Table 1.
Age-standardized characteristics of participants according to cumulative pack-years smoked in the NHS (1980-2014) and the HPFS (1986-2014)
| Characteristica | Women (NHS) |
Men (HPFS) |
||||||
|---|---|---|---|---|---|---|---|---|
| Cumulative pack-years smoked |
Cumulative pack-years smoked |
|||||||
| 0 | 1-19 | 20-39 | ≥40 | 0 | 1-19 | 20-39 | ≥40 | |
| (n = 38 062) | (n = 26 603) | (n = 15 649) | (n = 6043) | (n = 21 193) | (n = 10 387) | (n = 8277) | (n = 4930) | |
| Mean age (SD), y | 61.7 (11.9) | 60.2 (11.9) | 60.5 (11.4) | 64.8 (9.8) | 63.9 (11.5) | 63.9 (11.3) | 66.0 (11.1) | 68.9 (9.8) |
| Family history of colorectal cancer, % | 13.6 | 13.8 | 13.8 | 12.9 | 12.7 | 12.5 | 12.7 | 12.3 |
| Mean BMI (SD), kg/m² | 25.5 (4.7) | 25.2 (4.6) | 25.2 (4.5) | 25.1 (4.4) | 25.6 (3.4) | 25.7 (3.1) | 26.3 (3.6) | 26.4 (3.6) |
| Postmenopausal status, % | 77.5 | 76.8 | 80.5 | 88.0 | — | — | — | — |
| Menopausal hormone therapy, % | 26.4 | 27.9 | 24.3 | 20.9 | — | — | — | — |
| History of colonoscopy/sigmoidoscopy, % | 41.5 | 44.7 | 39.9 | 36.2 | 56.0 | 57.7 | 53.8 | 49.0 |
| Regular use of aspirin, % | 34.2 | 35.0 | 36.4 | 37.2 | 46.1 | 49.0 | 49.6 | 50.6 |
| Regular use of other NSAIDs, % | 35.0 | 38.1 | 38.4 | 34.4 | 16.2 | 19.1 | 17.8 | 16.9 |
| Physical activity, mean (SD), METS-h/wk | 16.6 (16.8) | 18.1 (18.7) | 16.8 (17.7) | 13.3 (14.4) | 29.3 (24.7) | 29.6 (24) | 26.1 (22.7) | 20.7 (20.1) |
| Alcohol intake, mean (SD), g/d | 3.8 (6.9) | 6.9 (8.9) | 8.0 (10.6) | 9.9 (13.3) | 8.0 (11.1) | 12.5 (13.8) | 14.3 (15.8) | 16.6 (18.7) |
| Red and processed meat intake, mean (SD), servings/wk | 6.6 (3.7) | 6.3 (3.5) | 6.6 (3.6) | 7.1 (3.7) | 6.1 (4.3) | 6.1 (4.2) | 6.8 (4.6) | 7.9 (5.1) |
| Total folate intake, mean (SD), μg/d | 432 (212) | 442 (213) | 413 (204) | 389 (208) | 552 (253) | 563 (256) | 524 (251) | 494 (246) |
All variables other than age were standardized to age distribution of each cohort. Mean (SD) for continuous variables or percentages for categorical variables are presented. BMI = body mass index; HPFS = Health Professionals Follow-up Study; METS = metabolic equivalent task score; NHS = Nurses’ Health Study; NSAID = nonsteroidal anti-inflammatory drug.