Table 6 Relative risks (95 CI) for lung cancer by histological type, from the polytomous logistic regression model 2 comparing risks associated with current and former smoking, Nurses’ Health Study, 1976–2002: final model with corresponding p values for the differences between histological type
Histological type
Squamous cell carcinomaSmall cell carcinomaAdenocarcinomaLarge cell carcinomap Value*
Age (year)1.08 (1.06 to 1.11)1.06 (1.04 to 1.09)1.07 (1.06 to 1.09)1.03 (0.99 to 1.06)0.03
Cigarettes/day (current) (per cig)1.05 (1.04 to 1.06)1.07 (1.06 to 1.09)1.05 (1.04 to 1.06)1.06 (1.04 to 1.07)0.003
Cigarettes/day (former) (per cig)†1.04 (1.04 to 1.05)–––0.59
Duration (per year)1.10 (1.07 to 1.12)1.12 (1.09 to 1.14)1.06 (1.05 to 1.07)1.07 (1.04 to 1.11)<0.001

  • *p Value for test of heterogeneity. †Value in first column is estimated for all histological types combined. –, value from previous column applies.