Table 1. Age-Adjusted Baseline Characteristics of the HPFS, NHS, and NHSII by Quintiles of Sulfur Microbial Diet Score.
| Characteristic | Sulfur microbial diet score, No. (%) | ||||
|---|---|---|---|---|---|
| Quintile 1 (lowest) | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 (highest) | |
| Men (HPFS) | |||||
| No. | 9255 | 9415 | 9349 | 9287 | 9244 |
| Age, mean (SD), ya | 57 (9.8) | 55.8 (9.7) | 54.5 (9.6) | 53.4 (9.4) | 51 (8.9) |
| Race | |||||
| White | 8279 (89.5) | 8491 (90.2) | 8417 (90.0) | 8350 (89.9) | 8380 (90.7) |
| Otherb | 976 (10.5) | 924 (9.8) | 932 (10.0) | 937 (10.1) | 864 (9.3) |
| BMI, mean (SD) | 24.8 (3.3) | 25.3 (3.1) | 25.5 (3.2) | 25.7 (3.3) | 26.1 (3.3) |
| Physical activity, mean (SD), MET h/wk | 28.6 (29.9) | 22.8 (25.5) | 19.7 (23.4) | 17.3 (21.3) | 15.3 (20.7) |
| Smoking statusc | |||||
| Never | 4869 (52.6) | 4571 (48.6) | 4095 (44.8) | 3855 (41.6) | 3372 (36.5) |
| Past | 3641 (39.3) | 3901 (41.4) | 4028 (43.1) | 3913 (42.1) | 3931 (42.5) |
| Current | 375 (4.1) | 569 (6.0) | 789 (8.4) | 1143 (12.3) | 1600 (17.3) |
| Pack-years among ever smokers, mean (SD) | 14.7 (13.7) | 15.8 (14.4) | 16.8 (14.8) | 17.9 (15.3) | 19.4 (15.7) |
| Regular aspirin use | 2687 (29.0) | 2768 (29.4) | 2742 (29.3) | 2700 (29.1) | 2714 (29.4) |
| Regular NSAID use | 761 (8.2) | 895 (9.5) | 1003 (10.7) | 1037 (11.2) | 1072 (11.6) |
| Family history of CRC | 1442 (15.6) | 1420 (15.1) | 1372 (14.7) | 1377 (14.8) | 1283 (13.9) |
| Prior endoscopy | 2726 (29.5) | 2683 (28.5) | 2460 (26.3) | 2226 (24.0) | 2104 (22.8) |
| Prior physical examination | 5712 (61.7) | 5821 (61.8) | 5674 (60.7) | 5437 (58.5) | 5176 (56.0) |
| Total calorie intake, mean (SD), kcal | 2250.7 (624.7) | 2002.5 (589) | 1896.6 (576.8) | 1843.5 (591.1) | 1947.2 (640.9) |
| Western diet pattern score, mean (SD)d | −0.4 (0.8) | −0.2 (0.8) | −0.1 (0.8) | 0.1 (0.9) | 0.5 (1.0) |
| Women (NHS and NHSII) | |||||
| No. | 33 585 | 33 585 | 33 708 | 33 681 | 33 688 |
| Age, mean (SD), ya | 44.3 (9.8) | 43.6 (9.5) | 43.1 (9.2) | 42.5 (8.9) | 41.6 (8.4) |
| Race | |||||
| White | 31 941 (95.1) | 32 127 (95.7) | 32 225 (95.6) | 32 225 (95.8) | 32 276 (95.8) |
| Otherb | 1644 (4.9) | 1458 (4.3) | 1483 (4.4) | 1456 (4.3) | 1412 (4.2) |
| BMI, mean (SD) | 24.1 (4.5) | 24.2 (4.5) | 24.4 (4.6) | 24.6 (4.9) | 25.2 (5.4) |
| Physical activity, mean (SD), MET h/wk | 26.6 (31.8) | 20.3 (24.1) | 17.8 (22.2) | 15.6 (20.9) | 13.4 (18.9) |
| Smoking statusc | |||||
| Never | 19 892 (59.2) | 19 578 (58.3) | 19 200 (57.0) | 18 293 (54.3) | 16 683 (49.6) |
| Past | 10 129 (30.2) | 9574 (28.5) | 8964 (26.6) | 8339 (24.8) | 7589 (22.5) |
| Current | 3502 (10.4) | 4359 (13.0) | 5507 (16.3) | 7011 (20.8) | 9371 (27.8) |
| Pack-years among ever smokers, mean (SD) | 21.8 (17.1) | 23.8 (18.3) | 24.4 (18.9) | 26.1 (19.1) | 28.0 (19.8) |
| Regular aspirin use | 11 552 (34.4) | 12 415 (37.0) | 12 996 (38.6) | 13 466 (40.0) | 13 787 (40.9) |
| Regular NSAID use | 7480 (22.3) | 7987 (23.8) | 8323 (24.7) | 8450 (25.1) | 9195 (27.3) |
| Family history of CRC | 4319 (12.9) | 4220 (12.6) | 4257 (12.6) | 4237 (12.6) | 4016 (11.9) |
| Prior endoscopy | 2330 (6.9) | 2112 (6.3) | 2025 (6.0) | 1949 (5.8) | 1762 (5.2) |
| Prior physical examination | 28 467 (84.8) | 27 899 (83.1) | 27 628 (82.0) | 27 028 (80.2) | 25 915 (76.9) |
| Total calorie intake, mean (SD), kcal | 2049.1 (527.6) | 1816.9 (497.6) | 1704.9 (504.4) | 1616.2 (510.3) | 1666.2 (555.7) |
| Western diet pattern score, mean (SD)d | −0.3 (0.9) | −0.2 (0.9) | −0.1 (0.9) | 0 (0.9) | 0.5 (1.1) |
| Menopausal hormone therapy | |||||
| Premenopausal | 23 971 (71.4) | 24 112 (71.9) | 24 099 (71.4) | 24 077 (71.5) | 24 236 (72.0) |
| Never used hormones | 4910 (14.6) | 4881 (14.5) | 5142 (15.3) | 5269 (15.6) | 5294 (15.7) |
| Past hormone user | 1971 (5.9) | 1957 (5.8) | 1977 (5.9) | 1907 (5.7) | 1969 (5.8) |
| Current hormone user | 2733 (8.1) | 2635 (7.8) | 2490 (7.4) | 2428 (7.2) | 2189 (6.5) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CRC, colorectal cancer; HPFS, Health Professionals Follow-up Study; MET, metabolic equivalent task; NHS, Nurses’ Health Study; NHSII, Nurses’ Health Study II; NSAID, nonsteroidal anti-inflammatory drug.
a
Not adjusted for age.
b
Includes American Indian/Native American, Asian, Black, Hawaiian, and multiracial.
c
Percentages do not add up to 100% owing to missing data (3.8%-4.0% in men and 0.1%-0.2% in women), which were categorized into a missing category.
d
The predefined Western dietary pattern score was derived from principal component analysis.