Table 3.
Impact of smoking amount on COPD development.
| Sex | Smoking amount, Pack-year | N | Event | Duration | IR, per 1,000 PY | HR (95% CI) | ||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model 1 | Model 2 | Model 3 | ||||||||||||||||||||||||||||||
| Total | Non | 3,485,089 | 6,627 | 28963394.53 | 0.2288 | 1 (Ref.) | 1 (Ref.) | 1 (Ref.) | <10 | 1,849,834 | 3,889 | 15455833.55 | 0.2516 | 1.099 (1.056–1.143) | 1.266 (1.206–1.328) | 1.264 (1.205–1.327) | 10 ≤ … < 20 | 803,870 | 2,416 | 6845253.4 | 0.3530 | 1.537 (1.467–1.610) | 1.548 (1.461–1.639) | 1.539 (1.453–1.631) | ≥20 | 168,783 | 857 | 1435172.42 | 0.5971 | 2.599 (2.421–2.791) | 2.236 (2.062–2.425) | 2.209 (2.037–2.396) |
| Male* | Non | 1,148,534 | 2,192 | 9605130.78 | 0.2282 | 1 (Ref.) | 1 (Ref.) | 1 (Ref.) | <10 | 1,623,329 | 3,294 | 13626880.68 | 0.2417 | 1.059 (1.003–1.117) | 1.177 (1.113–1.244) | 1.175 (1.112–1.242) | 10 ≤ … < 20 | 795,199 | 2,370 | 6776623.49 | 0.3497 | 1.528 (1.441–1.619) | 1.456 (1.370–1.547) | 1.450 (1.365–1.541) | ≥20 | 167,821 | 849 | 1427663.97 | 0.5947 | 2.597 (2.399–2.811) | 2.067 (1.899–2.249) | 2.049 (1.883–2.231) |
| Female* | Non | 2,336,555 | 4,435 | 19358263.75 | 0.2291 | 1 (Ref.) | 1 (Ref.) | 1 (Ref.) | <10 | 226,505 | 595 | 1828952.87 | 0.3253 | 1.426 (1.309–1.553) | 1.508 (1.380–1.648) | 1.506 (1.378–1.646) | 10 ≤ … < 20 | 8,671 | 46 | 68629.92 | 0.6703 | 2.946 (2.204–3.940) | 2.346 (1.749–3.146) | 2.320 (1.730–3.112) | ≥20 | 962 | 8 | 7508.44 | 1.0655 | 4.696 (2.347–9.394) | 3.265 (1.627–6.552) | 3.193 (1.591–6.408) |
Model 1, non-adjusted; Model 2, adjusted for age, sex, BMI, alcohol consumption, regular exercise, income, pneumonia, asthma; Model 3, adjusted for age, sex, BMI, alcohol consumption, regular exercise, income, pneumonia, asthma, diabetes mellitus, hypertension, dyslipidemia. *Sex was excluded from multivariate models. COPD, chronic obstructive pulmonary disease; IR, incidence rate; PY, person-year; HR, hazard ratio; CI, confidence interval; Ref., reference.