Table 1.
Evaluation of the imputation method used in the glyphosate and cancer analysis in the Agricultural Health Study: cancer incidence by completion of the follow-up questionnaire, and the estimated number of cases affected by alternative imputation method
| Glyphosate use* | Exposure reported at enrollment and at follow-up (all subjects, using completed and imputed data) |
Exposure reported at enrollment only (all subjects) |
Exposure reported at enrollment and at follow-up (only subjects with completed follow-up questionnaire) |
Exposure reported at enrollment and imputed at follow-up (only subjects without follow-up questionnaire) |
Pinteraction† | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of cases | RR (95%CI)† | Ptrend† | No. of cases | RR (95%CI)† | Ptrend† | No. of cases | RR (95%CI)† | Ptrend† | No. of cases | RR (95%CI)† | Ptrend† | ||
| All cancer | |||||||||||||
| None | 1511 | 1.00 | 1954 | 1.00 | 918 | 1.00 | 593 | 1.00 | |||||
| Q1 | 1445 | 0.99 (0.91 to 1.07) | 1338 | 0.99 (0.92 to 1.06) | 897 | 0.98 (0.89 to 1.09) | 548 | 1.01 (0.88 to 1.15) | |||||
| Q2 | 1443 | 0.99 (0.91 to 1.07) | 1339 | 0.99 (0.92 to 1.07) | 999 | 1.03 (0.93 to 1.13) | 444 | 0.93 (0.81 to 1.07) | |||||
| Q3 | 1440 | 1.04 (0.96 to 1.13) | 1328 | 1.03 (0.95 to 1.11) | 950 | 1.01 (0.91 to 1.12) | 490 | 1.14 (0.99 to 1.31) | |||||
| Q4 | 1451 | 0.99 (0.91 to 1.08) | .91 | 1325 | 0.97 (0.90 to 1.05) | .74 | 1012 | 1.01 (0.91 to 1.12) | .66 | 439 | 0.97 (0.84 to 1.12) | .70 | .73 |
| Affected cases‡ | — | — | — | — | — | — | — | — | — | 5 | — | — | — |
| Non-Hodgkin lymphoma | |||||||||||||
| None | 135 | 1.00 | 159 | 1.00 | 81 | 1.00 | 54 | 1.00 | |||||
| Q1 | 113 | 0.83 (0.59 to 1.18) | 116 | 0.98 (0.76 to 1.25) | 67 | 0.75 (0.52 to 1.07) | 46 | 0.86 (0.55 to 1.36) | |||||
| Q2 | 104 | 0.83 (0.61 to 1.12) | 91 | 0.75 (0.57 to 0.98) | 74 | 0.83 (0.59 to 1.18) | 30 | 0.67 (0.41 to 1.10) | |||||
| Q3 | 112 | 0.88 (0.65 to 1.19) | 108 | 0.98 (0.75 to 1.28) | 79 | 0.88 (0.62 to 1.25) | 33 | 0.89 (0.54 to 1.44) | |||||
| Q4 | 111 | 0.87 (0.64 to 1.20) | .95 | 98 | 0.82 (0.62 to 1.80) | .82 | 86 | 0.90 (0.63 to 1.27) | .54 | 25 | 0.59 (0.34 to 1.03) | .10 | .58 |
| Affected cases‡ | — | — | — | — | — | — | — | — | — | 3 | — | — | — |
| Multiple myeloma | |||||||||||||
| None | 30 | 1.00 | 32 | 1.00 | 19 | 1.00 | 11 | 1.00 | |||||
| Q1 | 19 | 0.70 (0.36 to 1.36) | 19 | 0.85 (0.47 to 1.53) | 11 | 0.57 (0.26 to 1.27) | 8 | 1.02 (0.33 to 3.12) | |||||
| Q2 | 26 | 0.94 (0.50 to 1.76) | 20 | 0.87 (0.49 to 1.57) | 18 | 0.89 (0.44 to 1.81) | 8 | 1.24 (0.41 to 3.74) | |||||
| Q3 | 19 | 0.78 (0.39 to 1.56) | 26 | 1.23 (0.70 to 2.16) | 15 | 0.80 (0.38 to 1.68) | 4 | 0.79 (0.22 to 2.92) | |||||
| Q4 | 24 | 0.87 (0.45 to 1.69) | .84 | 18 | 0.73 (0.39 to 1.38) | .76 | 20 | 1.00 (0.49 to 2.05) | .66 | 4 | 0.54 (0.13 to 2.32) | .42 | .65 |
| Affected cases‡ | — | — | — | — | — | — | — | — | — | 1 | — | — | — |
| Acute myeloid leukemia | |||||||||||||
| None | 9 | 1.00 | 10 | 1.00 | 3 | 1.00 | 6 | 1.00 | |||||
| Q1 | 13 | 1.62 (0.60 to 4.38) | 14 | 2.25 (0.96 to 5.27) | 8 | 2.65 (0.69 to 10.18) | 5 | 1.01 (0.30 to 3.41) | |||||
| Q2 | 14 | 1.70 (0.61 to 4.73) | 10 | 1.64 (0.65 to 4.13) | 8 | 2.24 (0.56 to 8.95) | 6 | 1.29 (0.40 to 4.18) | |||||
| Q3 | 12 | 1.46 (0.49 to 4.37) | 15 | 2.70 (1.14 to 6.43) | 7 | 2.01 (0.48 to 8.41) | 5 | 0.98 (0.26 to 3.72) | |||||
| Q4 | 18 | 2.44 (0.94 to 6.32) | .11 | 17 | 2.62 (1.14 to 6.07) | .03 | 12 | 3.87 (1.02 to 14.75) | .09 | 6 | 1.54 (0.44 to 5.32) | .55 | .79 |
| Affected cases‡ | — | — | — | — | — | — | — | — | — | 1 | — | — | — |
Quartiles of intensity weighted days of glyphosate use: Q1 = 1–598.9, Q2 = 599–1649.9, Q3 = 1650–4339.9, Q4 = ≥4340.0.
Poisson regression was used to model rate ratios (RR) and 95% confidence intervals (CI). Ptrend was calculated using a two-sided Wald test. Pinteraction was calculated using the log-likelihood ratio test for the interaction between completion of the follow-up questionnaire and glyphosate use. All models adjusted for age, state of recruitment, education, cigarette smoking status, alcohol per month, family history of cancer, atrazine, alachlor, metolachlor, trifluralin, 2, 4-D.
Estimated number of cases that would change exposure status from never to ever or vice versa among participants who did not complete the follow-up questionnaire. Affected cases are based on the mean absolute difference in the predicted probabilities from the logistic regression models with and without the designated cancer outcome (see Supplementary Table 1).