Table 2

 Lung function levels (% predicted) in quintile groups for each study

Quintile 1Quintile 2Quintile 3Quintile 4Quintile 5
*Percentage predicted values were calculated using Hankinson’s equation49 with the assumption that the men in the study had a mean height of 170 cm and women had a mean height of 160 cm, and the mean age was 46 years.
Men
    Hole10⩽7374–8788–9798–108>108
    Kuller11*⩽7374–8586–9394–101⩾102
    Mannino12⩽7576–8586–9293–101⩾102
    Van Den Eeden13*⩽6667–7980–9394–104⩾104
Women
    Hole10⩽7475–8990–100101–112⩾113
    Mannino12⩽7778–8788–9495–103⩾103
    Van Den Eeden13*⩽6061–7576–8586–99⩾100