在中国北方儿童及其家庭中，通过24小时尿碘排泄评估减盐对碘状况的影响：一项整群随机对照试验的子研究
Effect of salt reduction on iodine status assessed by 24 hour urinary iodine excretion in children and their families in northern China: a substudy of a cluster randomised controlled trial.
作者信息
He Feng J, Ma Yuan, Feng Xiangxian, Zhang Wanqi, Lin Laixiang, Guo Xiaohui, Zhang Jing, Niu Wenyi, Wu Yangfeng, MacGregor Graham A
机构信息
Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, London, UK.
Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, London, UK The George Institute for Global Health at Peking University Health Science Center, Beijing, China Department of Epidemiology and Biostatistics, Peking University School of Public Health, Beijing, China.
出版信息
BMJ Open. 2016 Sep 26;6(9):e011168. doi: 10.1136/bmjopen-2016-011168.
OBJECTIVE
To study the effect of salt reduction on iodine status and to determine whether iodine consumption was still adequate after salt reduction in a population where universal salt iodisation is mandatory.
DESIGN
A substudy of a cluster randomised controlled trial, with schools randomly assigned to either the intervention or the control group.
SETTING
28 primary schools in Changzhi, northern China.
PARTICIPANTS
279 children in grade 5 of primary school (mean age: 10.1); 553 adults (age: 43.8).
INTERVENTION
Children were educated about the harmful effects of salt and how to reduce salt intake using the schools' usual health education lessons. Children then delivered the message to their families. The duration was 1 school term (≈3.5 months).
MAIN OUTCOME MEASURE
Difference between the intervention and control groups in the change of iodine intake as measured by repeat 24 hour urinary iodine from baseline to the end of the trial.
RESULTS
At baseline, the mean salt intake was 7.0±2.5 g/day in children and 11.7±4.4 g/day in adults and the median iodine intake was 165.1 μg/day (IQR: 122.6-216.7) and 280.7 μg/day (IQR: 205.1-380.9) in children and adults, respectively. At the end of the study, salt and iodine decreased in the intervention compared with control group. The mean effect on salt for intervention versus control was -1.9 g/day (95% CI -2.6 to -1.3) in children and -2.9 g/day (95% CI -3.7 to -2.2) in adults. The mean effect on iodine was -19.3% (95% CI -29.4% to -7.7%) in children and -11.4% (95% CI -20.3% to -1.5%) in adults.
CONCLUSIONS
With ≈25% reduction in salt intake, there was a significant reduction in iodine consumption in northern China where salt is iodised. Despite this, iodine intake was still adequate, and well above the estimated average requirement. Our findings indicate that reducing salt to the WHO's target-30% reduction by 2025-will not compromise iodine status.
TRIAL REGISTRATION NUMBER
ClinicalTrials.gov NCT01821144.
目的
研究减少食盐摄入量对碘营养状况的影响，并确定在强制实行全民食盐加碘的人群中，减少食盐摄入量后碘摄入量是否仍充足。
设计
一项整群随机对照试验的子研究，学校被随机分配到干预组或对照组。
地点
中国北方长治市的28所小学。
参与者
279名小学五年级儿童（平均年龄：10.1岁）；553名成年人（年龄：43.8岁）。
干预措施
通过学校常规健康教育课程，向儿童传授高盐饮食的危害以及如何减少食盐摄入量。之后儿童将这些信息传达给家人。干预持续时间为1个学期（约3.5个月）。
主要观察指标
通过重复测量从基线到试验结束时24小时尿碘，比较干预组和对照组碘摄入量的变化差异。
结果
基线时，儿童平均食盐摄入量为7.0±2.5克/天，成人为11.7±4.4克/天；儿童和成人的碘摄入量中位数分别为165.1微克/天（四分位间距：122.6 - 216.7）和280.7微克/天（四分位间距：205.1 - 380.9）。研究结束时，与对照组相比，干预组的食盐和碘摄入量均下降。干预组与对照组相比，儿童食盐摄入量平均减少1.9克/天（95%置信区间 -2.6至 -1.3），成人减少2.9克/天（95%置信区间 -3.7至 -2.2）。儿童碘摄入量平均减少19.3%（95%置信区间 -29.4%至 -7.7%），成人减少11.4%（95%置信区间 -20.3%至 -1.5%）。
结论
在中国北方加碘地区，食盐摄入量减少约25%时，碘摄入量显著降低。尽管如此，碘摄入量仍充足，且远高于估计平均需求量。我们的研究结果表明，到2025年将食盐摄入量降至世界卫生组织设定的目标水平（减少30%）不会影响碘营养状况。
试验注册号
ClinicalTrials.gov NCT01821144
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