: use of biomass for cooking:
OR=3.59 (1.07 to 11.97)
Gupta, India15Hospital-based
cases: 235 (M), 30 (F); pathologically confirmed
controls: 525 (2 per case)
Wood for cooking and for heating;
duration: <45 and >45 years of use
No: never used woodModerateNot reportedUse of wood for cooking:
Men: 1–45 years: OR=0.94 (0.58 to 1.54)
>45 years: OR=0.87 (0.58 to 1.30)
Women: 1–45 years: OR=0.74 (0.20 to 2.65)
>45 years: OR=1.11 (0.34 to 3.60)
Use of wood for heating:
Men: 1–45 years: OR=2.62 (0.47 to 14.5)
Women: 1–45 years: OR= 2.78 (0.97 to 7.98)
Sapkota, India11Hospital-based
cases: 793 (88% M); 80% cases pathologically confirmed
controls: 718
Wood for cooking;
duration: always used wood
Yes: always used modern cooking fuel†ModerateOnly for all solid fuels (biomass and other solid fuels)Use of wood for cooking:
Men: OR=1.30 (0.90 to 1.87)
Women: OR=1.01 (0.42 to 2.41)
Men and women non-smokers: OR=0.75 (0.45 to 1.24)
Gao, China18Population-based
cases: 672 (F) 80%; pathologically confirmed
controls: 735
Wood for cooking;
duration: current wood use
No: not currently using woodModerateNot reportedWomen:
Use of wood for cooking:
OR=1.0 (0.6 to 1.8)
Liu China16Hospital-based
cases: 224 (M) and 92 (F); 32% pathologically confirmed
controls: 224 (M) and 92 (F)
Wood for cooking;
duration: current wood use
No: not currently using woodWeakNot reportedUse of wood for cooking:
Men: estimated (unadjusted) OR=1.39 (0.44 to 4.42)
Women: estimated (unadjusted) OR=0.84 (0.14 to 5.0)
Ko, Taiwan19Hospital-based
cases: 105 (F); pathologically confirmed
controls: 105 (F)
Wood or charcoal for cooking; duration: cooking before 20 years of age, 20–40 and after 40Yes: no cooking/gasModerateCases are non-smoking womenWomen: use of wood/charcoal for cooking:
OR=2.7 (0.9 to 8.9)
Koo, Hong Kong20Population-based (poorly described)
cases: 200 (F); no information on histology
controls: 200 (F)
Wood or grass for cooking;
duration: ever used wood/grass
No: never used wood/grassWeakNot reportedWomen: use of biomass for cooking: OR=0.74 (95% CI not reported), p=0.50
Lee, Taiwan4Hospital-based
cases: 236 (M) and 291 (F); pathologically confirmed
controls: 805 (M and F)
Wood or charcoal for cooking; duration: asked about habitual cooking practice age 20–40 yearsYEs: no cooking or gasStrongNot reportedWomen: use of wood/charcoal for small-cell carcinoma: OR=3.5 (0.9 to12.9);
use of wood/charcoal for adeno-carcinoma: OR=3.3 (1.4 to 8.0)
Sobue, Japan6Hospital-based
cases: 144 (F); pathologically confirmed
controls: 731 (F)
Wood or grass for cooking;
duration: asked about fuel use at both 15 and 30 years of age
No: not wood or grassModerateCases are non-smoking womenWomen: use of biomass for cooking:
OR=1.77 (1.08 to 2.91)
Malats, 6 European; Brazil22Hospital-based
cases: 17 (M) and 105 (F); pathologically confirmed
controls: 34 (M) and 87 (F)
Wood for cooking or heating;
duration: more than 20 years use
No: not statedStrongCases are non-smoking (M/F combined)Men and women:
use of wood for heating or cooking:
OR=2.50 (1.00 to 6.25)
Hernandez-Garduno, Mexico7Hospital-based
cases: 113 (F) pathologically confirmed
controls‡: 273 (F)
Wood for cooking;
duration: 1–20, 21–50 and >50 years of use
No: never used woodStrongCases are non-smoking womenWomen: use of wood for cooking: 1–20 years: OR=0.6 (0.3 to 1.2); 21–50 years: OR=0.6 (0.3 to 1.3);
>50 years: OR=1.9 (1.1 to 3.5)
Lissowska, 7 European countries5Hospital and population
cases: 1378 (M) and 323 (F); pathologically confirmed
controls: 1422 (M) and 429 (F)
Wood for cooking and heating;
duration: exclusive use of wood for cooking
Yes: never used solid fuelModerateNot reportedUse of wood for cooking:
Men: OR=1.24 (1.00 to 1.54)
Women: OR=1.07 (0.67 to 1.71)
Tang, Chinese in Singapore21Hospital-based
cases: 703 (all F); 674 (96%) pathologically confirmed, remainder radiologically,
controls: 1578 (all F)
Wood for cooking;
duration: frequency of use
No: less than daily use of woodStrongYes (all women)Women: use of wood for cooking:
current/ex-smokers: OR=1.25 (0.74 to 2.11);
never-smokers: OR=0.81 (0.56 to 1.17)
Hosgood, pooled studies from Europe, USA, Canada, Asia14Hospital and population
cases: 4194 (M and F); pathologically confirmed for 3749 (89%) cases, not reported for any of the 445 cases in one study; controls: 5189 (M and F). Incorporates Lissowska5
Wood for cooking or heating (only from European and North American centres);
duration: lifetime predominant wood use
Yes: clean fuels including electricity, oil and gasStrongYes, for M and F combinedUse of wood for cooking and/or heating
All subjects:
men: OR=1.19 (1.02 to 1.39)
women: OR=1.19 (0.94 to 1.51)
By smoking status (M and F):
ever smoke: OR=1.22 (1.05 to 1.42)
never smoke: OR=1.01 (0.74 to 1.37)
  • *When not stratified for smoking, all studies with moderate or strong adjustment controlled for smoking.

  • †Clean fuel reference group includes kerosene.

  • ‡Control group included subjects with TB, interstitial lung disease, COPD, asthma, miscellaneous pulmonary conditions.

  • §Reanalysis by International Agency for Research on Cancer (IARC) for the current review to provide separate estimates for men and women, and for cooking and heating; also exposure–response analysis based on years of wood use (see text).