Study | Cancer type | Population | Study type | Controlled for cigarette smoking? | Adjusted for other confounders? | OR (95% CI) | Comments |
---|---|---|---|---|---|---|---|
Wu 201326 | All cancer death | 20 033 Bangladeshi individuals | Prospective community-based | No | Yes | Adjusted=2.5 (1.08 to 5.82) | |
Auon 201391 | Lung | 150 Lebanese individuals | Case–control | Yes | Yes | 6.0 (1.78 to 20.26) | Non-significant OR after adjustment for confounders |
Koul 201192 | Lung | 751 Indian individuals | Case–control | No | No | 5.8 (3.9 to 8.6) | |
Gupta 200193 | Lung | 265 Indian individuals | Case-control | Yes | Yes | Adjusted=4.44 (1.2 to 16.44) | OR for Male heavy smokers older than 45 years |
Lubin 199094 | Lung | 148 Chinese men | Case–control | No | No | * | Increased risk with cumulative exposure |
Lubin 199295 | Lung | 1438 Chinese men | Case–control | Yes | Yes | Adjusted=1.8 (0.8 to 4.2) | Did not control for Chinese long-stem pipe smoking |
Hazelton 200196 | Lung | 12 011 Chinese men | Case–control | Yes | Yes | * | Did not control for Chinese long-stem pipe smoking |
Dar 201298 | Oesophageal | 2365 Indian individuals | Case–control | Yes | Yes | Adjusted=1.85 (1.41 to 2.44) | Higher risk with greater intensity, duration and cumulative WPS |
Malik 201099 | Oesophageal | 330 Indian individuals | Case–control | No | Yes | Adjusted=21.4 (11.6 to 39.5) | |
Nasrollahzadeh 2008100 | Oesophageal | 871 Iranian individuals | Case–control | Yes | Yes | Adjusted=1.66 (0.65 to 4.22) | OR for >32 WP-years smoking |
Sadjadi 2014101 | Gastric | 928 Iranian individuals | Prospective cohort | Yes | Yes | Adjusted=3.4 (1.7 to 7.1) | |
Karajibani 2014102 | Gastric | 92 Iranian individuals | Case–control | † | † | † | Statistically significant association was observed |
Shakeri 2013103 | Gastric | 922 Iranian individuals | Case–control | Yes | Yes | Adjusted=1.1 (0.3 to 3.3) | Also non-significant for cumulative WP use. Included a small percentage of WP smokers |
Gunaid 1995104 | Gastric and Oesophageal | 3064 Yemeni Individuals | Cross-sectional | Unclear | No | Not calculated (χ2=2.646, P<0.05) | Number of gastric cancer cases was too small to draw significant conclusions. Most WP smokers were also Qat chewers, and an individual effect could not be discerned. |
Zheng 2012105 | Bladder | 1134 Egyptian men | Case–control | Yes | Yes | Adjusted=1.1 (0.7 to 1.9) for urothelial cancer, Adjusted=0.5 (0.2 to 1.0) for squamous cancer | ORs for smoking >153 Hagar-years. ORs also insignificant for lesser exposures |
Bedwani 1997106 | Bladder | 308 Egyptian men | Case–control | Yes | Yes | Adjusted=0.8 (0.2 to 4.0) | |
Hosseini 2010107 | Prostate | 274 Iranian men | Case–control | Yes | Yes | OR=7.0 (0.9 to 56.9) | Adjusted OR for WP was also non-significant (but not reported) |
Lo 2007108 | Pancreatic | 388 Egyptian individuals | Case–control | No | Yes | Adjusted=1.6 (0.9 2.8) | WP smoking was also not exclusive of other non-cigarette forms of smoking |
Feng 2009109 | Nasopharyngeal | 1251 North African individuals | Case–control | No | Yes | Adjusted=0.49 (0.20 to 1.43) | Had small numbers of WP smokers |
*A single OR was not reported, but there was an increased risk based on mathematical modelling, which is beyond the scope of this paper.
†Only an abstract was available, which did not mention these variables.