Table 4.
Rheumatoid Arthritis Association With Broadcast Pesticides Sprayed From Trucks or Airplanes Before 1975, Sister Study, United States, 2004–2009
| Times Exposed to Broadcast Spraysa | No Lifetime Farm Residence | Child-Only Farm Residence | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Case Patients With RA (n = 284) | Noncase Patients (n = 35,761) | Age Adjusted | Case Patients With RA (n = 84) | Noncase Patients (n = 7,036) | Age Adjusted | |||||||
| No. | % | No. | % | OR | 95% CI | No. | % | No. | % | OR | 95% CI | |
| None | 252 | 89 | 30,371 | 85 | 1.0 | Referent | 66 | 79 | 5,740 | 84 | 1.0 | Referent |
| No more than the median | 12 | 4 | 3,042 | 8 | 0.53 | 0.30, 0.95 | 2 | 2 | 546 | 8 | NCb | |
| More than the median | 20 | 7 | 2,358 | 7 | 1.0 | 0.66, 1.7 | 15 | 18 | 580 | 8 | 2.3 | 1.3, 4.1 |
Abbreviations: CI, confidence intervals; NC, not calculated; OR, odds ratio; RA, rheumatoid arthritis.
a Median split based on distribution in noncase patients with 6 episodes before 1975. There were missing data on 10 noncase patients (0%) with no lifetime farm residence and on 1 case patient (1%) and 170 noncase patients (2%) with childhood-only farm residence.
b Not calculated because there were fewer than 3 exposed cases.