Population correlates of circulating mercury levels in Korean adults: the Korea National Health and Nutrition Examination Survey IV

Table 2 Demographic characteristics of participants from the KNHANES (2008–2009), according to quartile of blood mercury levels (n = 3972)

	Geometric mean of mercury	N	Quartile of blood mercury level
			Q1 (0.88-3.06)	Q2 (3.07-4.36)	Q3 (4.37-6.41)	Q4 (6.42-56.97)	p-value
	(μg/L)		%	%	%	%
Age (years)							<0.001
20-29	3.81	775	26	21	19	11
30-39	4.48	795	18	23	21	19
40-49	5.04	800	15	19	20	27
50-59	5.15	790	14	18	22	25
≥60	4.15	812	27	19	18	18
Men	5.35	1994	32	41	57	72	<0.001
Overweight/obesity (BMI ≥ 23)	5.13	1242	25	27	32	42	<0.001
Smoking status							<0.001
Never	3.99	2126	68	61	49	37
Former	5.22	807	14	17	21	29
Current	5.14	1033	18	22	30	34
Alcohol intake (≥1/week)	5.68	938	13	17	26	38	<0.001
Eating-out (≥1/day)	4.88	713	17	21	24	27	<0.001
MET-h/week							0.003
<20	4.29	1693	48	43	42	39
20-39	4.60	763	19	20	19	20
≥40	4.69	1493	33	37	39	41
Income level							<0.001
Low	4.14	1004	30	27	24	22
Mid low	4.45	968	24	26	25	23
Mid high	4.43	965	26	26	23	24
High	5.06	964	20	21	28	31
Education							<0.001
Middle school or less	4.36	1340	39	31	33	33
High school	4.38	1490	37	42	38	34
College or more	4.82	1125	24	27	29	33
Residence area							<0.001
Midwest	3.67	475	18	12	11	7
North	4.23	1873	51	51	48	38
Southwest	4.48	504	13	12	13	13
Mideast	5.36	422	8	10	10	14
Southeast and an island	5.52	698	10	15	18	28

ISSN: 1471-2458