Study | Population | Sample size | Women(%) | Age(years) | Current smokers (%) | Outcome, n | Years of follow up | Comparison | Adjusted factors |
---|---|---|---|---|---|---|---|---|---|

SD, standard deviation; FEV_{1}, forced expiratory volume in 1 second; RR, relative risk; NR, not reported; IPPB, Intermittent Positive Pressure Breathing Trial; JHLP, Johns Hopkins Lung Project. | |||||||||

*Relative risk and 95% confidence interval. | |||||||||

†Ratio of FEV_{1} to standing height^{3}. | |||||||||

‡RR was derived by comparison of the ratios (observed/expected) in different groups. Expected deaths were determined using log rank method. | |||||||||

¶Respiratory cancer. | |||||||||

Islam^{15} | Tecumseh Community population in Detroit | 3956 | 53.1 | ⩾25 | 43.9 | Incidence, 77 | 25 | Predictor: FEV_{1}% pred | Age, sex, smoking history |

Every 1 unit decrease of FEV_{1}% pred, regression coefficient 0.016 | |||||||||

p = 0.017 | |||||||||

Nomura^{16} | Japanese-American men on Hawaiian island of Oahu | 6317 | 0 | ⩾45 | 47.0 | Incidence, 172 | 22 | Predictor: FEV_{1}% pred quartile | Age, detailed smoking information |

Quartile 3 v 4: RR = 1.0 (0.6 to 1.9)^{*} | |||||||||

Quartile 2 v 4: RR = 2.5 (1.5 to 4.1)^{*} | |||||||||

Quartile 1 v 4: RR = 2.1 (1.3 to 3.5)^{*} | |||||||||

Speizer^{17} | Random sample of community white adults from six US cities | 8427 | 54.8 | 25–74 | 39.8 | Mortality, 61 | 9–12 | Predictor: FEV_{1} quartile | |

Quartile 3 v 4: RR = 3.99 | |||||||||

Quartile 2 v 4: RR = 2.00 | |||||||||

Quartile 1 v 4: RR = 8.27 | |||||||||

Vestbo^{18} | Random sample of all men in Aalborg, Denmark | 876 | 0 | ⩾46 | NR | Incidence¶, 35 | 11 | Predictor: FEV_{1}%/H^{3}† | Age, smoking status |

Per litre below expected FEV_{1} given height: | |||||||||

RR = 2.1 (1.3 to 3.4)^{*} | |||||||||

Lange^{8} | Random sample of general population in Copenhagen | 13946 | 54.3 | ⩾20 | 63.0 | Mortality, 225 | 10 | Predictor: FEV_{1}% pred | Age, sex, smoking history, chronic phlegm. |

40–79% v ⩾80%: | |||||||||

RR = 2.1 (1.3 to 3.4)^{*} | |||||||||

<40 v ⩾80: | |||||||||

RR = 3.9 (2.2 to 7.2)^{*} | |||||||||

Tockman ^{7} | White American men including a sample of patients with moderate to severe obstruction from the IPPB Trial and cigarette smoking volunteers from JHLP | IPPB: 667 JHLP: 3728 | 0 | ⩾45 | NR | Mortality,IPPB: 22 JHLP: 41 | IPPB: 3.0 JHLP: 1.2 | Predictor: FEV_{1}% pred IPPB:<60% v ⩾60%:RR = 4.85, p = 0.002 JHLP:60–85% v >85%:RR = 2.57, p = 0.043<60% v >85%:RR = 2.72, p = 0.062 | Age, pack-years, bronchitis, shortness of breath |

Peto^{19} | Random sample of men from the Vale of Glamorgan and employees in two UK institutions | 2718 | 0 | 30–64 | NR | Mortality, 103 | 20–25 | Predictor: FEV_{1}%/H^{3}† | Stratified by age group and area |

0–1 SD below averagev >average:RR = 2.17‡ | |||||||||

1–2 SD below averagev >average:RR = 2.02‡ | |||||||||

>2 SD below averagev >average:RR = 1.89‡ | |||||||||

Wiles^{20} | Random sample of male gold miners in South Africa | 2065 | 0 | 45–54 | NR | Mortality, 74 | 16–18 | Predictor: FEV_{1}/H^{3}† | Stratified by age group |

0–1 SD below averagev >average:RR = 1.69‡ | |||||||||

1–2 SD below averagev >average:RR = 2.65‡ | |||||||||

>2 SD below averagev >average:RR = 2.87‡ |