Table 1. Characteristics of the included studies.
| Study name Principal investigator | Country | Enrolment period | Matching variables | Cases | Controls Source | Total |
|---|---|---|---|---|---|---|
| EAGLE
MT Landi (Pesatori et al, 2013) |
Italy |
2002–2005 |
Age, residential area |
407 |
499
Population |
906 |
| ESTHER
H Brenner |
Germany |
2000–2003 |
Age |
52 |
52
Population |
104 |
| MLCS
CC Harris (Meinhold et al, 2011) |
USA |
1998–2010 |
Age, ethnicity, pack-years, hospital |
540 |
777
Population+hospital |
1317 |
| NELCS
EJ Duell (Heck et al, 2009) |
USA |
2005–2008 |
Age |
150 |
148
Population |
298 |
| TORONTO
JR McLaughlin (Brenner et al, 2010) |
Canada |
1997–2002 |
Ethnicity |
235 |
558
Population+hospital |
793 |
| WELD
AG Schwartz (Schwartz et al, 2007) |
USA |
2002–2007 |
Age, ethnicity |
577 |
575
Population |
1152 |
| Total | 1961 | 2609 | 4570 |