TABLE 3.
ADJUSTED PROPORTIONAL HAZARD MORTALITY RATE RATIOS AND 95% CONFIDENCE INTERVALS FOR A 10-μg/m3 INCREASE IN AVERAGE AMBIENT PM2.5 OVER THE ENTIRE FOLLOW-UP (1974–1998) AND THE RATE RATIOS FOR AVERAGE PM2.5 IN PERIOD 1 AND THE DECREASE IN LEVELS BETWEEN THE TWO PERIODS
| RR (95% CI)
|
||||
|---|---|---|---|---|
| Model 1
|
Model 2
|
|||
| Cases | Entire Follow-Up Average PM2.5† | Period 1 Average PM2.5‡ | Decrease in Average PM2.5‡ | |
| Total mortality | 2,732 | 1.16 (1.07–1.26) | 1.18 (1.09–1.27) | 0.73 (0.57–0.95) |
| Cardiovascular* | 1,196 | 1.28 (1.13–1.44) | 1.28 (1.14–1.43) | 0.69 (0.46–1.01) |
| Respiratory* | 195 | 1.08 (0.79–1.49) | 1.21 (0.89–1.66) | 0.43 (0.16–1.13) |
| Lung cancer* | 226 | 1.27 (0.96–1.69) | 1.20 (0.91–1.58) | 1.06 (0.43–2.62) |
| Other | 1,115 | 1.02 (0.90–1.17) | 1.05 (0.93–1.19) | 0.85 (0.56–1.27) |
For definition of abbreviations, see Table 2.
Rate ratios have been adjusted for age in 1-yr categories, sex, current smoker, current pack-years of smoking, former smoker, former pack-years of smoking, less than high school education, and linear and quadratic terms for body mass index.
Cardiovascular disease (International Classification of Disease, 9th edition [ICD-9] codes 400–440); nonmalignant respiratory disease (ICD-9 codes 485–496); lung cancer (ICD-9 code 162).
Average PM2.5 calculated as the average of Six Cities monitoring data for available years 1980–1988 and PM2.5 estimated from Aerometric Information Retrieval System and extinction data for years where Six Cities data were not available.
Average PM2.5 in Period 1 calculated as the average from 1980–1985, the years where there are monitoring data for all cities, decrease in average PM2.5 (average Period 2 (1990–1998) − average Period 1).