Environmental exposure of heavy metal (lead and cadmium) and hearing loss: data from the Korea National Health and Nutrition Examination Survey (KNHANES 2010–2013)

Table 2 Characteristics by hearing impairment in male subjects

Variables	Low frequency hearing impairment				High frequency hearing impairment
Variables	Normal^a	Impaired^a	Rate^b	p-value^c	Normal^a	Impaired^a	Rate^b	p -value^c
Total	2743	442	13.9		1697	1488	46.7
Age
20–29	486	7	1.4	< 0.001	466	27	5.5	< 0.001
30–39	525	12	2.2		455	82	15.3
40–49	680	29	4.1		444	265	37.4
50–59	601	116	16.2		244	473	66
60–69	406	209	34		84	531	86.3
70–87	45	69	60.5		4	110	96.5
BMI (kg/m²)
Underweight	56	12	17.6	0.086	39	29	42.6	0.610
Normal	1650	286	14.8		1020	916	47.3
Obese	1037	144	12.2		638	543	46
Education
≤ Middle school	514	237	31.6	< 0.001	159	592	78.8	< 0.001
High school	1086	140	11.4		691	535	43.6
≥ College	1143	65	5.4		847	361	29.9
Smoking
Non-smoker	664	59	8.2	< 0.001	483	240	33.2	< 0.001
Ex-smoker	860	203	19.1		426	637	59.9
Current smoker	1219	180	12.9		788	611	43.7
Alcohol
None	77	27	26	< 0.001	42	62	59.6	< 0.001
Light drinker	1613	310	16.1		914	1009	52.5
Heavy drinker	1053	105	9.1		741	417	36
Exercise
No	1941	330	14.5	0.093	1195	1076	47.4	0.239
Yes	802	112	12.3		502	412	45.1
Current diagnosis of diabetes mellitus
No	2558	378	12.9	< 0.001	1639	1297	44.2	< 0.001
Yes	185	64	25.7		58	191	76.7
Current diagnosis of hypertension
No	2289	284	11	< 0.001	1528	1045	40.6	< 0.001
Yes	454	158	25.8		169	443	72.4
Occupational noise exposure
no	2222	316	12.5	< 0.001	1413	1125	44.3	< 0.001
yes	521	126	19.5		284	363	56.1
Loud noise exposure
no	2667	428	13.8	0.640	1645	1450	46.8	0.386
yes	76	14	15.6		52	38	42.2
Firearm noise exposure
no	1425	217	13.2	0.265	884	758	46.2	0.517
yes	1318	225	14.6		813	730	47.3

ISSN: 2052-4374