Table 1 Demographic characteristics of coke oven workers (COWs) and controls

Age (years)^a

38.1 (7.5)

35.5 (8.3)^*

37.8 (8.2)

BMI (kg/m²)^b

≤25

46 (69)

40 (78)

58 (73)

>25

21 (31)

11 (22)

21 (27)

Level of education^b

 High school and below

57 (85)

46 (90)

73 (92)

 College and above

10 (15)

5 (10)

6 (8)

Cigarette smoking^b

 Nonsmoker

28 (42)

15 (29)

28 (35)

 Smoker

39 (58)

36 (71)

51 (65)

Alcohol drinking^b

 Nondrinker

25 (37)

18 (35)

25 (32)

 Drinker

42 (63)

33 (65)

54 (68)

Working hours per day^a

8.4 (1.1)

7.6 (0.7)

7.7 (0.8)

Years of service^a

10.2 (3.4)

6.9 (2.3)^***

7.6 (1.9)^***