Table 1. Descriptive characteristics of study populations.
| Study | Design | Country | Years of Inception/Recruitment | Years of Diagnosis | Cases | Controls | Mean Age (range, yrs) | Female No. (%) | Covariates Used in Base Model Analysisa | Definition of Regular Use of Aspirin and/or NSAIDsb |
|---|---|---|---|---|---|---|---|---|---|---|
| CCFR | case-control | U.S., Canada, Australia | 1998-2006 | 1998-2006c | 1163 | 978 | 54.3 (17-81) | 1067 (49.8) | age, gender, 3 PCs, center | At least twice a week for more than a month |
| DACHS | case-control | Germany | 2003-2010 | 2003-2010 | 2339 | 2180 | 68.7 (33-99) | 1801 (39.9) | age, gender, 3 PCs | At least 1 time per month for at least one year |
| DALS | case-control | U.S. | 1991-1994 | 1991-1994 | 1115 | 1173 | 63.8 (28-79) | 1027 (44.9) | age, gender, 3 PCs, center | At least 3 times per week for at least one month |
| HPFS | cohort | U.S. | 1986 | 1986-2008 | 403 | 401 | 65.2 (48-83) | 0 (0) | age, 3 PCs | Currently taking at least 2 times per week |
| NHS | cohort | U.S. | 1976 | 1976-2008 | 553 | 955 | 59.7 (44-69) | 1508 (100) | age, 3 PCs | On average 5 or more days per month |
| OFCCR | case-control | Canada | 2000-2006 | 1998-2003 | 553 | 519 | 62.1 (29-77) | 577 (53.8) | age, gender, 3 PCs | At least twice a week for more than a month |
| PMH-CCFR | case-control | U.S. | 1998-2003 | 1998-2002d | 280 | 122 | 62.8 (48-73) | 402 (100) | age, 3 PCs | At least twice a week for more than a month |
| PLCO | cohort | U.S. | 1993-2001 | 1994-2009 | 485 | 415 | 63.6 (55-75) | 382 (42.4) | age, gender, 3 PCs, center | At least twice a week in the last 12 month |
| VITAL | cohort | U.S. | 2000-2002 | 2000-2009 | 277 | 279 | 66.5 (50-76) | 268 (48.2) | age, gender, 3 PCs | At least four or more days per week for a year |
| WHI | cohort | U.S. | 1993-1998 | 1993-2011 | 1466 | 1531 | 66.3 (50-79) | 2997 (100) | age, 3 PCs, region | At least once a week for at least the last 2 weeks |
PC: principal component
CCFR: Colon Cancer Family Registry; DACHS: Darmkrebs: Chancen der Verhütung durch Screening study; DALS: Diet, Activity and Lifestyle Study;
HPFS: Health Professionals Follow-up Study; NHS: Nurses’ Health Study; OFCCR: Ontario Familial Colorectal Cancer Registry;
PMH-CCFR: Postmenopausal Hormone study-Colon Cancer Family Registry; PLCO: Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial;
VITAL: VITamins And Lifestyle; WHI: Women's Health Initiative
In the Multivariable-Adjusted Model, in addition to the covariates adjusted in the Base Model, those colorectal cancer-related factors, including smoking status (never, former, or current smoker), BMI, alcohol consumption and red meat consumptions, are also adjusted.
Includes regular use of aspirin-only, NSAIDs-only, or both aspirin and NSAIDs.
All cases diagnosed between 1998-2006, except two cases for which the year of diagnosis is 1985 and 1995
All cases diagnosed between 1998-2002, except four cases for which the year of diagnosis is 1983, 1984, 1990, 1991