Table 1

Baseline characteristics of NPC subjects at randomization

VariableTotal NPC n = 1312Valid baseline selenium n = 1250Valid baseline selenium
Selenium supplemented group n = 621Placebo supplemented group n = 629
Gender, males (%)981 (74.8)934 (75.0)461 (74.0)473 (75.0)
Age, mean (SD)63.2 (10.1)63.2 (10.0)63.1 (10.2)63.3 (9.9)
Years of follow-up (PY)7.9 (2.6)7.9 (2.6)8.0 (2.5)7.8 (2.6)
Baseline plasma selenium, ng/ml, mean (SD)114.9 (23.0)114.2 (22.0)114.0 (22.6)114.4 (21.5)
Baseline smoking status, n (%)
 Current375 (28.6)355 (28.4)166 (26.7)189 (30.1)
 Former514 (39.2)497 (39.8)246 (39.6)251 (39.9)
 Never423 (32.2)398 (31.8)209 (33.7)189 (30.1)
Age at smoking initiation, mean (SD)a17.8 (6.2)17.7 (6.1)18.0 (6.4)17.5 (5.8)
Years smoked, mean (SD)a45.0 (11.1)45.0 (11.1)44.9 (11.2)45.2 (11.0)
Cigarettes/day, mean (SD)a24.7 (15.7)24.9 (15.8)25.0 (16.3)24.9 (15.3)
Pack years, mean (SD)a56.0 (39.4)56.6 (39.6)56.8 (40.4)56.5 (38.9)
Alcoholic drinks/week, mean (SD)b13.0 (20.6)12.9 (20.5)11.9 (19.4)13.8 (21.5)
  • a Calculated excluding never-smokers.

  • b Calculated excluding nondrinkers.