Andersen Stig, Noahsen Paneeraq, Westergaard Louise, Laurberg Peter
1Arctic Health Research Centre,Institute of Clinical Medicine,Aalborg University Hospital,9000 Aalborg,Denmark.
2Department of Geriatric and Internal Medicine,Aalborg University Hospital,9000 Aalborg,Denmark.
Br J Nutr. 2017 Feb;117(3):441-449. doi: 10.1017/S0007114517000162. Epub 2017 Feb 22.
The occurrence of thyroid disorders relies on I nutrition and monitoring of all populations is recommended. Measuring I in urine is standard but thyroglobulin in serum is an alternative. This led us to assess the reliability of studies using serum thyroglobulin compared with urinary I to assess the I nutrition level and calculate the number of participants needed in a study with repeated data sampling in the same individuals for 1 year. Diet, supplement use and life style factors were assessed by questionnaires. We measured thyroglobulin and thyroglobulin antibodies in serum and I in urine. Participants were thirty-three Caucasians and sixty-four Inuit living in Greenland aged 30-49 years. Serum thyroglobulin decreased with rising I excretion (Kendall's τ -0·29, P=0·005) and did not differ with ethnicity. Variation in individuals was lower for serum-thyroglobulin than for urinary I (mean individual CV: 15·1 v. 46·1 %; P<0·01). It required 245 urine samples to be 95 % certain of having a urinary I excretion within 10 % of the true mean of the population. For serum-thyroglobulin the same precision required 206 samples. In an individual ten times more samples were needed to depict I deficiency when using urinary I excretion compared with serum-thyroglobulin. In conclusion, more participants are need to portray I deficiency in a population when using urinary I compared with serum-thyroglobulin, and about ten times more samples are needed in an individual. Adding serum-thyroglobulin to urinary I may inform surveys of I nutrition by allowing subgroup analysis with similar reliability.
甲状腺疾病的发生与碘营养状况有关，建议对所有人群进行监测。测量尿碘是标准方法，但血清甲状腺球蛋白是一种替代方法。这促使我们评估使用血清甲状腺球蛋白与尿碘来评估碘营养水平的研究的可靠性，并计算在对同一人群进行为期1年的重复数据采样的研究中所需的参与者数量。通过问卷调查评估饮食、补充剂使用和生活方式因素。我们测量了血清中的甲状腺球蛋白和甲状腺球蛋白抗体以及尿碘。参与者为33名居住在格陵兰的30至49岁的白种人和64名因纽特人。血清甲状腺球蛋白随尿碘排泄量的增加而降低（肯德尔氏τ=-0·29，P=0·005），且与种族无关。血清甲状腺球蛋白的个体差异低于尿碘（个体平均变异系数：15·1%对46·1%；P<0·01）。需要245份尿样才能有95%的把握使尿碘排泄量在人群真实平均值的10%范围内。对于血清甲状腺球蛋白，达到相同精度需要206份样本。与血清甲状腺球蛋白相比，在个体中使用尿碘排泄量来描述碘缺乏时所需的样本量要多10倍。总之，与血清甲状腺球蛋白相比，使用尿碘来描述人群中的碘缺乏需要更多的参与者，且在个体中所需样本量大约多10倍。将血清甲状腺球蛋白与尿碘结合使用，通过进行具有相似可靠性的亚组分析，可能有助于碘营养调查。
