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Editorial

Free Access

Iodine Status in Europe in 2014

Lazarus J.H.

Author affiliations

Thyroid Research Group, Institute of Molecular and Experimental Medicine, Cardiff University, University Hospital of Wales, Cardiff, UK

Corresponding Author

Prof. John H. Lazarus, Regional Coordinator, West and Central Europe, ICCIDD GN

Thyroid Research Group, Institute of Molecular and Experimental Medicine

Cardiff University, University Hospital of Wales

Heath Park, Cardiff CF14 4XN (UK)

E-Mail lazarus@cf.ac.uk

Related Articles for ""

Eur Thyroid J 2014;3:3-6

Iodine deficiency has been recognised as a worldwide problem since the last century [1]. The International Council for Iodine Deficiency Disorders Global Network (ICCIDD GN) has underpinned remarkable progress in ameliorating this problem during the last nearly 30 years and especially during the last decade [2]. The number of iodine-deficient countries in the world has decreased from 54 in 2003 to 47 in 2007 and 32 in 2011 [3]. This remarkable rate of progress has been largely due to intensive work by the ICCIDD GN, UNICEF and WHO. Nevertheless, of these 32 countries, 11 (34%) are in Europe, the largest number from any continent [3].

West and Central Europe has a total population of about 600 million situated in 35 countries (table 1), with country populations ranging from 0.3 to 75 million. Attention was drawn to the iodine deficiency problem in this area more than 10 years ago [4]. In general, the iodine deficiency is mild, but nevertheless this may have an impact on childhood development. For example, mild-to-moderate iodine deficiency in the first trimester of pregnancy was associated with increased odds of the intelligence quotient of offspring being in the lowest quartile (odds ratio: 1.43; 95% CI: 1.04-1.98; p = 0.03), with the greatest negative impact observed with the verbal intelligence quotient (odds ratio: 1.66; 95% CI: 1.20-2.31; p = 0.002) [5]. A review of the current evidence indicates that a correction of mild-to-moderate iodine deficiency improves cognitive performance in school-age children, but there are insufficient data on developmental outcomes in early life [6]. There are 2 randomised studies of iodine supplementation in children with mild iodine deficiency in Albania [7] and New Zealand [8] showing improved cognition. However, large-scale controlled trials are now needed to clarify whether gestational iodine supplementation will benefit infant and childhood neurodevelopment in more European countries with marginal iodine deficiency.

Table 1

Countries of the ICCIDD GN in West and Central Europe

http://www.karger.com/WebMaterial/ShowPic/152638

During 2013, a postal enquiry survey was performed requesting relevant information on the iodine status from all national coordinators of the ICCIDD GN in the West and Central European region. In addition to the 35 countries, there are 3 (Austria, Kosovo and Montenegro) where there is no national coordinator for the ICCIDD GN and from where no data are available for 2013. Information from all countries was not available on some items of the questionnaire, but all countries with an ICCIDD national coordinator responded. It should be noted that the WHO/ICCIDD criteria for an adequate iodine status in a population are a median urinary iodine (UI) of 100 µg/l or more, with <20% having a UI of <50 µg/l [3]. In pregnancy, the median UI should be at least 150 µg/l, on account of increased iodine requirements during gestation and lactation [9].

The results of the questionnaire showed, firstly, that salt iodisation is mandatory in 13 countries and not mandatory in 21 (no response to this question was received from 1 country). This represents at least 400 million people living in countries with no mandatory legislation for iodised salt. No data are available from this survey on household iodised salt coverage rates. Some countries, such as Switzerland, have a high rate (80%), but in others (e.g. the UK) the coverage is only about 5%. A recent survey of the iodine status was performed within the last 2 years in 16 countries and not performed in 14, with information lacking from 5 countries. The median UI concentration, either nationally or regionally, ranged from 78 to 252 µg/l in 26 countries, with 6 of those countries (23%) having a UI of <100 µg/l. Data on the iodine status in pregnancy were available from 21 countries and indicated that it was adequate in only 8 countries (38%). When asked as to whether there is ongoing monitoring of the iodine status in the country, 16 national coordinators responded positively and 17 indicated that there was no monitoring.

A few examples will illustrate the situation further. In the Netherlands, iodine intake by pregnant women is sufficient as determined by a single UI measurement in more than 1,000 pregnant women in Rotterdam with a median UI of 225 µg/l [10]. This is in contrast to Norway, where the median UI was <100 µg/l in an admittedly smaller sample [11]. In Poland there has been an improvement in median UI in pregnancy from 105 µg/l in 2010 to 121 µg/l in 2011, but this figure is still suboptimal [12]. A comprehensive evaluation of the iodine status in pregnancy in Belgium has shown that median UI values are suboptimal [13]. This is despite the fact that 60% of the women reported taking iodine supplements during gestation [14]. Interestingly, the frequency of elevated neonatal thyroid-stimulating hormone levels was still low (3%) in this population [15]. In Denmark, while the majority of pregnant women took iodine-containing supplements, the subgroup of non-users was still iodine deficient after the introduction of iodine fortification of salt [16].

The iodine status is adequate in some countries. Following a new salt law in Croatia (population: 4.5 million) in 1996, UI values have steadily increased from <100 µg/l in 1997 to 150 µg/l in 2002, and even higher (approx. 200 µg/l) in 2009 [17]. This is a success story in a small country but it also shows the necessity of further monitoring, in this case to avoid an iodine excess. In Kosovo and Montenegro, in 2007 there was optimum iodine nutrition [18], and this is continuing in Kosovo, but not in Montenegro because of a lack of funding [van der Haar, pers. commun., 2013]. In Romania (population: 19 million), subsequent to mandatory iodisation in 2002/2003, the UI has increased from approximately 90 µg/l in 2004 to 135 µg/l in 2011, which is a satisfactory outcome. However, there is a suboptimal iodine status of pregnant women in nine countries (Albania, Belgium, Czech Republic, Greece, Israel, Norway, Portugal, Romania and Serbia) and evidence of iodine deficiency in the general as well as the pregnant population in 5 countries (France, Hungary, Ireland, Italy and the UK). This means that an inadequate iodine supply in pregnancy is present in approximately 30% of the European countries.

The most populous countries in the region are France, Germany, Italy, Spain, Turkey and the UK, with a combined population of about 390 million, i.e. two thirds of the whole area. Only 2 of these countries (Italy and Spain) have iodisation legislation, which is not always adhered to. In contrast, all but 2 of the countries (Spain and the UK) have national monitoring. There have been several regional studies in Spain, e.g. in Catalonia [19]. The UI concentration in the general population is adequate in Spain (although deficient in Northern Spain [20]) and France, and borderline or mildly deficient in the other countries. Moderate-to-severe iodine deficiency still existed in 27.8% of the Turkish population in 2007, which was much better than in 1997 and 2002 [21].

In the UK, iodine deficiency has emerged as a public health issue following several decades of apparent iodine sufficiency [22]. There is evidence from a national survey of iodine deficiency in 15-year-old schoolgirls [23] as well as in pregnant women from several areas [24,25]. A longitudinal study on children from their mothers' pregnancy to the age of 20 years has shown significant associations between suboptimal maternal iodine nutrition and intellectual performance [26]. Despite the fact that probably around two thirds of the pregnant women in the UK are iodine deficient, a recent government scoping paper from the standing advisory commission on nutrition has not recommended iodine supplementation in pregnancy and even still questions the methodology of the iodine status assessment in populations [27]. There is a requirement for a national large-scale survey of iodine supply in pregnant women in the UK to confirm the initial findings from relatively small samples. There are some indications that UI concentrations in young UK schoolchildren are adequate [Rayman, pers. commun.]. However, this group usually consumes the largest amount of milk and its iodine status cannot be used as a proxy for the adult population [28].

In summary, there is a re-emerging iodine deficiency in industrialised countries of Europe, although the iodine status of some countries is satisfactory. Of particular concern is the fact that pregnant women in many countries have inadequate iodine nutrition. It also appears that about 400 million people from 20 countries have no or limited access to iodised salt. The demonstration of adequate iodine intake in some sections of the population (e.g. schoolchildren) should not be a barrier to recommending a national salt iodisation programme.

The overall picture of iodine nutrition in Europe in the early 21st century is still a cause for concern (with some exceptions). Salt iodisation is known to be a highly cost-effective method of supplying iodine to a population, although there are other sources of iodine that can be employed. The ICCIDD GN has had an admirable record in advocacy during the past nearly 30 years in relation to the promotion of universal salt iodisation and to an increasing awareness of iodine deficiency and its adverse consequences particularly in children. A significant part of the population in Europe is mildly deficient in iodine; an increase in dietary iodine consumption by 50-100 μg/day would be beneficial, with minimal or no adverse consequences. More national data are required, particularly on the pregnant population, where current evidence - although incomplete for many countries - suggests that there is suboptimal iodine nutrition. We now need to move forward in Europe by increasing advocacy activities, providing more epidemiological evidence as well as involving the European Union in order to recognise and prevent the problems of iodine deficiency in its backyard.

Acknowledgements

The author thanks Dr. Frits van der Haar for his advice, and the national coordinators of the ICCIDD GN West and Central Europe for their cooperation.

Disclosure Statement

The author has nothing to disclose.


References

  1. Hetzel BS: The development of a global program for the elimination of brain damage due to iodine deficiency. Asia Pac J Clin Nutr 2012;21:164-170.
    External Resources
  2. Andersson M, Karumbunathan V, Zimmermann MB: Global iodine status in 2011 and trends over the past decade. J Nutr 2012;142:744-750.
  3. Zimmermann MB, Andersson M: Update of iodine status worldwide. Curr Opin Endocrinol Diabetes Obes 2012;19:382-387.
  4. Delange F: Iodine deficiency in Europe and its consequences: an update. Eur J Nucl Med Mol Imaging 2002;29:S404-S416.
  5. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP: Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 2013;382:331-337.
  6. Taylor PN, Okosieme OE, Dayan CM, Lazarus JH: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis. Eur J Endocrinol 2013;170:R1-R15.
  7. Zimmermann MB, Connolly K, Bozo M, Bridson J, Rohner F, Grimci L: Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. Am J Clin Nutr 2006;83:108-114.
    External Resources
  8. Gordon RC, Rose MC, Skeaff SA, Gray AR, Morgan KM, Ruffman T: Iodine supplementation improves cognition in mildly iodine-deficient children. Am J Clin Nutr 2009;90:1264-1271.
  9. WHO Secretariat, Andersson M, de Benoist B, Delange F, Zupan J: Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr 2007;10:1606-1611.
  10. Medici M, Ghassabian A, Visser W, de Muinck Keizer-Schrama SM, Jaddoe VW, Visser WE, Hooijkaas H, Hofman A, Steegers EA, Bongers-Schokking JJ, Ross HA, Tiemeier H, Visser TJ, de Rijke YB, Peeters RP: Women with high early pregnancy urinary iodine levels have an increased risk of hyperthyroid newborns: the population-based Generation R Study. Clin Endocrinol (Oxf) 2013, Doi: 10.1111/cen.12321, Epub ahead of print.
  11. Brantsæter AL, Abel MH, Haugen M, Meltzer HM: Risk of suboptimal iodine intake in pregnant Norwegian women. Nutrients 2013;5:424-440.
  12. Szybiński Z: Work of the Polish Council for Control of Iodine Deficiency Disorders, and the model of iodine prophylaxis in Poland. Endokrynol Pol 2012;63:156-160.
    External Resources
  13. Moreno-Reyes R, Glinoer D, Van Oyen H, Vandevijvere S: High prevalence of thyroid disorders in pregnant women in a mildly iodine-deficient country: a population-based study. J Clin Endocrinol Metab 2013;98:3694-3701.
  14. Vandevijvere S, Amsalkhir S, Mourri AB, Van Oyen H, Moreno-Reyes R: Iodine deficiency among Belgian pregnant women not fully corrected by iodine-containing multivitamins: a national cross-sectional survey. Br J Nutr 2013;109:2276-2284.
  15. Vandevijvere S, Coucke W, Vanderpas J, Trumpff C, Fauvart M, Meulemans A, Marie S, Vincent MF, Schoos R, Boemer F, Vanwynsberghe T, Philips E, Eyskens F, Wuyts B, Selimaj V, Van Overmeire B, Kirkpatrick C, Van Oyen H, Moreno-Reyes R: Neonatal thyroid-stimulating hormone concentrations in Belgium: a useful indicator for detecting mild iodine deficiency? PLoS One 2012;7:e47770.
  16. Andersen SL, Sørensen LK, Krejbjerg A, Møller M, Laurberg P: Iodine deficiency in Danish pregnant women. Dan Med J 2013;60:A4657.
    External Resources
  17. Kusić Z, Jukić T, Rogan SA, Juresa V, Dabelić N, Stanicić J, Borić M, Lukinac L, Mihaljević I, Punda A, Smokvina A, Topalović Z, Katalenić M: Current status of iodine intake in Croatia: the results of 2009 survey. Coll Antropol 2012;36:123-128.
    External Resources
  18. van der Haar F, Gerasimov G, Tyler VQ, Timmer A: Universal salt iodization in the Central and Eastern Europe, Commonwealth of Independent States (CEE/CIS) Region during the decade 2000-2009: experiences, achievements, and lessons learned. Food Nutr Bull 2011;32(suppl):S175-S294.
    External Resources
  19. Vila L, Serra-Prat M, de Castro A, Palomera E, Casamitjana R, Legaz G, Barrionuevo C, Muñoz JA, García AJ, Lal-Trehan S, García A, Durán J, Puig-Domingo M: Iodine nutritional status in pregnant women of two historically different iodine-deficient areas of Catalonia, Spain. Nutrition 2011;27:1029-1033.
  20. Aguayo A, Grau G, Vela A, Aniel-Quiroga A, Espada M, Martul P, Castaño L, Rica I: Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain. J Trace Elem Med Biol 2013;27:302-306.
  21. Erdoğan MF, Ağbaht K, Altunsu T, Ozbaş S, Yücesan F, Tezel B, Sargin C, Ilbeğ I, Artik N, Köse R, Erdoğan G: Current iodine status in Turkey. J Endocrinol Invest 2009;32:617-622.
  22. Phillips DI: Iodine, milk, and the elimination of endemic goitre in Britain: the story of an accidental public health triumph. J Epidemiol Community Health 1997;51:391-393.
  23. Vanderpump MP, Lazarus JH, Smyth PP, Laurberg P, Holder RL, Boelaert K, Franklyn JA; British Thyroid Association UK Iodine Survey Group: Iodine status of UK schoolgirls: a cross-sectional survey. Lancet 2011;377:2007-2012.
  24. Bath S, Walter A, Taylor A, Rayman MP: Iodine status of UK women of childbearing age. J Hum Nutr Diet 2008;21:379-380.
    External Resources
  25. Pearce EN, Lazarus JH, Smyth PP, He X, Dall'amico D, Parkes AB, Burns R, Smith DF, Maina A, Bestwick JP, Jooman M, Leung AM, Braverman LE: Perchlorate and thiocyanate exposure and thyroid function in first-trimester pregnant women. J Clin Endocrinol Metab 2010;95:3207-3215.
  26. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP: Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 2013;382:331-337.
  27. The Scientific Advisory Committee on Nutrition (SACN). www.sacn.gov.uk (accessed December 15, 2013).
  28. Pearce EN, Andersson M, Zimmermann MB: Global iodine nutrition: where do we stand in 2013? Thyroid 2013;23:523-528.

Author Contacts

Prof. John H. Lazarus, Regional Coordinator, West and Central Europe, ICCIDD GN

Thyroid Research Group, Institute of Molecular and Experimental Medicine

Cardiff University, University Hospital of Wales

Heath Park, Cardiff CF14 4XN (UK)

E-Mail lazarus@cf.ac.uk


Article / Publication Details

Received: December 20, 2013
Accepted: January 17, 2014
Published online: March 01, 2014
Issue release date: March 2014

Number of Print Pages: 4
Number of Figures: 0
Number of Tables: 1

ISSN: 2235-0640 (Print)
eISSN: 2235-0802 (Online)

For additional information: https://www.karger.com/ETJ


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References

  1. Hetzel BS: The development of a global program for the elimination of brain damage due to iodine deficiency. Asia Pac J Clin Nutr 2012;21:164-170.
    External Resources
  2. Andersson M, Karumbunathan V, Zimmermann MB: Global iodine status in 2011 and trends over the past decade. J Nutr 2012;142:744-750.
  3. Zimmermann MB, Andersson M: Update of iodine status worldwide. Curr Opin Endocrinol Diabetes Obes 2012;19:382-387.
  4. Delange F: Iodine deficiency in Europe and its consequences: an update. Eur J Nucl Med Mol Imaging 2002;29:S404-S416.
  5. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP: Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 2013;382:331-337.
  6. Taylor PN, Okosieme OE, Dayan CM, Lazarus JH: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis. Eur J Endocrinol 2013;170:R1-R15.
  7. Zimmermann MB, Connolly K, Bozo M, Bridson J, Rohner F, Grimci L: Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. Am J Clin Nutr 2006;83:108-114.
    External Resources
  8. Gordon RC, Rose MC, Skeaff SA, Gray AR, Morgan KM, Ruffman T: Iodine supplementation improves cognition in mildly iodine-deficient children. Am J Clin Nutr 2009;90:1264-1271.
  9. WHO Secretariat, Andersson M, de Benoist B, Delange F, Zupan J: Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr 2007;10:1606-1611.
  10. Medici M, Ghassabian A, Visser W, de Muinck Keizer-Schrama SM, Jaddoe VW, Visser WE, Hooijkaas H, Hofman A, Steegers EA, Bongers-Schokking JJ, Ross HA, Tiemeier H, Visser TJ, de Rijke YB, Peeters RP: Women with high early pregnancy urinary iodine levels have an increased risk of hyperthyroid newborns: the population-based Generation R Study. Clin Endocrinol (Oxf) 2013, Doi: 10.1111/cen.12321, Epub ahead of print.
  11. Brantsæter AL, Abel MH, Haugen M, Meltzer HM: Risk of suboptimal iodine intake in pregnant Norwegian women. Nutrients 2013;5:424-440.
  12. Szybiński Z: Work of the Polish Council for Control of Iodine Deficiency Disorders, and the model of iodine prophylaxis in Poland. Endokrynol Pol 2012;63:156-160.
    External Resources
  13. Moreno-Reyes R, Glinoer D, Van Oyen H, Vandevijvere S: High prevalence of thyroid disorders in pregnant women in a mildly iodine-deficient country: a population-based study. J Clin Endocrinol Metab 2013;98:3694-3701.
  14. Vandevijvere S, Amsalkhir S, Mourri AB, Van Oyen H, Moreno-Reyes R: Iodine deficiency among Belgian pregnant women not fully corrected by iodine-containing multivitamins: a national cross-sectional survey. Br J Nutr 2013;109:2276-2284.
  15. Vandevijvere S, Coucke W, Vanderpas J, Trumpff C, Fauvart M, Meulemans A, Marie S, Vincent MF, Schoos R, Boemer F, Vanwynsberghe T, Philips E, Eyskens F, Wuyts B, Selimaj V, Van Overmeire B, Kirkpatrick C, Van Oyen H, Moreno-Reyes R: Neonatal thyroid-stimulating hormone concentrations in Belgium: a useful indicator for detecting mild iodine deficiency? PLoS One 2012;7:e47770.
  16. Andersen SL, Sørensen LK, Krejbjerg A, Møller M, Laurberg P: Iodine deficiency in Danish pregnant women. Dan Med J 2013;60:A4657.
    External Resources
  17. Kusić Z, Jukić T, Rogan SA, Juresa V, Dabelić N, Stanicić J, Borić M, Lukinac L, Mihaljević I, Punda A, Smokvina A, Topalović Z, Katalenić M: Current status of iodine intake in Croatia: the results of 2009 survey. Coll Antropol 2012;36:123-128.
    External Resources
  18. van der Haar F, Gerasimov G, Tyler VQ, Timmer A: Universal salt iodization in the Central and Eastern Europe, Commonwealth of Independent States (CEE/CIS) Region during the decade 2000-2009: experiences, achievements, and lessons learned. Food Nutr Bull 2011;32(suppl):S175-S294.
    External Resources
  19. Vila L, Serra-Prat M, de Castro A, Palomera E, Casamitjana R, Legaz G, Barrionuevo C, Muñoz JA, García AJ, Lal-Trehan S, García A, Durán J, Puig-Domingo M: Iodine nutritional status in pregnant women of two historically different iodine-deficient areas of Catalonia, Spain. Nutrition 2011;27:1029-1033.
  20. Aguayo A, Grau G, Vela A, Aniel-Quiroga A, Espada M, Martul P, Castaño L, Rica I: Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain. J Trace Elem Med Biol 2013;27:302-306.
  21. Erdoğan MF, Ağbaht K, Altunsu T, Ozbaş S, Yücesan F, Tezel B, Sargin C, Ilbeğ I, Artik N, Köse R, Erdoğan G: Current iodine status in Turkey. J Endocrinol Invest 2009;32:617-622.
  22. Phillips DI: Iodine, milk, and the elimination of endemic goitre in Britain: the story of an accidental public health triumph. J Epidemiol Community Health 1997;51:391-393.
  23. Vanderpump MP, Lazarus JH, Smyth PP, Laurberg P, Holder RL, Boelaert K, Franklyn JA; British Thyroid Association UK Iodine Survey Group: Iodine status of UK schoolgirls: a cross-sectional survey. Lancet 2011;377:2007-2012.
  24. Bath S, Walter A, Taylor A, Rayman MP: Iodine status of UK women of childbearing age. J Hum Nutr Diet 2008;21:379-380.
    External Resources
  25. Pearce EN, Lazarus JH, Smyth PP, He X, Dall'amico D, Parkes AB, Burns R, Smith DF, Maina A, Bestwick JP, Jooman M, Leung AM, Braverman LE: Perchlorate and thiocyanate exposure and thyroid function in first-trimester pregnant women. J Clin Endocrinol Metab 2010;95:3207-3215.
  26. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP: Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 2013;382:331-337.
  27. The Scientific Advisory Committee on Nutrition (SACN). www.sacn.gov.uk (accessed December 15, 2013).
  28. Pearce EN, Andersson M, Zimmermann MB: Global iodine nutrition: where do we stand in 2013? Thyroid 2013;23:523-528.
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