Variations in the Urinary Iodine Concentration and Urinary Iodine/Creatinine Ratio among Preschool Children

Table 2

UIC, UCr, and UI/Cr in preschool children according to collection time within one day.

Time	n	UIC (μg/L)		n	UCr (g/L)		n	UI/Cr ratio (μg/g)
8:00 am∼10:00 am	142	84.79 (40.61, 136.45)	<0.001	136	0.30 (0.19, 0.43)	<0.001	136	287.74 (181.35, 515.23)	0.019
10:00 am∼12:00 pm	142	21.49 (11.61, 57.29)		136	0.07 (0.03, 0.19)		136	332.58 (157.76, 511.84)
12:00 pm∼3:00 pm	148	27.51 (12.62, 59.92)		141	0.09 (0.04, 0.14)		141	347.67 (168.71, 635.06)
3:00 pm∼6:00 pm	142	41.22 (21.30, 83.62)		133	0.12 (0.05, 0.23)		133	394.72 (217.42, 670.50)

UIC, urinary iodine concentration, UCr, urinary creatinine concentration, UI/Cr, urinary iodine/creatinine ratio. Values are medians (interquartile ranges). Differences between repeated spot urine collections were compared using the Friedman nonparametric hypothesis test.