Incident RA in relation to crops and livestock at enrolment
| Raised for income | Overall sample (applicators and spouses)* | ||
| RA cases n=427 | |||
| N (%) | HR† (95% CI) | P value | |
| Crops only | |||
| ≤62 | 103 (37) | Reference | |
| >62 | 54 (36) | Reference | |
| Animals only | |||
| ≤62 | 5 (1) | 0.83 (0.34 to 2.04) | 0.69 |
| >62 | 2 (0) | NC | – |
| Both | |||
| ≤62 | 148 (35) | 0.68 (0.51 to 0.89) | 0.005 |
| >62 | 80 (19) | 1.08 (0.75 to 1.55) | 0.67 |
| Neither | |||
| ≤62 | 23 (5) | 1.16 (0.73 to 1.85) | 0.53 |
| >62 | 12 (3) | 0.82 (0.43 to 1.56) | 0.54 |
| Crops‡ | |||
| Alfalfa | |||
| ≤62 | 66 (15) | 1.08 (0.80 to 1.49) | 0.57 |
| >62 | 39 (9) | 1.66 (1.10 to 2.50) | 0.015 |
| Field corn | |||
| ≤62 | 203 (48) | 0.92 (0.65 to 1.30) | 0.64 |
| >62 | 112 (26) | 1.65 (1.05 to 2.61) | 0.031 |
| Hay | |||
| ≤62 | 72 (17) | 0.71 (0.53 to 0.93) | 0.014 |
| >62 | 56 (13) | 1.37 (0.97 to 1.92) | 0.074 |
| Oats | 96 (22) | 1.06 (0.31 to 1.35) | 0.64 |
| Soybeans | 289 (68) | 0.98 (0.77 to 1.25) | 0.86 |
| Sweet corn | 45 (11) | 1.25 (0.91 to 1.72) | 0.18 |
| Wheat | 50 (12) | 0.91 (0.66 to 1.26) | 0.56 |
| Livestock† | |||
| Beef cattle | 143 (33) | 0.80 (0.65 to 0.83) | 0.034 |
| Hogs | |||
| ≤62 | 91 (21) | 0.80 (0.60 to 1.06) | 0.12 |
| >62 | 37 (9) | 1.06 (0.70 to 1.59) | 0.79 |
*Numbers shown are for overall sample with complete data on pesticide covariates and diagnosis age, including all enrolled applicators (196 cases and 24 357 non-cases) and spouses (231 cases and 20 842 non-cases).
†HRs and 95% CIs estimated by Cox proportional hazards model adjusting for state, participant type (applicator/spouse), smoking pack-years, education and specific pesticides. HRs allowed to vary by the median age (ie, 62 years) when proportional hazards assumption was not met (p≤0.10).
‡ Common crops or livestock (with at least 10% cases exposed)
RA, rheumatoid arthritis.