Table 1. Characteristics of studies included in the meta-analysis.
| Study | Year | Country | Population | Metformin users |
Comparators |
|||
|---|---|---|---|---|---|---|---|---|
| Lung cancer | No lung cancer | Lung cancer | No lung cancer | |||||
| GILLIAN C. HALL | 2005 | Britain | British | 21 | 4,831 | 111 | 13,219 | |
| GILLIAN LIBBY | 2009 | Britain | British | 297 | 3,788 | 474 | 3,611 | |
| Shih-Wei Lai | 2012 | China Taiwan | Chinese | 96 | 16,520 | 33 | 2,975 | |
| Michael Bodmer | 2012 | Britain | British | 504 | 3,156 | 12,539 | 75,102 | |
| Ming-Chia Hsieh | 2012 | China Taiwan | Chinese | 45 | 3,918 | 4,281 | 63,446 | |
| Brielan B. Smiechowski | 2013 | Britain | British | 616 | 5,995 | 192 | 1,769 | |