Table 1 Age, employment, hearing, and smoking characteristics of subjects.

	Site A	Site B
All subjects	n = 186	n = 150
Median (range) length of employment prior to audiogram (years)	19 (5–38)	25 (6–40)
Median (range) age at audiogram (years)	57 (45–65)	59 (45–65)
Median (range) of hearing level*, dB	27 (9–81)	25 (1–80)
Smoking, n (% of total)
Never	34 (18%)	24 (16%)
Ex‐smoker	55 (30%)	47 (31%)
Current	97 (52%)	79 (53%)

*Averaged across both ears and frequencies 0.5, 1, 2, 4 kHz.