Table 1 Characteristics of the included studies
Author, publication yr, [Ref no] | Country | Site | Study year | Design | Pros/retro | Case selection | Control selection | Sample size_case/control | Matching | Male% | Mean age ± SDb | DNA source | Measurement technique | Adjusted factorsd | Estimate of risks | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Zee, 2009 [22] | USA | 78.8% colon; 21.2%:rectum | 1982 | nested | pros | Ca (PHS cohort) | healthy men | 191/306 | age ±2years, smk, follow-up length | all males | 60.5 ± 8.66 | PBL | qPCR | BMI, al, ex | 0.8 (0.55–1.16) | 50.3%: with aspirin use |
Lee, 2010 [23] | USA | 76.3% colon; 23.7%:rectum | Dec 2005 | nested | pros | Ca (WHS cohort) | healthy women | 134/357 | age ±2years,smk, follow-up length | all females | 60.1 ± 8.68 | PBL | qPCR | age, smk, BMI, colorectal polyp, al, ex, pmp, HRT | 0.94 (0.65–1.37) | 35.1% with HRT |
Pooley, 2010 [24] | UK | CRC/ADC | Jan 1998 -Dec 2003 | nested | pros | Ca c (EPIC) | healthy | 185/406 | age, gender | female control | 45–75 | PBL | qPCR | study plate | 1.13 (0.54–2.36) |  |
Pooley, 2010 [24] | UK | CRC/ADC | March 2001-Feb 2004 | CC | retro | Ca registry (SEARCH) | healthy | 2249/2161 | age, gender | female control | 18–69 | PBL | qPCR | study plate | 3.14 (1.77–2.58) |  |
Cui, 2012 [25] | China | CRC | Dec 1996- May 2000 | nested | pros | Ca (SWHS) | healthy | 441/549 | age, date, time a, meal, antibiotic, mp | all females | 58.5 ± 8.7 | PBL | qPCR | age, date, time | 1.56 (0.92–2.64) | part of 74942 cohort |
Pellat, 2013 [26] | USA (Utah) | CRC | 1991-94 | CC (DALS) | retro | Ca (DALS) | driver license & social security lists | 249/374 (1991-94) (colon) 276/372 (1997–2002) (rectal) | age, sex | 54% | 30–79 | Cell line (colon), PBL (rectal) | qPCR | age, sex, BMI, smk, aspirin/NSAID, trans-fatty acid intake | 0.96 (0.82–1.0) | 44% on HRT, h/o aspirin, smk |
Boardman, 2014 [27] | USA | colon polyps & CRC | 2000+ | CC | retro | Ca registry & Ca (Mayo biobank) | healthy f | 598/2212 | age, gender, location. | 47% (colon); 58% (Mayo) | 48 (19–69) | PBL | qPCR | multiple | 3.53 (1.35–9.24) | chemoradio Rx; naive Ca |
Qin, 2014 [28] | China | CRC | Jan 2007- Dec 2010 | CC | retro | Ca, hospitalised | unrelated healthy e | 628/1256 | age ± 5 years, gender | 54.1% | 58,8 ± 11.8 | PBL | qPCR | smk, Al, age, sex. | 1.47 (1.09–1.99) | chemo-radio Rx & radio Rx; naive Ca |