Table 4

Association between variables in exposure to noise and a notch at 4 and 6 kHz

Type of exposure to noise	No notch	4 kHz^4-150	OR	95% CI	6 kHz^4-151	OR	95% CI	6 kHz both ears	OR	95% CI
Continuous:
Low	103	6	1.00	Reference	63	1.00	Reference	28	1.00	Reference
Medium	54	5	1.65	0.49 to 5.54	32	0.97	0.57 to 1.66	12	0.82	0.39 to 1.73
High	31	3	1.90	0.46 to 7.87	15	0.79	0.40 to 1.58	5	0.59	0.21 to 1.67
Impulse:
None	27	1	1.00	Reference	13	1.00	Reference	6	1.00	Reference
Protected	27	4	4.00	0.43 to 37.17	12	0.92	0.36 to 2.38	7	1.17	0.35 to 3.92
Unprotected	134	9	1.65	0.20 to 13.33	85	1.32	0.64 to 2.69	32	1.07	0.41 to 2.82
Firearms:
Never exposed	118	4	1.00	Reference	79	1.00	Reference	28	1.00	Reference
Ever exposed	70	10	4.77	1.46 to 15.53	31	0.66	0.40 to 1.10	17	1.02	0.52 to 2.00
Explosion:
Never exposed	164	11	1.00	Reference	95	1.00	Reference	36	1.00	Reference
Ever exposed	24	3	1.68	0.45 to 6.23	15	1.08	0.54 to 2.16	9	1.71	0.73 to 3.98

↵4-150 A 4 kHz notch present in either or both ears.
↵4-151 A 6 kHz notch present in either ear.