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 3 Characteristics by hearing impairment in female 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	2845	379	11.8		2354	870	27.0
Age
20–29	525	7	1.3	< 0.001	519	13	2.4	< 0.001
30–39	535	9	1.7		522	22	4
40–49	676	30	4.2		614	92	13
50–59	641	96	13		479	258	35
60–69	421	196	31.8		209	408	66.1
70–87	47	41	46.6		11	77	87.5
BMI (kg/m²)
Underweight	167	11	6.2	< 0.001	156	22	12.4	< 0.001
Normal	1906	229	10.7		1603	532	24.9
Obese	772	139	15.3		595	316	34.7
Education
≤ Middle school	836	274	24.7	0.031	510	600	54.1	< 0.001
High school	1058	81	7.1		938	201	17.6
≥ College	951	24	2.5		906	69	7.1
Smoking
Non-smoker	2569	358	12.2	0.062	2114	813	27.8	0.004
Ex-smoker	105	8	7.1		88	25	22.1
Current smoker	171	13	7.1		152	32	17.4
Alcohol
None	412	122	22.8	< 0.001	281	253	47.4	< 0.001
Light drinker	1962	243	11		1646	559	25.4
Heavy drinker	471	14	2.9		427	58	12
Exercise
No	2185	315	12.6	0.006	1794	706	28.2	0.003
Yes	660	64	8.8		560	164	22.7
Current diagnosis of diabetes mellitus
No	2717	327	10.7	< 0.001	2272	772	25.4	< 0.001
Yes	128	52	28.9		82	98	54.4
Current diagnosis of hypertension
No	2444	220	8.3	< 0.001	2112	552	20.7	< 0.001
Yes	401	159	28.4		242	318	56.8
Occupational noise exposure
No	2610	348	11.8	0.957	2174	784	26.5	0.043
Yes	235	31	11.7		180	86	32.3
Loud noise exposure
No	2797	375	11.8	0.359	2318	854	26.9	0.535
Yes	48	4	7.7		36	16	30.8
Firearm noise exposure
no	2747	361	11.6	0.200	2288	820	26.4	< 0.001
yes	98	18	15.5		66	50	43.1

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