Table 1.
Main characteristic of participants in the PLCO cancer screening trial by carrot intake.
| Variables | Q1 (n = 20945) | Q2 (n = 18997) | Q3 (n = 22183) | Q4 (n = 18881) | Q5 (n = 18644) | p-value |
|---|---|---|---|---|---|---|
| Age (y), mean (SD) | 62.1 (5.2) | 62.5 (5.3) | 62.2 (5.2) | 63.0 (5.4) | 62.3 (5.3) | <0.001 |
| Female (n, %) | 9,940 (47.5%) | 8,190 (43.1%) | 10,782 (48.6%) | 12,116 (64.2%) | 10,329 (55.4%) | <0.001 |
| Arm (n, %) | 0.82 | |||||
| Screen | 10,621 (50.7%) | 9,689 (51.0%) | 11,366 (51.2%) | 9,599 (50.8%) | 9,466 (50.8%) | |
| Control | 10,324 (49.3%) | 9,308 (49.0%) | 10,817 (48.8%) | 9,282 (49.2%) | 9,178 (49.2%) | |
| Smoking (n, %) | <0.001 | |||||
| Never | 8,443 (40.3%) | 8,535 (44.9%) | 10,137 (45.7%) | 10,626 (56.3%) | 9,959 (53.4%) | |
| Current | 3,075 (14.7%) | 1,848 (9.7%) | 2,107 (9.5%) | 1,047 (5.5%) | 1,019 (5.5%) | |
| Former | 9,424 (45.0%) | 8,612 (45.3%) | 9,935 (44.8%) | 7,206 (38.2%) | 7,664 (41.1%) | |
| Education (n, %) | <0.001 | |||||
| ≤High school | 10,059 (48.0%) | 8,048 (42.4%) | 9,738 (43.9%) | 7,304 (38.7%) | 6,692 (35.9%) | |
| ≥Some college | 10,843 (51.8%) | 10,909 (57.4%) | 12,405 (55.9%) | 11,543 (61.1%) | 11,920 (63.9%) | |
| BMI (n, %) | <0.001 | |||||
| <25.0 kg/m2 | 6,518 (31.1%) | 5,958 (31.4%) | 6,913 (31.2%) | 7,137 (37.8%) | 6,631 (35.6%) | |
| ≥25.0 kg/m2 | 14,127 (67.4%) | 12,806 (67.4%) | 14,967 (67.5%) | 11,504 (60.9%) | 11,786 (63.2%) | |
| Race (n, %) | <0.001 | |||||
| White, Non-hispanic | 17,781 (84.9%) | 17,269 (90.9%) | 20,485 (92.3%) | 17,546 (92.9%) | 17,660 (94.7%) | |
| Other | 3,150 (15.0%) | 1,721 (9.1%) | 1,693 (7.6%) | 1,330 (7.0%) | 980 (5.3%) | |
| Drinking (n, %) | <0.001 | |||||
| Never | 1,907 (9.1%) | 1,684 (8.9%) | 1,972 (8.9%) | 2,312 (12.2%) | 2,044 (11.0%) | |
| Former | 3,641 (17.4%) | 2,760 (14.5%) | 3,152 (14.2%) | 2,368 (12.5%) | 2,481 (13.3%) | |
| Current | 14,683 (70.1%) | 14,052 (74.0%) | 16,529 (74.5%) | 13,650 (72.3%) | 13,628 (73.1%) | |
| Total energy intake (kcal/d), mean (SD) | 1570.1 (661.3) | 1664.6 (649.4) | 1731.1 (660.4) | 1747.9 (634.4) | 1903.0 (679.4) | <0.001 |
| Marital status (n, %) | <0.001 | |||||
| Married | 15,279 (72.9%) | 15,140 (79.7%) | 17,699 (79.8%) | 15,125 (80.1%) | 14,888 (79.9%) | |
| Not married | 5,624 (26.9%) | 3,819 (20.1%) | 4,445 (20.0%) | 3,723 (19.7%) | 3,729 (20.0%) | |
| Family history of cancer (n, %) | <0.001 | |||||
| No | 9,504 (45.5%) | 8,526 (45.0%) | 9,674 (43.7%) | 8,024 (42.6%) | 7,929 (42.6%) | |
| Yes | 11,370 (54.5%) | 10,420 (55.0%) | 12,445 (56.3%) | 10,815 (57.4%) | 10,665 (57.4%) | |
| Supplemental Beta-Carotene (mcg/day), mean (SD) | 161.8 (338.6) | 173.6 (360.3) | 179.4 (368.0) | 202.4 (386.2) | 208.6 (395.3) | <0.001 |
| Supplemental Calcium (mg/day), mean (SD) | 210.8 (333.1) | 216.3 (332.4) | 244.3 (346.9) | 320.0 (373.1) | 306.8 (373.5) | <0.001 |
| Supplemental Vitamin A (i.u./day), mean (SD) | 2825.0 (3245.7) | 2903.4 (3276.3) | 2961.6 (3259.2) | 3264.6 (3232.1) | 3370.4 (3450.3) | <0.001 |
| Supplemental Vitamin C (mg/day), mean (SD) | 210.7 (354.9) | 220.5 (356.6) | 229.7 (360.9) | 260.4 (377.8) | 279.5 (399.5) | <0.001 |
| Supplemental Vitamin D (mcg/day), mean (SD) | 4.8 (4.8) | 5.0 (4.8) | 5.1 (4.8) | 5.6 (4.7) | 5.7 (4.7) | <0.001 |
| Supplemental Vitamin E (mg/day), mean (SD) | 127.6 (176.4) | 133.1 (171.8) | 140.8 (175.4) | 155.6 (172.5) | 164.3 (180.7) | <0.001 |
PLCO, prostate, lung, colorectal and ovarian; y, year; SD, standard deviation; BMI, body mass index.