Table 1.
Characteristics of cases and controls.
| Cases n (%) |
Controls n (%) |
Total n (%) |
||||
|---|---|---|---|---|---|---|
| Total | 1,206 | 634 | 1,840 | |||
| Age at index colonoscopy | ||||||
| 50 to 64 years | 407 | (33.8) | 176 | (27.8) | 583 | (31.7) |
| 65 to 90 years | 799 | (66.3) | 458 | (72.2) | 1,257 | (68.3) |
| Mean (SD), years | 68.5 | (9.1) | 69.9 | (8.6) | 68.9 | (9.0) |
| Sex | ||||||
| Female | 590 | (48.9) | 293 | (46.2) | 883 | (48.0) |
| Male | 616 | (51.1) | 341 | (53.8) | 957 | (52.0) |
| Race/ethnicity | ||||||
| Non-Hispanic White | 824 | (68.3) | 444 | (70.0) | 1,268 | (68.9) |
| Hispanic | 125 | (10.4) | 68 | (10.7) | 193 | (10.5) |
| Black | 118 | (9.8) | 53 | (8.4) | 171 | (9.3) |
| Asian/Pacific Islander | 80 | (6.6) | 60 | (9.5) | 140 | (7.6) |
| Other/Unknown | 59 | (4.9) | 9 | (1.4) | 68 | (3.7) |
| Family history of colorectal cancer | ||||||
| No | 991 | (82.2) | 512 | (80.8) | 1,503 | (81.7) |
| Yes | 215 | (17.8) | 122 | (19.2) | 337 | (18.3) |
| Index colonoscopy time interval | ||||||
| 1993–1998 | 213 | (17.7) | 32 | (5.1) | 245 | (13.3) |
| 1999–2001 | 221 | (18.3) | 96 | (15.1) | 317 | (17.2) |
| 2002–2004 | 280 | (23.2) | 145 | (22.9) | 425 | (23.1) |
| 2005–2007 | 356 | (29.5) | 239 | (37.7) | 595 | (32.3) |
| 2008–2012 | 136 | (11.3) | 122 | (19.2) | 258 | (14.0) |
| Median year | 2004 | 2005 | 2004 | |||
| Time from index colonoscopy to diagnosis/reference date | ||||||
| >12 months to ≤36 months | 441 | (36.6) | 247 | (39.0) | 688 | (37.4) |
| >36 months to 10 years | 765 | (63.4) | 387 | (61.0) | 1,152 | (62.6) |
| Mean (SD) (years) | 4.1 | (2.1) | 4.3 | (2.5) | 4.2 | (2.2) |
| Health plan region | ||||||
| KPNC | 827 | (68.6) | 488 | (77.0) | 1,315 | (71.5) |
| KPSC | 379 | (31.4) | 146 | (23.0) | 525 | (28.5) |
n, number; SD, standard deviation; KPNC, Kaiser Permanente Northern California; KPSC, Kaiser Permanente Southern California.