HRs and 95% CIs by exposure surrogate*
| Outcome | Exposed-days (all), referent 2500 days | Fire-runs (CFD, PFD), referent 2100 runs | Fire-hours (CFD), referent 600 h | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Model† | Cases | HR (95% CI) at 8700 days | Model† | Cases | HR (95% CI) at 8800 runs | Model† | Cases | HR (95% CI) at 2300 h | |
| Mortality | |||||||||
| All cancers | III | 1333 | 0.95 (0.90 to 0.99) | III | 1162 | 0.95 (0.89 to 1.01) | III | 810 | 0.97 (0.90 to 1.05) |
| MN colorectal | V | 144 | 0.65 (0.46 to 0.95) | I | 124 | 0.58 (0.42 to 0.80) | II | 92 | 0.63 (NC to 0.93) |
| MN oesophagus | II | 61 | 0.61 (NC to 1.10) | III | 54 | 1.24 (0.91 to 1.88) | III | 34 | 1.18 (0.80 to 1.98) |
| MN lung | III | 429 | 0.93 (0.86 to 1.03) | I | 398 | 1.11 (0.95 to 1.29) | I | 288 | 1.39 (1.12 to 1.73) |
| MN prostate | II | 85 | 0.73 (0.52 to 1.14) | II | 69 | 0.71 (NC to 0.90) | II | 58 | 0.61 (NC to 0.92) |
| NHL | III | 53 | 1.30 (0.93 to 2.06) | I | 47 | 0.70 (0.42 to 1.10) | II | 29 | 0.54 (NC to 1.08) |
| Leukaemia | I | 52 | 1.38 (0.75 to 2.64) | III | 45 | 1.45 (1.00 to 2.35) | III | 31 | 1.32 (0.87 to 2.36) |
| IHD | II | 914 | 0.73 (0.63 to 0.84) | I | 822 | 0.89 (0.79 to 1.00) | II | 581 | 0.90 (0.76 to 1.08) |
| CeVD | V | 124 | 1.05 (0.67 to 1.72) | IV | 113 | 1.18 (0.75 to 1.89) | II | 79 | 0.79 (0.53 to 1.32) |
| Cirrhosis | I | 99 | 0.76 (0.46 to 1.29) | I | 87 | 0.72 (0.48 to 1.05) | III | 56 | 0.93 (0.74 to 1.22) |
| COPD | I | 130 | 0.83 (0.59 to 1.19) | II | 113 | 0.93 (0.73 to 1.26) | IV | 84 | 1.47 (0.86 to 2.59) |
| Incidence | |||||||||
| All cancers | V | 2609 | 0.96 (0.87 to 1.05) | I | 2197 | 1.01 (0.95 to 1.08) | I | 1395 | 1.01 (0.92 to 1.12) |
| MN colorectal | III | 289 | 0.92 (0.84 to 1.01) | I | 240 | 0.89 (0.72 to 1.09) | II | 158 | 0.78 (0.63 to 1.04) |
| MN oesophagus | II | 54 | 0.66 (0.42 to 1.18) | III | 48 | 1.22 (0.89 to 1.88) | II | 29 | 0.57 (NC to 1.85) |
| MN lung | I | 382 | 1.05 (0.84 to 1.33) | I | 358 | 1.10 (0.94 to 1.28) | I | 243 | 1.39 (1.10 to 1.74) |
| MN prostate | V | 832 | 0.90 (0.77 to 1.05) | I | 678 | 1.02 (0.91 to 1.14) | III | 419 | 0.98 (0.90 to 1.09) |
| NHL | III | 92 | 1.07 (0.92 to 1.28) | II | 79 | 0.79 (0.64 to 1.10) | III | 45 | 1.12 (0.89 to 1.50) |
| Leukaemia | V | 58 | 0.99 (0.56 to 1.89) | II | 49 | 1.08 (0.75 to 1.84) | III | 33 | 0.90 (0.68 to 1.30) |
| MN bladder | III | 174 | 1.01 (0.89 to 1.19) | III | 144 | 1.05 (0.89 to 1.27) | III | 95 | 0.98 (0.79 to 1.27) |
*Results adjusted for race, fire department and birth cohort. The exposure lag used for NHL and leukaemia was 5 years; all others lagged 10 years.
†Model forms for H(Dβ): I, exp(Dβ); II, 1+Dβ; III, (1+D)β; IV, exp(Dβ1+D2β2); V, RCS (3 knots). Where H is the hazard rate, D is cumulative dose and βi represents parameters to be estimated. Hazard rate ratios shown for the best fitting model based on smallest AIC value.
AIC, Akaike Information Criterion; CeVD, cerebrovascular disease; CFD, Chicago Fire Department; COPD, chronic obstructive pulmonary disease; IHD, ischaemic heart disease; MN, malignant neoplasm; NC, not calculable; NHL, non-Hodgkin's lymphoma; PFD, Philadelphia Fire Department; RCS, restricted cubic spline.