Table 1.
Demographic and clinical characteristics of cases and controls, 2006–2008
| Characteristics, % | Cases (n= 471) | Controls (n=509) |
|---|---|---|
| Age, yr | ||
| 55–64 | 115 (24.4) | 126 (24.8) |
| 65–74 | 158 (33.5) | 169 (33.2) |
| 75–85 | 198 (42.0) | 214 (42.0) |
| Female | 229 (48.6) | 254 (49.9) |
| Poverty levels, quartiles* | ||
| 1 | 97 (21.3) | 142 (28.5) |
| 2 | 129 (28.4) | 108 (21.7) |
| 3 | 122 (26.8) | 116 (23.3) |
| 4 | 107 (23.5) | 132 (26.5) |
| Poverty level, % (median [interquartile range]) | 6.52 (3.77–10.06) | 6.37 (3.13–10.87) |
| Length of enrollment with health plan before reference date, yr | ||
| 5.0–7.4 | 69 (14.6) | 88 (17.3) |
| 7.5–9.9 | 47 (10.0) | 64 (12.6) |
| >10 | 355 (75.4) | 357 (70.1) |
| Study site | ||
| A | 95 (20.2) | 95 (18.7) |
| B | 189 (40.1) | 189 (37.1) |
| C | 38 (8.1) | 76 (14.9) |
| D | 149 (31.6) | 149 (29.3) |
| Number of preventive outpatient health care visits within 5 years of reference date | ||
| 0 | 215 (45.6) | 177 (34.8) |
| 1 | 127 (27.0) | 113 (22.2) |
| 2–3 | 89 (18.9) | 137 (26.9) |
| 4+ | 40 (8.5) | 82 (16.1) |
| Family history of colorectal cancer (CRC)† | 39 (8.3) | 45 (8.8) |
| Charlson comorbidity index at baseline‡ | ||
| 0 | 393 (83.4) | 407 (80.0) |
| 1 | 56 (11.9) | 79 (15.5) |
| 2+ | 22 (4.7) | 23 (4.5) |
| Had a healthcare visit during the 2-year period at baseline‡ | 381 (80.9) | 440 (86.4) |
*
Households below 1999 federal poverty levels within the block-group from 2000 decennial census measures. Analysis was based on 455 case patients and 498 control patients with non-missing data. Higher quartiles correspond to higher levels of household poverty in the census block-group
†
This variable refers to family history that did not meet the exclusion – those with a history of colorectal cancer diagnosed in any first degree relative before age 50 or 2 or more relatives of any age, or other familial syndromes.
‡
Baseline refers to the 2-year period at the beginning of each subject’s observation period.