Table 3.
Intensity weighted lifetime days of pesticide use and risk of specialist-confirmed RA among AHS applicators with ≥ 24 months continuous FFS Medicare coverage (1999–2016).
| IWLD categories 1 | Non-cases | Cases2 | Relative Risk |
|---|---|---|---|
| (N = 22,084) N (%) |
(N = 161) N (%) |
(95% CI) 3 | |
| Insecticides | |||
| Organochlorine | |||
| DDT* | |||
| None | 6161 (63) | 46 (60) | Reference |
| M1 | 1784 (18) | 16 (21) | 1.01 (0.57–1.80) |
| M2 | 1796 (18) | 15 (19) | 0.85 (0.47–1.54) |
| p-trend | 0.63 | ||
| Organophosphate | |||
| Chlorpyrifos | |||
| None | 10,333 (56) | 72 (56) | Reference |
| M1 | 3999 (22) | 24 (19) | 0.92 (0.58–1.45) |
| M2 | 3990 (22) | 32 (25) | 1.23 (0.81–1.86) |
| p-trend | 0.42 | ||
| Malathion* | |||
| None | 3193 (31) | 22 (*) | Reference |
| T1 | 2418 (23) | < 11 | 0.55 (0.25–1.25) |
| T2 | 2370 (23) | 18 (*) | 1.19 (0.64–2.24) |
| T3 | 2378 (23) | 28 (*) | 1.67 (0.95–2.94) |
| p-trend | 0.03 | ||
| Terbufos | |||
| None | 10,886 (61) | 75 (63) | Reference |
| M1 | 3437 (19) | 18 (15) | 0.97 (0.57–1.64) |
| M2 | 3429 (19) | 27 (23) | 1.39 (0.89–2.18) |
| p-trend | 0.19 | ||
| Carbamates | |||
| Carbaryl* | |||
| None | 5205 (49) | 31 (38) | Reference |
| T1 | 1803 (17) | 18 (22) | 1.75 (0.97–3.16) |
| T2 | 1810 (17) | 15 (18) | 1.35 (0.71–2.58) |
| T3 | 1802 (17) | 18 (22) | 1.36 (0.69–2.69) |
| p-trend | 0.34 | ||
| Carbofuran | |||
| None | 11,958 (68) | 75 (61) | Reference |
| M1 | 2827 (16) | 20 (16) | 1.26 (0.77–2.08) |
| M2 | 2824 (16) | 27 (22) | 1.53 (0.99–2.37) |
| p-trend | 0.05 | ||
| Herbicides | |||
| Anilids/anilines | |||
| Alachlor | |||
| None | 7700 (43) | 51 (41) | Reference |
| T1 | 3334 (19) | 22 (18) | 1.18 (0.71–1.96) |
| T2 | 3346 (19) | 28 (23) | 1.45 (0.91–2.30) |
| T3 | 3342 (19) | 23 (19) | 1.11 (0.68–1.81) |
| p-trend | 0.38 | ||
| Metolachlor | |||
| None | 9493 (54) | 59 (46) | Reference |
| T1 | 2742 (15) | 26 (20) | 1.87 (1.17-3.00) |
| T2 | 2747 (16) | 19 (15) | 1.38 (0.82–2.33) |
| T3 | 2725 (15) | 23 (18) | 1.60 (0.98–2.59) |
| p-trend | 0.04 | ||
| Pendimethalin* | |||
| None | 6270 (61) | 52 (*) | Reference |
| M1 | 1996 (19) | < 11 | 0.47 (0.21–1.04) |
| M2 | 1991 (19) | 19 (*) | 1.18 (0.70-2.00) |
| p-trend | 0.92 | ||
| Trifluralin | |||
| None | 8003 (45) | 56 (46) | Reference |
| T1 | 3237 (18) | 19 (16) | 1.06 (0.62–1.80) |
| T2 | 3214 (18) | 21 (17) | 1.27 (0.75–2.14) |
| T3 | 3240 (18) | 25 (21) | 1.46 (0.89–2.38) |
| p-trend | 0.12 | ||
| Phenoxy | |||
| 2,4-D | |||
| None | 4034 (21) | 32 (23) | Reference |
| Q1 | 3870 (20) | 29 (21) | 1.07 (0.65–1.78) |
| Q2 | 3878 (20) | 23 (17) | 0.92 (0.53–1.60) |
| Q3 | 3878 (20) | 23 (17) | 0.92 (0.53–1.61) |
| Q4 | 3866 (20) | 30 (22) | 1.19 (0.71-2.00) |
| p-trend | 0.71 | ||
| Thiocarbamate | |||
| Butylate* | |||
| None | 7051 (73) | 54 (*) | Reference |
| M1 | 1327 (14) | < 11 | 0.52 (0.20–1.33) |
| M2 | 1315 (14) | 17 (*) | 1.74 (0.97–3.11) |
| p-trend | 0.16 | ||
| Triazine/Triazinone | |||
| Atrazine | |||
| None | 5027 (26) | 31 (23) | Reference |
| Q1 | 3506 (18) | 23 (17) | 1.20 (0.69–2.11) |
| Q2 | 3513 (18) | 26 (20) | 1.34 (0.77–2.33) |
| Q3 | 3507 (18) | 25 (19) | 1.30 (0.74–2.28) |
| Q4 | 3506 (18) | 27 (20) | 1.33 (0.76–2.32) |
| p-trend | 0.31 | ||
| Cyanazine | |||
| None | 10,157 (57) | 77 (61) | Reference |
| M1 | 3827 (21) | 25 (20) | 1.18 (0.73–1.92) |
| M2 | 3825 (21) | 25 (20) | 1.19 (0.74–1.94) |
| p-trend | 0.43 | ||
| Metribuzin* | |||
| None | 6061 (61) | 48 (*) | Reference |
| M1 | 1926 (19) | 20 (*) | 1.82 (1.03–3.21) |
| M2 | 1946 (20) | < 11 | 0.89 (0.44–1.80) |
| p-trend | 0.83 | ||
| Other | |||
| Dicamba | |||
| None | 8472 (48) | 72 (56) | Reference |
| T1 | 3069 (17) | 22 (17) | 1.21 (0.71–2.06) |
| T2 | 3055 (17) | 19 (15) | 1.06 (0.61–1.86) |
| T3 | 3067 (17) | 16 (12) | 0.89 (0.49–1.60) |
| p-trend | 0.75 | ||
| Glyphosate | |||
| None | 4031 (21) | 30 (21) | Reference |
| Q1 | 3857 (20) | 24 (17) | 0.84 (0.49–1.45) |
| Q2 | 3856 (20) | 22 (16) | 0.77 (0.44–1.34) |
| Q3 | 3857 (20) | 28 (20) | 0.99 (0.59–1.67) |
| Q4 | 3844 (20) | 37 (26) | 1.27 (0.77–2.08) |
| p-trend | 0.25 | ||
| Imazethapyr | |||
| None | 10,811 (60) | 83 (66) | Reference |
| M1 | 3645 (20) | 25 (20) | 1.27 (0.75–2.13) |
| M2 | 3648 (20) | 17 (14) | 0.92 (0.51–1.64) |
| p-trend | 0.92 | ||
1As reported in 1993-97 and updated 1999–2003. Scores are grouped based on percent exposed cases: median (30 < 50%), tertiles (50 < 70%), or quartiles (≥ 70%) as intensity-weighted lifetime days (IWLD) use of specific pesticides up through enrollment (1993–1997) or first follow-up (1999–2003) prior to RA diagnosis; *Enrollment IWLD based on the take home questionnaire.
2Among participants with ≥ 24 months continuous fee for service (FFS) coverage (Parts A and B without Part C), including an initial ≥ 12-month clean period with no RA claims; specialist-confirmed cases had ≥ 2 claims for RA ≥ 30 days apart, plus ≥ 1 claim from a rheumatologist. Asterix (*) indicates percent not shown if number or percent not shown due to < 11 in a cell or ability to infer the count of groups with < 11 exposed cases.
3Relative Risk (RR) and 95% Confidence Intervals (CI) calculated using log binomial regression. Models adjust for categorical age at enrollment (40–49, 50–59, 60–69, 70+), state (NC, IA) state, (NC, IA)-education (≤ high school, > high school), smoking pack years, and correlated pesticides (R2 > 0.350) [aldicarb (chlorothalonil and benomyl)-chlorothalonil (aldicarb and benomyl)-atrazine (alachlor)-butylate (cyanazine and metribuzin)].