School of Agriculture Food and Wine, Faculty of Sciences, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
Department of Human Nutrition, Institute of Public Health, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
Public Health Nutr. 2019 Nov;22(16):3063-3072. doi: 10.1017/S1368980019001915.
The present study aimed to evaluate the effect of mandatory iodine fortification of bread on the iodine status of South Australian populations using newborn thyroid-stimulating hormone (TSH) concentration as a marker.
The study used an interrupted time-series design.
TSH data collected between 2005 and 2016 (n 211 033) were extracted from the routine newborn screening programme in South Australia for analysis. Iodine deficiency is indicated when more than 3 % of newborns have TSH > 5 mIU/l.
Newborns were classified into three groups: the pre-fortification group (those born before October 2009); the transition group (born between October 2009 and June 2010); and the post-fortification group (born after June 2010).
The percentage of newborns with TSH > 5 mIU/l was 5·1, 6·2 and 4·6 % in the pre-fortification, transition and post-fortification groups, respectively. Based on a segmented regression model, newborns in the post-fortification period had a 10 % lower risk of having TSH > 5 mIU/l than newborns in the pre-fortification group (incidence rate ratio (IRR) = 0·90; 95 % CI 0·87, 0·94), while newborns in the transitional period had a 22 % higher risk of having TSH > 5 mIU/l compared with newborns in the pre-fortification period (IRR = 1·22; 95 % CI 1·13, 1·31).
Using TSH as a marker, South Australia would be classified as mild iodine deficiency post-fortification in contrast to iodine sufficiency using median urinary iodine concentration as a population marker. Re-evaluation of the current TSH criteria to define iodine status in populations is warranted in this context.
本研究旨在利用新生儿促甲状腺激素（TSH）浓度作为标志物，评估强制性面包加碘对南澳大利亚人群碘营养状况的影响。
本研究采用了中断时间序列设计。
从南澳大利亚常规新生儿筛查计划中提取了 2005 年至 2016 年（n=211033）的 TSH 数据进行分析。当超过 3%的新生儿 TSH>5mIU/L 时，即表明存在碘缺乏。
将新生儿分为三组：加碘前组（2009 年 10 月前出生）；过渡组（2009 年 10 月至 2010 年 6 月出生）；加碘后组（2010 年 6 月后出生）。
加碘前、过渡和加碘后组的 TSH>5mIU/L 的新生儿百分比分别为 5.1%、6.2%和 4.6%。基于分段回归模型，加碘后组新生儿 TSH>5mIU/L 的风险比加碘前组降低 10%（发病率比（IRR）=0.90；95%CI 0.87，0.94），而过渡组新生儿 TSH>5mIU/L 的风险比加碘前组高 22%（IRR=1.22；95%CI 1.13，1.31）。
与使用中位数尿碘浓度作为人群标志物的碘充足相比，使用 TSH 作为标志物，南澳大利亚在加碘后将被归类为轻度碘缺乏。在这种情况下，有必要重新评估当前 TSH 标准来定义人群的碘营养状况。
