Table 5 Relative risks (RR; 95 CI) for lung cancer by histological type, from the polytomous logistic regression model 1 comparing risks associated with current and former smoking, Nurses’ Health Study, 1976–2002: relative risks corresponding with 5, 10 and 15 years since quitting smoking*
Histological typeYears since quitting
5 years10 years15 years
Squamous cell carcinoma0.57 (0.50 to 0.63)0.32 (0.25 to 0.41)0.18 (0.13 to 0.26)
Small cell carcinoma0.40 (0.34 to 0.47)0.16 (0.11 to 0.22)0.06 (0.04 to 0.10)
Adenocarcinoma0.67 (0.62 to 0.72)0.45 (0.39 to 0.52)0.30 (0.24 to 0.38)
Large cell carcinoma0.63 (0.53 to 0.75)0.40 (0.28 to 0.56)0.25 (0.15 to 0.42)
  • *Age, age at smoking initiation and cigarettes smoked per day included in the model.