Table 3.
Field work and other farm exposures in relation to incident RA cases for female spouses in the Agricultural Health Study.
| Tasks and other farm exposures | Incident cases | ||
|---|---|---|---|
| Noncases n= 24,018 n (%) | Cases n = 132 n (%) | OR (95% CI)a | |
| Worked in the field recent growing season | |||
| No | 11,132 (48) | 71 (55) | 1.0 (referent) |
| < 10 days | 4,766 (20) | 22 (17) | 0.78 (0.48, 1.3) |
| 10–30 days | 4,183 (18) | 23 (18) | 0.89 (0.55, 1.4) |
| > 30 days | 3,235 (14) | 13 (10) | 0.63 (0.35, 1.4) |
| Tasksb | |||
| Till soil | 5,740 (25) | 27 (22) | 0.88 (0.57, 1.4) |
| Planting | 5,538 (24) | 40 (32) | 1.3 (0.91, 2.0) |
| Apply natural fertilizer | 2,700 (12) | 13 (11) | 0.85 (0.48, 1.5) |
| Apply chemical fertilizer | 2,540 (11) | 23 (18) | 1.7 (1.1, 2.7) |
| Drive combines | 2,545 (11) | 11 (9) | 0.86 (0.46, 1.6) |
| Handpick crops | 5,909 (25) | 37 (29) | 1.1 (0.75, 1.7) |
| Other tasks, at least monthlyb | |||
| Drive trucks | 8,942 (39) | 42 (35) | 0.88 (0.59, 1.3) |
| Drive diesel tractor | 7,727 (34) | 33 (27) | 0.77 (0.49, 1.1) |
| Drive gas tractor | 5,956 (26) | 32 (26) | 1.0 (0.65, 1.5) |
| Clean with gasoline | 3,440 (15) | 18 (15) | 1.0 (0.61, 1.7) |
| Clean with solvents | 4,522 (20) | 33 (27) | 1.6 (1.1, 2.4) |
| Painting | 7,246 (32) | 45 (37) | 1.3 (0.91, 1.9) |
| Veterinary procedures | 2,927 (13) | 13 (11) | 0.99 (0.55, 1.8) |
| Hours per day in the sun, recent growing season | |||
| < 1 | 4,678 (26) | 32 (29) | 1.0 (referent) |
| 1 to 2 | 5,769 (33) | 42 (39) | 1.1 (0.72, 1.8) |
| 3 to 5 | 5,047 (29) | 26 (24) | 0.82 (0.49, 1.4) |
| ≥ 6 | 2,127 (12) | 9 (8) | 0.67 (0.32, 1.4) |
| Hours per day in the sun, 10 years ago | |||
| < 1 | 2,940 (18) | 13 (14) | 1.0 (referent) |
| 1 to 2 | 4,391 (26) | 30 (28) | 1.4 (0.75, 2.6) |
| 3 to 5 | 5,724 (35) | 44 (42) | 1.6 (0.86, 2.8) |
| ≥ 6 | 3,506 (21) | 16 (15) | 0.89 (0.44, 1.8) |
| Regular livestock contact, past 12 monthsc | |||
| Never | 10,820 (46) | 60 (54) | 1.0 (referent) |
| Infrequent | 6,765 (29) | 35 (27) | 0.99 (0.65, 1.5) |
| Frequent | 5,699 (24) | 24 (19) | 0.82 (0.51, 1.3) |
| Livestock exposure, in childhoodc | |||
| None | 4,752 (27) | 33 (29) | 1.0 (referent) |
| Infrequent | 2,469 (14) | 13 (11) | 0.81 (0.42, 1.6) |
| Frequent | 10,589 (59) | 68 (60) | 0.87 (0.57, 1.3) |
| Any childhood and current livestock exposure | |||
| Neither | 3,754 (21) | 28 (25) | 1.0 (referent) |
| Childhood only | 9,256 (52) | 70 (61) | 0.96 (0.62, 1.5) |
| Current only | 998 (6) | 5 (4) | 0.84 (0.32, 2.2) |
| Childhood and current | 3,802 (21) | 11 (10) | 0.48 (0.24, 0.97) |
| aLogistic regression models adjusted for age, state and pack-years smoking, estimated ORs and 95% CI. bReferent group was an answer of “no” for each task. cInfrequent is less than once per week, and frequent is at least weekly. | |||