Table 3. The distribution of hearing thresholds at different frequencies in the ONID and control groups.

Groups	0.5 kHz	1.0 kHz	2.0 kHz	3.0 kHz	4.0 kHz	6.0 kHz
ONID group (n = 150)	24.20±7.97	30.82±9.11	42.93±12.80	56.60±13.33	63.57±13.74	67.97±16.41
Control group (n = 150)	14.07±5.78	15.60±5.05	15.57±5.26	16.53±5.37	17.17±4.86	17.53±4.63
t	12.229	17.450	23.549	34.412	38.774	37.080
P value	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001

ONID, occupational noise-induced deafness.