Table 1

Descriptive statistics of all workers (n = 412)


Smokers (n = 206)
Non-smokers (n = 206)
P value




Mean (SD)
Range
Mean(SD)
Range


Age (year)
42.7(6.2)
24–62
41.4(7.2)
26–67
0.04
Noise exposure duration (year)
18.6(6.6)
2–30
17.1(6.9)
2–32
0.02
Hearing threshold at 4000 Hz (dB)*
34.1(16.4)
0–80
16.4(12.3)
0–65
< 0.001
Smoking (Pack-Year)
13.6(10.6)
0.3–78
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* Better ear

Pouryaghoub et al. BMC Public Health 2007 7:137   doi:10.1186/1471-2458-7-137