Table 2 Demographic data on 60 male cement factory workers categorized into groups with high and low dust exposure

Age (years)^a

28.5 (8.2)

39.7 (7.9)

< 0.0005^c

Height(m)^a

1.72 (0.075)

1.72 (0.048)

0.988^c

Employment (years)^a

6.8 (5)

9 (7)

0.124^c

Primary education only^b

7 (17.5)

6 (30)

0.326^d

Current smokers^b

4 (10)

2 (10)

1.000^d

Non smokers^b

36(90)

18(90)

1.000^d

Ex-smokers^b

4(11)

2(11)

1.000^d

Past respiratory diseases

0(0)

0(0)

1.000^d