Table 3.
Associations of RA/SLE with personal insecticide use and application by others, stratified by farm history
| Never lived or worked on a farm | Ever lived or worked on a farm | |||||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| 3 year risk RA/SLE |
Cases % |
OS Cohort % |
Adjusted HR* (95% CI) |
3 year risk RA/SLE |
Cases % |
OS Cohort % |
Adjusted HR* (95% CI) |
|
| Personally mixed/applied | ||||||||
| Years | N=124 | N=49,255 | N=57 | N=17,372 | ||||
| Never used insecticides | 0.20 | 26 | 33 | 1.0 | 0.28 | 28 | 33 | 1.0 |
| Never/ < 1 | 0.19 | 22 | 28 | 1.01 (0.53, 1.92) | 0.26 | 19 | 24 | 0.80 (0.30, 2.11) |
| 1-4 | 0.39 | 19 | 12 | 1.92 (1.01, 3.63) | 0.28 | 11 | 12 | 0.74 (0.25, 2.24) |
| 5-19 | 0.25 | 14 | 14 | 1.31 (0.66, 2.57) | 0.41 | 19 | 16 | 1.09 (0.41, 2.88) |
| 20 or more | 0.41 | 12 | 12 | 2.40 (1.33, 4.33) | 0.49 | 23 | 15 | 1.22 (0.49, 3.05) |
| P-value for trend | 0.002 | 0.47 | ||||||
| Times per year | N=124 | N=49,175 | N=56 | N=17,333 | ||||
| Never used insecticides | 0.20 | 26 | 33 | 1.0 | 0.28 | 29 | 33 | 1.0 |
| Never/ < 1 | 0.22 | 25 | 29 | 1.00 (0.53, 1.90) | 0.31 | 23 | 24 | 0.89 (0.34, 2.30) |
| 1-5 | 0.31 | 37 | 30 | 1.91 (1.24, 3.21) | 0.26 | 27 | 33 | 0.72 (0.30, 1.74) |
| 6 or more | 0.40 | 12 | 8 | 2.01 (0.99, 4.08) | 0.71 | 23 | 10 | 1.93 (0.76, 4.90) |
| P-value for trend | 0.003 | 0.43 | ||||||
| Cumulative use | N=125 | N=49,447 | N=57 | N=17,431 | ||||
| Never/very low | 0.21 | 50 | 61 | 1.0 | 0.30 | 51 | 56 | 1.0 |
| Low/moderate | 0.31 | 41 | 33 | 1.85 (1.22, 2.80) | 0.27 | 30 | 37 | 0.80 (0.41, 1.56) |
| High/very high | 0.40 | 10 | 6 | 2.15 (1.08, 4.29) | 0.81 | 19 | 8 | 2.18 (0.96, 4.91) |
| P-value for trend | 0.002 | 0.28 | ||||||
|
| ||||||||
| Others applied | ||||||||
| Years | N=124 | N=49,401 | N=58 | N=17,395 | ||||
| Never used insecticides | 0.20 | 26 | 33 | 1.0 | 0.28 | 28 | 32 | 1.0 |
| Never/ < 1 | 0.38 | 29 | 19 | 1.23 (0.61, 2.46) | 0.25 | 17 | 23 | 0.72 (0.24, 2.21) |
| 1-4 | 0.19 | 12 | 16 | 0.76 (0.31, 1.61) | 0.31 | 14 | 15 | 1.21 (0.42, 3.49) |
| 5-19 | 0.17 | 14 | 21 | 0.64 (0.31, 1.34) | 0.42 | 24 | 19 | 1.77 (0.71, 4.40) |
| 20 or more | 0.43 | 18 | 11 | 1.79 (0.92, 3.46) | 0.54 | 17 | 11 | 2.05 (0.75, 5.55) |
| P-value for trend | 0.73 | 0.028 | ||||||
| Times per year | N=124 | N=49,236 | N=57 | N=17,307 | ||||
| Never used insecticides | 0.20 | 26 | 33 | 1.0 | 0.28 | 28 | 33 | 1.0 |
| Never/ < 1 | 0.40 | 31 | 20 | 1.30 (0.66, 2.58) | 0.25 | 18 | 23 | 0.83 (0.27, 2.51) |
| 1-5 | 0.28 | 40 | 36 | 1.14 (0.63, 2.05) | 0.31 | 32 | 34 | 1.25 (0.52, 3.01) |
| 6 or more | 0.07 | 3 | 11 | 0.34 (0.11, 1.02) | 0.69 | 23 | 11 | 2.95 (1.16, 7.52) |
| P-value for trend | 0.14 | 0.019 | ||||||
| Cumulative use | N=124 | N=49,523 | N=58 | N=17,422 | ||||
| Never/very low | 0.27 | 55 | 52 | 1.0 | 0.27 | 43 | 54 | 1.0 |
| Low/moderate | 0.26 | 43 | 42 | 0.56 (0.57, 1.30) | 0.37 | 45 | 40 | 1.75 (0.91, 3.35) |
| High/very high | 0.09 | 2 | 7 | 0.35 (0.11, 1.13) | 0.63 | 12 | 6 | 2.93 (1.13, 7.64) |
| P-value for trend | 0.10 | 0.017 | ||||||
*
Hazard ratios and 95% confidence intervals estimated from a Cox proportional hazards regression model, adjusted for age (5 year intervals), race/ethnicity, education, occupation, region, pack-years of smoking, BMI, parity, months breastfed, age at menarche, age at menopause, history of asthma, history of other autoimmune disease, history of thyroid disease, modified Charlson index and farm exposure). Models analyzing frequency, duration and cumulative dose of personal use were also adjusted for any application by others, and visa versa.