Table 3.

Demographic, anthropometric, and diet-related parameters and iron status in three categories of infants according to the quartile values of hair mercury content.

Characteristics			Hair Mercury Level (µg/g)		p Value a
		≤0.1 (n = 75)	>0.1 and <0.4 (n = 115)	≥0.4 (n = 62)
Age, months b		11.0 (10.2, 12.0)	11.1 (10.3, 12.35)	11.25 (9.75~12.1)	0.644 c
	Male	42	54	29	0.417
	Female	33	61	33
Gestational age, weeks b		39 (38, 40)	39 (38, 40)	39 (38, 40)	0.241 c
	<37 weeks, n	6	4	2	0.194
Study years, n
	2009/2010	15	55	41	<0.001
	2013/2014	60	60	21
Anthropometry, Z-score d
	Birthweight, kg	3.23 (3.13, 3.33)	3.26 (3.19, 3.33)	3.25 (3.17, 3.34)	0.878 e
	birthweight <2.5 kg, n	6	3	0	0.013
	birthweight	−0.17 (−0.39, 0.05)	−0.08 (−0.24, 0.07)	−0.08 (−0.27, 0.10)	0.743 e
	weight for age	0.67 (0.49, 0.88)	0.49 (0.32, 0.65)	0.39 (0.17. 0.60)	0.142 e
	WAZ-BWZ	0.86 (0.62, 1.10)	0.57 (0.39, 0.75)	0.46 (0.22, 0.70)	0.045 e
	height for age	0.58 (0.32, 0.84)	0.55 (0.33, 0.77)	0.51 (0.23, 0.79)	0.983 e
Dominant feeding method, n
	mostly breastfed	20	74	50	<0.001
	mixed fed	11	14	6
	mostly formula fed	37	24	5
	others	7	3	1
Duration of mostly breastfeeding, months b		0 (0–9)	10 (3.5–11.35)	10.25 (6.3–12.0)	<0.001 c
Fish intake (presence/absence)
	total (n = 241)	35/39	60/49	39/19	0.024
	2009/2010 (n = 100)	7/7	26/23	28/9	0.035
	2013/2014 (n = 141)	28/32	34/26	11/10	0.448
Duration of fish intake, months b
	total	0.0 (0.0, 2.0)	0.0 (0.0, 2.0)	1.0 (0.0, 3.25)	0.033 c
	2009/2010	0.5 (0.0, 3.0)	0.0 (0.0, 2.0)	2.0 (0.0, 4.0)	0.006 c
	2013/2014	0.0 (0.0, 2.0)	1.0 (0.0, 2.0)	1.0 (0.0, 2.0)	0.867 c
Iron status, n
	Deficiency	10	44	29	<0.001
	No deficiency	65	71	33
	Iron deficiency anemia	4	22	13	0.011

^a The values were calculated using the chi-square test, unless otherwise stated; ^b The values are presented as the median and interquartile range; ^c The values were calculated using the Kruskal-Wallis test; ^d The values are presented as the mean and 95% confidence interval; ^e The values were calculated using the ANOVA.