Study on the rhythm of urine iodine level of children aged 8-10 in Chongqing city / 中国地方病学杂志

ABSTRACT

Objective To undemtand the rhythm of urinary iodine level of children aged 8-10 in Chongqing city.Methods In April 2008,using the stratified random sampling method,we sampled 60 children aged 8-10 in a lodging primary school in Chongqing(20 per age group,half male and half female),the urine samples were collected in the morning and at 1000,1230,1600,iodine in urine was detected by method of Ce and arsenic catalytic speetrophotometry(WS/T 107-2006).The difference of the urinary iodine level was compared by age,sex and time of day.Results The median urinary iodine of 60 children was 265.07μg/L on the overall.Irrespective of the stratification factors,excluding morning urinary iodine(366.75μg/L)and urinary iodine at 1000(338.30 μg/L),the urinary iodine between 1230(235.15μg/L)and 1600(251.50μg/L)was not significant(all P>0.05),statistically significant differences(all P<0.05)were found between any two.The urinary iodine of 8-year-old group at different times of the day was significantly different(all P<0.05),except between morning urinary iodine (298.90 μg/L)and at 1000,1600(279.00,286.59 μg/L),between urinary iodine at 1000 and 1600(all P>0.05).The 9-year-old group's urinary iodine were not significantly different between morning urine(366.15μg/L)and 1000(368.10 μg/L),and between 1230(244.00 μg/L)and 1600(186.30 μg/L,all P>0.05),significant differences were faund at other times of the day(all P<0.05).The 10-year-old group of urinary iodine changed very little before 1230 (382.85,449.60,337.00 μg/L, all P > 0.05 ), followed by rapid decline to 16 00 (269.35 μg/L), and compared with the morning urine and 1000, there was significant difference(all P < 0.05).Regardless boys or girls, the urinary iodine at different times qf the day was significantly different (all P < 0.05),except between morning urinary iodine(337.32,309.28 μg/L) and at 1000(316.15,288.27 μg/L), between urinary iodine at 1230(251.18,211.45 μg/L) and 1600(235.02,211.45 μg/L, all P > 0.05). Conclusions The change of urinary iodine level in children aged 8 - 10 was not obvious before noon, changes can be seen in the afternoon.Urinary iodine level before 1000 is indicative.