The Prevalence and Risk Factors Associated with Iodine Deficiency in Canadian Adults

Iodine is a trace micronutrient that is critical for normal thyroid function and human health. Inadequate dietary intake is associated with cognitive impairment, infertility, growth retardation and iodine deficiency disorders in affected populations. Herein, we examined the prevalence of iodine deficiency in adults (median age of 61 years) based on the analysis of 24 h urine samples collected from 800 participants in four clinical sites across Canada in the Prospective Urban and Rural Epidemiological (PURE) study. Urinary iodide together with thiocyanate and nitrate were measured using a validated capillary electrophoresis assay. Protective/risk factors associated with iodine deficiency were identified using a binary logistic regression model, whereas daily urinary iodine concentration (24 h UIC, μg/L) and urinary iodine excretion (24 h UIE, μg/day) were compared using complementary statistical methods with covariate adjustments. Overall, our Canadian adult cohort had adequate iodine status as reflected by a median UIC of 111 μg/L with 11.9% of the population <50 μg/L categorized as having moderate to severe iodine deficiency. Iodine adequacy was also evident with a median 24 h UIE of 226 μg/day as a more robust metric of iodine status with an estimated average requirement (EAR) of 7.1% (< 95 μg/day) and a tolerable upper level (UL) of 1.8% (≥1100 μg/day) based on Canadian dietary reference intake values. Participants taking iodine supplements (OR = 0.18; p = 6.35 × 10⁻⁵), had greater 24 h urine volume (OR = 0.69; p = 4.07 × 10⁻⁴), excreted higher daily urinary sodium (OR = 0.71; p = 3.03 × 10⁻⁵), and/or were prescribed thyroxine (OR = 0.33; p = 1.20 × 10⁻²) had lower risk for iodine deficiency. Self-reported intake of dairy products was most strongly associated with iodine status (r = 0.24; p = 2.38 × 10⁻⁹) after excluding for iodine supplementation and T4 use. Participants residing in Quebec City (OR = 2.58; p = 1.74 × 10⁻⁴) and Vancouver (OR = 2.54; p = 3.57 × 10⁻⁴) were more susceptible to iodine deficiency than Hamilton or Ottawa. Also, greater exposure to abundant iodine uptake inhibitors from tobacco smoking and intake of specific goitrogenic foods corresponded to elevated urinary thiocyanate and nitrate, which were found for residents from Quebec City as compared to other clinical sites. Recent public health policies that advocate for salt restriction and lower dairy intake may inadvertently reduce iodine nutrition of Canadians, and further exacerbate regional variations in iodine deficiency risk.     

Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway

Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother’s breast milk and in infant’s urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother–infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.     

Iodine and Iodine Deficiency: A Comprehensive Review of a Re-Emerging Issue

Iodine is a mineral nutrient essential for the regulation of a variety of key physiological functions including metabolism and brain development and function in children and adults. As such, iodine intake and status within populations is an area of concern and research focus. This paper will review recently published studies that focus on the re-emerging issue of iodine deficiency as a global concern and declining intake among populations in developed countries. Historically, the implementation of salt-iodization programs worldwide has reduced the incidence of iodine deficiency, but 30% of the world’s population is still at risk. Iodine nutrition is a growing issue within industrialized countries including the U.S. as a result of declining iodine intake, in part due to changing dietary patterns and food manufacturing practices. Few countries mandate universal salt iodization policies, and differing agriculture and industry practices and regulations among countries have resulted in inconsistencies in supplementation practices. In the U.S., in spite of salt-iodization policies, mild-to-moderate iodine deficiency is common and appears to be increasing. European countries with the highest incidence of deficiency lack iodization programs. Monitoring the iodine status of at-risk populations and, when appropriate, public health initiatives, appear to be warranted.     

Application of a Modified Healthy Eating Index (HEI-Flex) to Compare the Diet Quality of Flexitarians,Vegans and Omnivores in Germany

Interest in plant-based nutrition has steadily increased in the western world in the recent years. The number of people following a meat-reduced, flexitarian diet is growing continuously. However, little is known about the diet quality of flexitarians compared to vegans or omnivores. Therefore, in this cross-sectional study, the food intake of 94 participants aged between 25–45 years was recorded via a validated food frequency questionnaire and 28 self-designed questions about the consumption of plant-based alternatives. An adapted Healthy Eating Index, HEI-flex, was developed to evaluate the diet quality of flexitarians, vegans and omnivores. Higher score points (SP) of the HEI-flex are associated with higher compliance with the official diet recommendations (V_max = 100 SP). Finally, flexitarians scored significantly more highly when compared to omnivores (54 ± 8 vs. 47 ± 9 SP; p = 0.008) but lower than vegans (54 ± 8 vs. 61 ± 10 SP; p = 0.010). The results showed that the HEI-flex is a useful tool for assessing and comparing the diet quality of flexitarians, vegans and omnivores. Despite the consumption of highly processed plant-based alternatives, reduction in meat and meat products seems to be accompanied by increased overall diet quality.     

Reflection of Dietary Iodine in the 24 h Urinary Iodine Concentration,Serum Iodine and Thyroglobulin as Biomarkers of Iodine Status: A Pilot Study

Background: The iodine status of the US population is considered adequate, but subpopulations remain at risk for iodine deficiency and a biomarker of individual iodine status has yet to be determined. The purpose of this study was to determine whether a 3 day titration diet, providing known quantities of iodized salt, is reflected in 24 h urinary iodine concentration (UIC), serum iodine, and thyroglobulin (Tg). Methods: A total of 10 participants (31.3 ± 4.0 years, 76.1 ± 6.3 kg) completed three, 3 day iodine titration diets (minimal iodine, US RDA, (United States Recommended Daily Allowance), and 3× RDA). The 24 h UIC, serum iodine, and Tg were measured following each diet. The 24 h UIC and an iodine-specific food frequency questionnaire (FFQ) were completed at baseline. Results: UIC increased an average of 19.3 μg/L for every gram of iodized salt consumed and was different from minimal to RDA (p = 0.001) and RDA to 3× RDA diets (p = 0.04). Serum iodine was different from RDA to 3× RDA (p = 0.006) whereas Tg was not responsive to diet. Baseline UIC was associated with iodine intake from milk (r = 0.688, p = 0.028) and fish/seafood (r = 0.646, p = 0.043). Conclusion: These results suggest that 24 h UIC and serum iodine may be reflective of individual iodine status and may serve as biomarkers of iodine status.     

2011年绵阳市碘缺乏病病情监测点及全市8～10岁儿童尿碘监测结果分析

目的 评价全民食盐加碘实施16年来绵阳市碘缺乏病防治效果,了解绵阳市城乡居民碘营养状况,为制定防控策略提供依据.方法 在四川省疾控中心按PPS法抽取的绵阳市1个县中进行碘缺乏病病情监测,按照方案要求在该县随机抽取1所小学,分别测定该校40名8～10岁儿童家中食用盐碘含量、人均食盐摄人量和甲状腺肿大率;随机抽取上述40名儿童中的12名测定尿碘、抽取学校附近3个乡的孕妇和哺乳妇女各5名,测定其尿碘;抽取学校附近集中式供水2份检测水碘含量.在全市其余8个县,按东、西、南、北、中5个方位各随机抽取1个乡的1所村小学,随机抽检20名8～10岁儿童的尿样进行尿碘监测.结果 病情监测点中,12名8 ～10岁儿童的尿碘中位数为379.5μg/L,孕妇尿碘中位数222.0 μg/L,哺乳妇女尿碘中位数为341.0 μg/L;碘盐含碘量27.00±3.45μg/L,碘盐覆盖率100％,合格碘盐食用率97.5％;8～10岁儿童甲状腺肿大率0％,人均食盐摄入量为6.81 ±0.66g/d;全市其余8个县8～ 10岁儿童尿碘中位数235.49 μg/L,尿碘值＜50.0 μg/L的儿童占2.5％,尿碘＞300.0 μg/L的占34.25％.结论 绵阳市人群碘营养状况良好,应警惕食盐过量的危害.     

2011年重庆市碘缺乏病监测结果分析

目的了解重庆市碘缺乏病现状和居民碘营养水平,为调整食盐加碘浓度提供科学依据。方法2011年按照“人口比例概率（PPS）抽样方法”,抽取30所小学作为监测点,每点随机抽取40名8～10岁儿童,检查甲状腺大小、尿碘水平和家中食盐碘含量;在每个监测点附近,抽取3个乡镇,每个乡镇随机捕取孕妇和哺乳期妇女各5人,检测尿碘含量。结果8—10岁儿童甲状腺检查1322人,甲肿率为5．52％;盐碘检测1321份,均数为30．46mg／kg,碘盐覆盖率、合格率、合格碘盐食用率、非碘盐率分别为99．70％、97．04％、96．74％和0．30％;尿碘检测1317人,中位数为254．1μg/L,100—199．99μg/L占23．23％,≥300p．g／L占36．52％;孕妇和哺乳期妇女尿碘共检测913人,中位数为222．5μg/L,100～199．99μg/L占30．34％,I〉300μg/L占32．20％。结论2011年重庆市儿童甲肿率较低,盐碘、尿碘指标达到国家消除标准;儿童尿碘超过适宜量,孕妇和哺乳期妇女尿碘处于适宜水平。     

Evaluation of a Validated Food Frequency Questionnaire for Self-Defined Vegans in the United States

This study aimed to develop and validate a de novo food frequency questionnaire for self-defined vegans in the United States. Diet histories from pilot samples of vegans and a modified ‘Block Method’ using seven selected nutrients of concern in vegan diet patterns, were employed to generate the questionnaire food list. Food frequency responses of 100 vegans from 19 different U.S. states were obtained via completed mailed questionnaires and compared to multiple telephone-conducted diet recall interviews. Computerized diet analyses were performed. Correlation coefficients, t-tests, rank, cross-tabulations, and probability tests were used to validate and compare intake estimates and dietary reference intake (DRI) assessment trends between the two methods. A 369-item vegan-specific questionnaire was developed with 252 listed food frequency items. Calorie-adjusted correlation coefficients ranged from r = 0.374 to 0.600 (p < 0.001) for all analyzed nutrients except calcium. Estimates, ranks, trends and higher-level participant percentile placements for Vitamin B₁₂ were similar with both methods. Questionnaire intakes were higher than recalls for most other nutrients. Both methods demonstrated similar trends in DRI adequacy assessment (e.g., significantly inadequate vitamin D intake among vegans). This vegan-specific questionnaire can be a useful assessment tool for health screening initiatives in U.S. vegan communities.     

2011年四川省碘缺乏病监测结果分析

目的掌握四川省碘缺乏病病情、居民碘营养水平及防治措施落实情况,为制订防治措施提供科学依据。方法按＂人口比例概率抽样方法＂（PPS）在全省抽取30个县,每个县抽取1所小学;每个小学抽查40名8～10岁儿童甲状腺容积,并定量检测其家中食用盐碘含量;抽取其中12名儿童检测尿碘,并调查其家中居民人均日盐摄入量;在抽中学校附近选择3个乡（镇、街道办）,每个乡（镇、街道办）抽取孕妇和哺乳妇女各5人检测尿碘;在抽中学校的所在村（居委会）,按东、西、南、北、中各抽取1份饮用水水样,如为集中式供水地区,则采集2份末梢水样检测水碘。全省在上述PPS法未抽到的152个县中,每县按东、西、南、北、中5个方位各抽取1个乡（镇、街道）,每个乡（镇、街道）抽取1所小学,每所小学抽检20名8～10岁儿童（男、女各半）尿碘。结果 B超法检查儿童1 221人,甲状腺肿大率4.1%;检测盐样1 206份,合格碘盐食用率98.1%,碘盐覆盖率99.9%,碘盐合格率98.2%,盐碘中位数32.8 mg/kg;检测儿童尿碘15393份,尿碘中位数208.9μg/L,其中男性儿童尿碘中位数（214.9μg/L）高于女性（203.2μg/L,Z=6.97,P〈0.05）;孕妇尿碘457份,尿碘中位数170.8μg/L;哺乳妇女尿碘452份,尿碘中位数159.5μg/L;水碘81份,水碘中位数2.7μg/L,范围0.2～49.6μg/L,水碘低于10μg/L比例为82.7%（67/81）;调查363户家庭食盐摄入量,人均日摄盐量8.46 g。结论四川自然环境普遍缺碘;人群碘营养水平总体适宜,继续保持消除碘缺乏病状态。     

2000-2010年四川省碘缺乏病实验室质量控制网络考核

目的通过回顾11年四川省碘缺乏病实验室质控网络运行情况,总结质控工作存在的不足,进一步加强实验室质控,保证碘缺乏病防治监测的质量。方法对2000-2010年全省各级碘缺乏病实验室参加外部质控考核结果进行统计分析。结果 11年来四川省级实验室盐碘和尿碘的考核结果均为合格,尿碘的Z分值|Z间|和|Z内|均≤2。市州级实验室盐碘考核合格率为87.5%～100%,尿碘考核合格率为93.3%～100%,尿碘的|Z间|≤2占97.2%,2<|Z间|<3占2.8%,|Z间|≥3占0%。,|Z内|≤2占94.4%,2<|Z内|<3占3.9%,|Z内|≥3占1.7%。区县级实验室盐碘考核合格率为86.1%～100%。结论四川省碘缺乏病实验室质控网络已全面覆盖到全省所有市州和区县实验室,各级实验室的盐碘和尿碘检测能力保持在较高的水平。     

Iodine status in Melbourne adults in the early 1990s and 2007-08

Objective: To investigate the iodine status of Melbourne adults in 1992–94 and 2007–08, and to assess dietary iodine intake to enable comparison with recommended Nutrient Reference Values. Method: A cross‐sectional study utilising 24‐hr urine samples collected at two time points in a random sample of the Melbourne Collaborative Cohort Study. Two hundred and fifty seven adults (128 males, 129 females) in 1992–94, with a mean age of 56 years, and 265 adults (132 males, 133 females) in 2007–08, with a mean age of 68 years, were assessed, all being Melbourne residents. Urinary iodine concentration (UIC) was determined and daily urinary iodine excretion and daily iodine intake were assessed. Results: In 1992–94, the median UIC was 27 μg/L and 84% had UIC <50 μg/L. The median daily iodine intake was 51 μg/d, and 83% of participants had dietary iodine intakes below the Estimated Average Requirement of 100 μg/d. In 2007–08, the median UIC was 49 μg/L, 51% had UIC <50 μg/L and the median daily iodine intake was 98 μg/d, with 52% of intakes below the EAR. Conclusion: Melbourne adults were moderately iodine deficient in 1992–94, and borderline moderately deficient in 2007–08. Implications: While iodine status appears to have improved, it remains below an adequate level for much of the adult population of Victoria. Adequate monitoring is fundamental to assess whether the mandatory use of iodised salt in bread is effective in reducing iodine deficiency across all population groups.     

Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review

Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy, eggs, poultry and fish which will be beneficial for both health and the environment. A systematic review of observational and intervention studies published between 2000 and January 2020 was conducted to assess nutrient intake and status in adult populations consuming plant-based diets (mainly vegetarian and vegan) with that of meat-eaters. Mean intake of nutrients were calculated and benchmarked to dietary reference values. For micronutrient status, mean concentrations of biomarkers were calculated and compared across diet groups. A total of 141 studies were included, mostly from Europe, South/East Asia, and North America. Protein intake was lower in people following plant-based diets compared to meat-eaters, but well within recommended intake levels. While fiber, polyunsaturated fatty acids (PUFA), folate, vitamin C, E and magnesium intake was higher, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake was lower in vegetarians and vegans as compared to meat-eaters. Intake and status of vitamin B12, vitamin D, iron, zinc, iodine, calcium and bone turnover markers were generally lower in plant-based dietary patterns compared to meat-eaters. Vegans had the lowest vitamin B12, calcium and iodine intake, and also lower iodine status and lower bone mineral density. Meat-eaters were at risk of inadequate intakes of fiber, PUFA, α-linolenic acid (ALA), folate, vitamin D, E, calcium and magnesium. There were nutrient inadequacies across all dietary patterns, including vegan, vegetarian and meat-based diets. As plant-based diets are generally better for health and the environment, public health strategies should facilitate the transition to a balanced diet with more diverse nutrient-dense plant foods through consumer education, food fortification and possibly supplementation.     

Moving Toward a Plant-based Diet: Are Iron and Zinc at Risk?

With reduced intake of meat and increased intake of phytate-containing legumes and whole grains, movement toward plant-based diets reduces dietary iron and zinc absorption. Although vegetarians have lower iron stores, adverse health effects of lower iron and zinc absorption have not been demonstrated with varied, plant-based diets consumed in developed countries. Improved assessment methods and monitoring are needed to detect and prevent possible iron and zinc deficiency with plant-based diets.     

Assessment of Iodine Concentration in Human Milk from Donors: Implications for Preterm Infants

Preterm infants are particularly vulnerable to developing iodine deficiency. Donor human milk (DHM) is the preferred feeding option if the mother’s own milk (MOM) is not available, but information on DHM iodine concentration (DHMIC) is lacking. Hence, we aimed to assess DHMIC to further evaluate the adequacy of iodine provision in preterm infants. Finally, associations that might influence DHMIC were studied. In 113 donors, we measured iodine intake by evaluating dietary records for five consecutive days with the DIAL^® Software. From the second day of dietary record, donors provided human milk samples (at least one per day) for four consecutive days. Daily human milk samples were analyzed for DHMIC. A DHMIC ≥ 200 µg/L was considered an adequate iodine content for preterm infants. DHMIC and urine iodine concentration (UIC) were determined using ICP-MS. In our study, 83.2% of donors had a full-term infant. Breastfeeding time range was 1.5–49.4 months. During the dietary record, 55.8% took iodine-containing supplements, providing 40–200 µg/day of iodine. The medians (p25, p75) UIC and DHMIC were 112.4 (75.8, 160.1) and 148.5 (97.6, 206.1) µg/L, respectively. In this iodine-sufficient population, 70% had a DHMIC of <200 µg/L. Donors’ intake of iodine-containing supplements was associated with higher DHMIC.     

Iodine Status and Thyroid Function in a Group of Seaweed Consumers in Norway

Seaweeds, or macroalgae, may be a good dietary iodine source but also a source of excessive iodine intake. The main aim in this study was to describe the iodine status and thyroid function in a group of macroalgae consumers. Two urine samples were collected from each participant (n = 44) to measure urinary iodine concentration (UIC) after habitual consumption of seaweed. Serum thyroid stimulating hormone (TSH), free thyroxine (fT₄), free triiodothyronine (fT₃), and peroxidase autoantibody (TPOAb), were measured in a subgroup (n = 19). A food frequency questionnaire and an iodine-specific 24 h recall were used to assess iodine intake and macroalgae consumption. The median (p25–p75) UIC was 1200 (370–2850) μg/L. Median (p25–p75) estimated dietary iodine intake, excluding macroalgae, was 110 (78–680) μg/day, indicating that seaweed was the major contributor to the iodine intake. TSH levels were within the reference values, but higher than in other comparable population groups. One third of the participants used seaweeds daily, and sugar kelp, winged kelp, dulse and laver were the most common species. Labelling of iodine content was lacking for a large share of the products consumed. This study found excessive iodine status in macroalgae consumers after intake of dietary seaweeds. Including macroalgae in the diet may give excessive iodine exposure, and consumers should be made aware of the risk associated with inclusion of macroalgae in their diet.     

补碘对缺碘地区人群垂体—甲状腺功能的影响

目的;观察补碘对缺碘人群垂体－甲状腺功能的影响。方法：应用免疫放射分析和放射免疫分析测定缺碘地区人群口服碘油前后的垂体－甲状腺激素变化。结果：补碘早期引起缺碘机体甲状腺激素水平异常变化,导致甲状腺功能紊乱;中期使缺碘造成的甲状腺功能高代偿状态基本趋于正常;后期机体因碘营养水平下降,使甲状腺功能又呈代学状态。结论：补碘虽可显著改善缺碘造成的甲状腺功能高代偿状态,但早期会造成部分机体垂体－甲状腺功能紊乱,发生一过性亚临床性甲状腺疾病。     

Iodine Status of 6–12-Year-Old Children in Russia over the Past 10 Years: A Scoping Review

Iodine is an essential element for growth and development of children. Ensuring adequate iodine intake and monitoring iodine intake are important public health concerns. According to the World Health Organization, a population-based assessment of iodine status is often done by measuring urine iodine concentration (UIC) in children aged 6–12 years. National data for large countries may hide regional differences in the UIC. Currently, there is limited data on the iodine status of children in Russia. We summarized the evidence on the iodine status of children in Russia using both international and local literature in accordance with the PRISMA guidelines. A total of 2164 studies were identified, 12 of which met the selection criteria and covered 10 of 85 federal subjects. For most of the Russian regions there was no information on UIC. A range of methodologies were used to determine UIC. The median UIC ranged from 46 μg/L in the mountainous areas in the Republic of Kabardino-Balkaria, which corresponds to a moderate iodine deficiency (ID), to 719 μg/L in the town of Turinsk (Sverdlovsk region) indicating excessive of iodine intake. Nationwide monitoring should be implemented in Russia and public health measures should be adjusted to regional and local conditions to ensure adequate iodine nutrition for all citizens.     

四川省实现消除碘缺乏病目标县级考评结果分析

目的评估四川省实现县级消除碘缺乏病目标的结果。方法按照《四川省实现消除碘缺乏病目标县级考核评估方案》进行。结果全省共182个县,组织管理等综合评分均在85分以上,平均为92.57分;180个县的合格碘盐食用率大于90%,全省合格碘盐食用率为97.4%;182个县尿碘中位数大于100μg/L,全省中位数为215.6μg/L,〈50μg/L占3.3%。结论四川省有98.9%的县（市、区）实现了消除碘缺乏病目标。     

适碘地区成人、儿童和孕妇碘营养状况调查

目的 了解自1996年全民食盐加碘政策实行以来,中国适碘地区成人、学龄儿童和孕妇的碘营养状况及特征。方法 采用横断面调查方法,选择河北省沧州市海兴县348名成人与150名学龄儿童及天津市174名孕晚期孕妇作为研究对象,测定成人、学龄儿童和孕妇空腹晨尿的尿碘水平及分布特征。结果 适碘地区成人、学龄儿童和孕妇尿碘中位数分别为185.20、123.13和217.06 μg/L,均为碘摄入适宜水平;适碘地区62.07%成人、68.67%儿童和63.22%孕妇碘营养状况处于富足水平,但仍有12.93%成人、22.00%儿童与27.59%孕妇为碘缺乏状态,不同人群尿碘水平分布差异有统计学意义（χ²=33.738,P<0.05）。结论 3种人群的碘营养状况适宜,但学龄儿童和孕妇出现了一定程度的碘缺乏,适碘地区特殊人群碘缺乏问题不容忽视。