Table 1 Characteristics of the study population at baseline who were current or former smokers, Nurses’ Health Study, 1976–2002*
Histological typeNon-cases
Squamous cell carcinomaSmall cell carcinomaAdenocarcinomaLarge cell carcinoma
No of cases (1976–2002)20123654382
Current smoker before diagnosis115 (57)176 (75)285 (52)49 (60)
Former smoker before diagnosis86 (43)60 (25)258 (48)33 (40)
Age in 1976 (not standardised)47.246.746.845.942.3
Smoking status in 1976 ():
    Former smoker, 1–2 years1.61.51.97.64.6
    Former smoker, >2 years4.12.513.86.636.2
    Current smoker94.296.084.185.857.5
Amount smoked in 1976 among current smokers ():
    <15 cigarettes/day9.24.011.24.228.8
    15–24 cigarettes/day43.243.541.542.344.1
    25–34 cigarettes/day23.229.225.132.417.7
    ⩾35 cigarettes/day24.323.322.221.19.4
Age at start of smoking (mean)18.619.418.918.920.1
    <15 years ()7.42.34.48.42.4
    15–19 years ()54.752.260.942.254.0
    ⩾20 years ()37.945.534.749.543.6
Duration of smoking (years)24.023.422.523.218.6
Pack-years of smoking (mean)31.332.428.732.218.1
Pack-years after age 30 (mean)23.824.621.123.112.0
  • *Values are standardised to the age distribution of the cohort (unless specified). A total of 105 cases occurred in never smokers and are not included in this table.