Table 1.
Characteristics of 17 E2C2 studies pooled to investigate the association between breastfeeding and endometrial cancer risk among parous women
| Study Study name | Acronym | Country | Years of recruitment/diagnosis | Cases (8981) N | Controls (17241) N | Ever breastfed N (%) | Median total breastfeeding (months)* | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Case-control studies | cases | controls | cases | controls | |||||||
| Alberta Case-Control Study on Endometrial Cancer17 | ALTA | Canada | 2002–2006 | 441 | 922 | 298 (68) | 692 (75) | 6 | 9 | ||
| Australian National Endometrial Cancer Study29 | ANECS | Australia | 2005–2007 | 1119 | 659 | 913 (82) | 561 (85) | 10 | 12 | ||
| Connecticut Endometrial Cancer Study18 | CONN | USA | 2004–2009 | 505 | 558 | 218 (43) | 299 (54) | 8 | 12 | ||
| Estrogen, Diet, Genetics, and Endometrial Cancer19 | EDGE | USA | 2001–2005 | 370 | 407 | 159 (43) | 188 (46) | 6 | 9 | ||
| Fred Hutchinson Cancer Research Center25 | FHCRC | USA | 1994–2005 | 703 | 737 | 452 (64) | 514 (70) | 6 | 7 | ||
| Italian Multi Centre Study20 | IMS | Italy | 1992–2006 | 386 | 780 | 303 (79) | 592 (76) | 9 | 10 | ||
| Patient Epidemiologic Data System30 | PEDS | USA | 1982–1998 | 401 | 423 | 195 (49) | 261 (62) | 6 | 7 | ||
| Polish Endometrial Cancer Study21 | PECS | Poland | 2000–2003 | 447 | 1701 | 366 (82) | 1388 (82) | 8 | 7 | ||
| Shanghai Endometrial Cancer Study22 | SECS | China | 1997–2004 | 1089 | 1161 | 896 (83) | 1003 (86) | 14 | 13 | ||
| Turin Case Control Study | TURIN | Italy | 1998–2008 | 219 | 260 | 170 (78) | 196 (75) | 8 | 6.5 | ||
| USC LA case control24 | USC | USA | 1987–1993 | 660 | 709 | 411 (63) | 468 (66) | 3 | 5 | ||
| US Endometrial Cancer Study8 | USE | USA | 1987–1990 | 316 | 290 | 191 (60) | 181 (62) | 4 | 6 | ||
| Western New York Diet Study23 | WNYDS | USA | 1986–1991 | 185 | 532 | 91 (49) | 277 (52) | 3 | 6 | ||
| Women’s Insight and Shared Experience31 | WISE | USA | 1999–2002 | 512 | 1418 | 217 (42) | 677 (48) | 6 | 8 | ||
| Cohort studies | |||||||||||
| Black Women’s Health Study15 | BWHS | USA | 1995–2013 | 202 | 899 | 79 (39) | 388 (43) | 5 | 5 | ||
| Nurses’ Health Study16 | NHS | USA | 1986–2012 | 1197 | 4788 | 771 (64) | 3069 (64) | 5 | 5 | ||
| Swedish Women’s Lifestyle and Health Study14 | SWLHS | Sweden | 1993–2012 | 229 | 997 | 202 (88) | 921 (92) | 8 | 9 | ||
*
Amongst women who breastfed