Department of Endocrinology, Royal Free Hampstead NHS Trust, London, UK.
Lancet. 2011 Jun 11;377(9782):2007-12. doi: 10.1016/S0140-6736(11)60693-4. Epub 2011 Jun 2.
Iodine deficiency is the most common cause of preventable mental impairment worldwide. It is defined by WHO as mild if the population median urinary iodine excretion is 50-99 μg/L, moderate if 20-49 μg/L, and severe if less than 20 μg/L. No contemporary data are available for the UK, which has no programme of food or salt iodination. We aimed to assess the current iodine status of the UK population.
In this cross-sectional survey, we systematically assessed iodine status in schoolgirls aged 14-15 years attending secondary school in nine UK centres. Urinary iodine concentrations and tap water iodine concentrations were measured in June-July, 2009, and November-December, 2009. Ethnic origin, postcode, and a validated diet questionnaire assessing sources of iodine were recorded.
810 participants provided 737 urine samples. Data for dietary habits and iodine status were available for 664 participants. Median urinary iodine excretion was 80·1 μg/L (IQR 56·9-109·0). Urinary iodine measurements indicative of mild iodine deficiency were present in 51% (n=379) of participants, moderate deficiency in 16% (n=120), and severe deficiency in 1% (n=8). Prevalence of iodine deficiency was highest in Belfast (85%, n=135). Tap water iodine concentrations were low or undetectable and were not positively associated with urinary iodine concentrations. Multivariable general linear model analysis confirmed independent associations between low urinary iodine excretion and sampling in summer (p<0·0001), UK geographical location (p<0·0001), low intake of milk (p=0·03), and high intake of eggs (p=0·02).
Our findings suggest that the UK is iodine deficient. Since developing fetuses are the most susceptible to adverse effects of iodine deficiency and even mild perturbations of maternal and fetal thyroid function have an effect on neurodevelopment, these findings are of potential major public health importance. This study has drawn attention to an urgent need for a comprehensive investigation of UK iodine status and implementation of evidence-based recommendations for iodine supplementation.
Clinical Endocrinology Trust.
碘缺乏是全世界最常见的可预防智力障碍原因。世界卫生组织将人群中位数尿碘排泄量在 50-99μg/L 时定义为轻度碘缺乏，20-49μg/L 时定义为中度，小于 20μg/L 时定义为重度。英国没有食物或盐碘化方案，因此没有当代数据。我们旨在评估英国人口的当前碘状况。
在这项横断面研究中，我们系统性地评估了在英国 9 个中心的中学就读的 14-15 岁女学生的碘状况。2009 年 6-7 月和 11-12 月期间测量了尿碘浓度和自来水碘浓度。记录了种族、邮政编码和一份评估碘源的经过验证的饮食问卷。
810 名参与者提供了 737 份尿样。664 名参与者提供了饮食习惯和碘状况的数据。中位数尿碘排泄量为 80.1μg/L（IQR 56.9-109.0）。51%（n=379）的参与者尿碘测量值表明存在轻度碘缺乏，16%（n=120）存在中度缺乏，1%（n=8）存在重度缺乏。碘缺乏症的患病率在贝尔法斯特最高（85%，n=135）。自来水碘浓度较低或无法检测，与尿碘浓度无正相关关系。多变量一般线性模型分析证实，尿碘排泄量低与夏季采样（p<0·0001）、英国地理位置（p<0·0001）、牛奶摄入量低（p=0·03）和鸡蛋摄入量高（p=0·02）之间存在独立关联。
我们的研究结果表明，英国存在碘缺乏。由于发育中的胎儿对碘缺乏的不良影响最敏感，即使母体和胎儿甲状腺功能的微小波动也会对神经发育产生影响，因此这些研究结果具有潜在的重要公共卫生意义。本研究引起了对全面调查英国碘状况和实施基于证据的碘补充建议的迫切需求。
临床内分泌学信托基金。
