Table 3. Adjusted HRs for respiratory diseases associated with a 10-unit increase in the average concentration of air pollutantsa .
| Model description | Category | Number of deaths |
Person-years | SPM (µg/m3) | PM2.5 (µg/m3)b | SO2 (ppb) | NO2 (ppb) | ||||
| HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | ||||
| Sex- and age-adjusted | (All) | 677 | 509 369 | 1.08 | (0.98–1.18) | 1.11 | (0.98–1.27) | 1.38 | (1.23–1.55) | 1.13 | (1.08–1.19) |
| Multivariate modelc | (All) | 677 | 509 369 | 1.11 | (1.03–1.20) | 1.16 | (1.04–1.30) | 1.43 | (1.33–1.54) | 1.16 | (1.12–1.21) |
| By sexe | Male | 417 | 236 047 | 1.07 | (1.00–1.15) | 1.11 | (1.00–1.22) | 1.30 | (1.16–1.47) | 1.11 | (1.05–1.18) |
| Female | 260 | 273 322 | 1.19 | (1.07–1.32) | 1.28 | (1.10–1.49) | 1.68 | (1.40–2.01) | 1.25 | (1.18–1.33) | |
| By sex and smoking statusf |
Male current smokers | 200 | 134 750 | 1.15 | (1.03–1.28) | 1.22 | (1.05–1.42) | 1.52 | (1.35–1.71) | 1.21 | (1.11–1.31) |
| Male former smokers | 130 | 56 849 | 0.89 | (0.79–1.01) | 0.85 | (0.71–1.01) | 0.88 | (0.66–1.18) | 0.90 | (0.80–1.01) | |
| Female never smokers | 218 | 238 431 | 1.19 | (1.09–1.30) | 1.29 | (1.14–1.46) | 1.63 | (1.44–1.84) | 1.25 | (1.20–1.30) | |
| Pneumoniac | (All) | 512 | 509 369 | 1.12 | (1.03–1.21) | 1.17 | (1.04–1.32) | 1.45 | (1.34–1.57) | 1.16 | (1.12–1.21) |
| COPDc | (All) | 64 | 509 369 | 0.92 | (0.78–1.08) | 0.89 | (0.70–1.12) | 1.32 | (0.88–1.98) | 1.03 | (0.93–1.15) |
| Respiratory diseases, using average concentrations during the follow-up periodc,g |
(All) | 677 | 509 369 | 1.08 | (0.89–1.31) | 1.12 | (0.85–1.46) | 1.62 | (1.22–2.15) | 1.14 | (1.06–1.23) |
CI, confidence interval; HR, hazard ratio; NO2, nitrogen dioxide; PM2.5, particulate matter <2.5 µm in aerodynamic diameter; SO2, sulfur dioxide; SPM, suspended particulate matter.
a10-year average concentrations (1974–1983) before the baseline survey were used, unless otherwise specified. 4970 participants with a previous diagnosis of pneumonia, asthma, chronic bronchitis, emphysema, or pneumoconiosis were excluded.
bEstimated by multiplying the level of SPM by 0.7.
cAdjusted for sex, age (continuous), smoking status (current, former, or never), pack-years (0 to <10, 10 to <20, ≥20), smoking status of family members (current smoking/no current smoking), indoor charcoal or briquette braziers used for heating (yes/no), and occupation (experience of occupation with potential exposure to gases, fumes, or dust or not).
eMultivariate model, excluding adjustment for sex. Pack-years were adjusted with different categories for males and females (0 to <10, 10 to <20, 20 to <30, 30 to <40, 40 for males, 0 to <10, 10 to <20, ≥20 for females).
fMultivariate model, excluding adjustment for sex and smoking status. Pack-years was classified into 5 categories for male current and former smokers (0 to <10, 10 to <20, 20 to <30, 30 to <40, ≥40).
gMultivariate model, using the 10-year average concentrations (1984–1993) during the follow-up period.