Table 1

Number, age, gender, smoking habits, and duration of exposure of controls, and moderate and high exposed workers

ControlsModerate exposureHigh exposure
Number7290279
Age, mean (SD)43.4 (9.6)41.1 (10.1) 40.2 (9.7)
Females (%)36.4 5.3 23.2
Smokers (%)31.943.3 50.5
Former smokers (%) 6.918.9 15.4
Never smokers (%)61.137.8 34.1
Exposure (years), mean (SD)16.8 (9.5) 15.6 (8.9)