Table 1. Selected characteristics of the subjects by stove use history in Xuanwei, 1976–1996: n (%) or means (95% CI).
Change to stove with chimney
|
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---|---|---|---|
Yes (n=12 529) | No (n=9127) | Total (n=21 701) | |
Person-years | 242 154 | 159 831 | 401 985 |
Age on 1 January, 1976, years | 38.8 (38.6–39.0) | 40.4 (40.2–40.6) | 39.5 (39.3–39.6) |
Age at exit from follow-up, years | 58.1 (57.9–58.3) | 57.8 (57.6–58.0) | 58.0 (57.9–58.1) |
Lung cancer deaths, 1976–1996 | 706 (5.6) | 527 (5.7) | 1233 (5.7) |
Age at lung cancer death | 56.7 (56.1–57.3) | 53.9 (53.2–54.7) | 55.5 (55.0–56.0) |
People who ever used smoky coal | 11 319 (90.3) | 3795 (41.4) | 15 114 (69.6) |
Tons per year | 3.44 (3.42–3.46) | 2.88 (2.84–2.91) | 3.30 (3.28–3.31) |
Age at stove improvement | 41.8 (41.6–42.0) | ||
Years from stove improvement to exit from follow-up | 16.3 (16.2–16.4) | ||
Ever smoked | 11 658 (93.0) | 8352 (91.1) | 20 010 (92.2) |
Age started smoking | 21.5 (21.4–21.5) | 20.7 (20.6–20.8) | 21.1 (21.1–21.2) |
Years of smoking among smokers | 33.3 (33.2–33.5) | 34.3 (34.1–34.5) | 33.8 (33.6–33.9) |
Ever quit smoking | 173 (1.4) | 89 (1.0) | 262 (1.2) |
Abbreviation: CI=confidence interval.