Table 1.

Basic Information Distribution in Case and Control Groups

Variables	Case (n = 292)	Control (n = 584)	Statistics	p
Age, year
20~30	45 (15.4%)	104 (17.8%)
30~40	79 (27.1%)	153 (26.2%)
40~50	134 (45.9%)	270 (46.2%)
50~60	34 (11.6%)	57(9.8%)	1.381‡	0.710
Noise exposure duration, year	18.860 (8.500, 27.750)	18.509 (8.167, 26.917)	−0.692§	0.489
CNE, dB(A)*	97.844 (94.686, 101.522)	97.767 (94.854, 101.195)	−0.153§	0.878
HTL, dB(A) †	50.980 (44.042, 55.833)	18.293 (12.500, 24.000)	−24.153§	<0.001
Height, cm	170.366 (167.000, 174.750)	169.993 (166.000, 174.000)	−1.004§	0.315
Gender
Male	281 (96.2%)	560 (95.9%)
Female	11 (3.8%)	24 (4.1%)	0.060‡	0.807
level of environmental noise exposure, dB(A)
≤ 85	121 (41.4%)	254 (43.5%)
> 85	171 (58.6%)	330 (56.5%)	0.336‡	0.562
Tinnitus
Yes	196 (67.4%)	316 (54.2%)
No	95 (32.6%)	267 (45.8%)	12.837‡	<0.001
Smoking
Yes	181 (62.0%)	341 (58.4%)
No	109 (38.0%)	243 (41.6%)	1.045‡	0.307
Drinking
Yes	203 (69.5%)	399 (68.3%)
No	89 (30.5%)	185 (31.7%)	0.130‡	0.718
Hypertension
Yes	112 (38.4%)	242 (41.4%)
No	180 (61.6%)	342 (58.6%)	0.768‡	0.381

Evaluation of the matching effects in the case and control groups by comparing the basic information distribution between them

^*CNE: cumulative noise exposure

^†HTL: the binaural average hearing threshold level in high frequencies

^‡Pearson chi-square test

^§Wilcoxon rank sum test