Table 2.
Hazard Ratios for Ischemic Heart Disease According to Two Categorizations of Recent (within the last year) PM2.5, Each With All Exposures and When Restricted to Exposures Measured with High Confidence, in an Aluminum Manufacturing Cohort in the United States, 1998–2008.
| All Exposures | Only Exposures Assessed with High Confidence | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Categories by Quintiles of Exposure Among Cases | |||||||||
| Recent PM2.5 (mg/m3) | No. cases | Person- years | Hazard Ratiosa | 95% Confidence Interval | Recent PM2.5 (mg/m3) | No. cases | Person- years | Hazard Ratiosa | 95% Confidence Interval |
| ≤ 0.11 | 135 | 11,490 | 1 | ≤ 0.12 | 129 | 10,891 | 1 | ||
| >0.11–0.22 | 143 | 14,272 | 1.05 | 0.81, 1.35 | >0.12–0.23 | 102 | 10,379 | 1.05 | 0.80, 1.39 |
| >0.22–0.45 | 140 | 11,708 | 1.23 | 0.92, 1.63 | >0.23–0.50 | 114 | 10,310 | 1.04 | 0.77, 1.41 |
| >0.45–1.47 | 130 | 11,971 | 1.06 | 0.78, 1.45 | >0.50–1.63 | 109 | 8,899 | 1.29 | 0.88, 1.88 |
| >1.47 | 149 | 14,321 | 1.09 | 0.73, 1.62 | >1.63 | 123 | 11,853 | 1.21 | 0.78, 1.88 |
| Categories by Quartiles of Exposure Among Cases Above Reference Level 0.05mg/m3 | |||||||||
| Recent PM2.5 (mg/m3) | No. cases | Person- years | Hazard Ratiosa | 95% Confidence Interval | Recent PM2.5 (mg/m3) | No. cases | Person- years | Hazard Ratiosa | 95% Confidence Interval |
| ≤ 0.05 | 61 | 6,151 | 1 | ≤ 0.05 | 15 | 1,452 | 1 | ||
| >0.05–0.16 | 156 | 13,770 | 1.26 | 0.92, 1.71 | >0.05–0.16 | 132 | 11,757 | 1.58 | 0.88, 2.63 |
| >0.16–0.34 | 166 | 13,706 | 1.48 | 1.07, 2.05 | >0.16–0.37 | 148 | 12,359 | 1.78 | 1.02, 3.11 |
| >0.34–1.15 | 155 | 14,975 | 1.15 | 0.82, 1.63 | >0.37–1.47 | 139 | 13,074 | 1.48 | 0.83, 2.66 |
| >1.15 | 159 | 15,159 | 1.18 | 0.77, 1.82 | >1.47 | 143 | 13,690 | 1.48 | 0.77, 2.85 |
a
Hazard Ratios adjusted for age, race, gender, calendar year, smoking, facility type, bmi, job grade, and past exposure