Table 4.
Associations between driving farm equipment and lung cancer histological subtypes among farmers and female spouses of farmers, Agricultural Health Study.
| Exposure | Farmers | Spouses | ||||||
|---|---|---|---|---|---|---|---|---|
| Adenocarcinoma | Squamous cell carcinoma | Small cell carcinoma | Adenocarcinoma | |||||
| Casesa (n = 78) (n) | RRb (95% CI) | Casesa (n = 75) (n) | RRc (95% CI) | Casesa (n = 50) (n) | RRc (95% CI) | Casesa (n = 69) (n) | RRd (95% CI) | |
| Diesel tractors | ||||||||
| No/< monthly | 7 | 1.00 | 6 | 1.00 | 12 | 1.00 | 47 | 1.00 |
| ≥ Monthly ≥ 1 season | 7 | 1.53 (0.53, 4.40) | 9 | 2.16 (0.76, 6.14) | 18 | 1.00 (0.56, 1.76) | ||
| ≥ Weekly ≥ 1 season | 31 | 1.46 (0.62, 3.45) | 36 | 1.64 (0.66, 4.07) | 24 | 0.98 (0.46, 2.05) | ||
| Daily in one season | 19 | 2.41 (0.94, 6.13) | 12 | 1.36 (0.48, 3.85) | 5 | 0.56 (0.19, 1.70) | ||
| Daily in both seasons | 12 | 3.39 (1.23, 9.33) | 7 | 1.28 (0.40, 4.13) | 7 | 1.16 (0.41, 3.28) | ||
| p for trende | 0.01 | 0.95 | 0.87 | |||||
| Gasoline tractors | ||||||||
| No/< monthly | 24 | 1.00 | 25 | 1.00 | 20 | 1.00 | 49 | 1.00 |
| ≥ Monthly ≥ 1 season | 16 | 0.93 (0.49, 1.77) | 16 | 0.90 (0.48, 1.71) | 8 | 0.59 (0.26, 1.35) | 16 | 1.11 (0.62, 1.99) |
| ≥ Weekly ≥ 1 season | 28 | 1.30 (0.74, 2.29) | 23 | 0.93 (0.52, 1.68) | 11 | 0.61 (0.29, 1.31) | ||
| Daily ≥ 1 season | 8 | 1.51 (0.66, 3.46) | 5 | 0.74 (0.27, 1.98) | 8 | 1.65 (0.69, 3.95) | ||
| p for trende | 0.21 | 0.62 | 0.93 | |||||
| Combines or other types of crop harvesters | ||||||||
| Never | 26 | 1.00 | 18 | 1.00 | 15 | 1.00 | 60 | 1.00 |
| 1–10 days | 11 | 0.76 (0.36, 1.57) | 25 | 2.27 (1.19, 4.34) | 9 | 1.03 (0.43, 2.48) | 8 | 1.29 (0.61, 2.73) |
| 11–30 days | 29 | 1.26 (0.67, 2.35) | 20 | 1.16 (0.56, 2.39) | 17 | 1.40 (0.63, 3.14) | ||
| ≥ 31 days | 10 | 1.01 (0.46, 2.23) | 8 | 1.02 (0.42, 2.50) | 5 | 0.79 (0.27, 2.33) | ||
| p for trende | 0.63 | 0.72 | 0.97 | |||||
| Trucks | ||||||||
| No/< monthly | 24 | 1.00 | 23 | 1.00 | 16 | 1.00 | 47 | 1.00 |
| ≥ Monthly ≥ 1 season | 9 | 0.66 (0.31, 1.43) | 11 | 0.81 (0.39, 1.68) | 9 | 0.90 (0.40, 2.05) | 18 | 0.74 (0.42, 1.29) |
| ≥ Weekly ≥ 1 season | 22 | 1.05 (0.58, 1.90) | 15 | 0.68 (0.35, 1.32) | 13 | 0.75 (0.35, 1.59) | ||
| Daily ≥ 1 season | 19 | 0.94 (0.49, 1.78) | 17 | 0.79 (0.40, 1.54) | 10 | 0.47 (0.21, 1.09) | ||
| p for trende | 0.93 | 0.38 | 0.08 | |||||
| aCase counts do not sum to total case counts because of missing values for exposure variables. bAdjusted for age (< 55, 55–59, 60–64, 65–69, ≥ 70), pack-years (nonsmokers, < 20, 20–39, 40–59, ≥ 60, missing), state, race, level of education (less than high school, high school, above high school, unknown), and current exposure to animals and stored grain (no, one exposure, both exposures). cAdjusted for age (< 55, 55–59, 60–64, 65–69, ≥ 70), pack-years (nonsmokers or < 20, 20–39, 40–59, ≥ 60, missing), state, race, level of education (less than high school, high school, above high school, unknown), and current exposure to animals and stored grain (No, one exposure, both exposures). dAdjusted for age (< 55, 55–59, 60–64, 65–69, ≥ 70), pack-years (nonsmokers, < 20, 20–39, ≥ 40, missing), level of education (high school or less, above high school, unknown), and exposure to farm animals in the year before enrollment. eTest for trend, p-value obtained by treating the categorical variable as ordinal. | ||||||||