Call for Maternal Iodine Supplementation in UK

Becky McCall

August 11, 2015

Universal iodine supplementation during pregnancy and breastfeeding increases a child's intelligent quotient (IQ) by 1.22 points and saves the UK National Health Service (NHS) £200 per pregnant woman and society nearly £4500 per person, indicates a large new population-based study.

This is the first cost-effectiveness evaluation of iodine supplementation in pregnancy in a mild to moderately iodine-deficient population — in this instance, the United Kingdom, say the authors.

"For the NHS, it would be cost-effective and beneficial for women to universally have pregnancy supplements that include iodine," remarked Kate Jolly, PhD, from the School of Health and Population Sciences, University of Birmingham, United Kingdom, a coauthor of the study published online in Lancet Diabetes and Endocrinology on August 9.

"In particular, I would like the government to provide iodine supplementation in the NHS's 'Healthy Start' vitamins for pregnant women," she added in an interview with Medscape Medical News.

The United Kingdom, unlike many other developed countries, does not recommend iodine supplementation in pregnancy, nor are any foods in the United Kingdom fortified with this element.

Iodine deficiency in pregnant women is linked to reduced cognitive ability in their children. Previous studies, including the United Kingdom's Avon Longitudinal Study of Parents and Children (ALSPAC), have found that children of mothers who were mildly iodine deficient in the first trimester of pregnancy had lower IQ at age 9 years.

Supporting the work, Elizabeth Pearce, MD, from Boston University School of Medicine, Massachusetts, who wrote an editorial accompanying the new paper, noted that "an urgent need exists to protect unborn children in the UK; the study...shows the costs of inaction in terms of both economics and lost human potential."

Stressing the importance of appropriate recommendations, she urged that "updating dietary reference values to be in line with international standards, recommendation of iodine supplements for pregnancy and lactation, and development of a national plan to monitor urinary iodine concentrations in pregnant women...be priorities."

United Kingdom an Outlier on Recommendations for Iodine Deficiency

Recent surveys have found that parts of the UK population are mildly to moderately iodine deficient, and currently, iodine supplements are not recommended there, nor is food or salt fortified with the element. As such, the major source of iodine in the UK diet is dairy produce resulting from iodized cattle feed.

This situation is at odds with other countries that recommend iodine supplementation during pregnancy, including Denmark, Switzerland, the United States, and China.

And "faced with similar circumstances, Australia and New Zealand both opted to mandate the use of iodized salt in breads and to recommend iodine supplementation for pregnant and lactating women," noted Dr Pearce.

In the United States, the Institute of Medicine recommends a daily iodine intake of 220 µg during pregnancy and 290 µg during lactation, while the American Thyroid Association recommends that women receive prenatal vitamins containing 150 µg of iodine daily during pregnancy and lactation.

The World Health Organization recommends 250 µg of iodine daily for pregnant and lactating women.

In light of the fact that the UK guidance on iodine supplementation is effectively "out of kilter with many other countries," Dr Jolly and her colleagues developed an economic model to compare the costs and benefits of a strategy of providing iodine-supplementation tablets vs no iodine supplementation for pregnant women in the United Kingdom.

Benefits to IQ; Healthcare and Societal Cost Savings

They assessed data from economic studies that linked IQ and income, as well as clinical data (eg, ALSPAC) relating to iodine deficiency in pregnant women and the effect on their children's IQ.

The analysis was conducted from the perspective of healthcare costs and societal costs of providing iodine supplementation during pregnancy or not.

"Benefits to the health service were reduced healthcare costs for children with a higher IQ, and societal costs were reduced educational costs for children with a lower IQ," explained Dr Jolly.

"The value of an IQ point was the added lifetime earnings of someone with a higher IQ," she added. This amounted to a lifetime earnings premium of £3297.

Also included in the analysis were the most severe harms possible with supplementation — for example, women with undiagnosed thyroid problems during pregnancy and the worst potential outcomes associated with this.

Both the healthcare and societal calculations revealed that iodine supplementation was less costly and more effective compared with no supplementation in pregnancy.

From the NHS perspective, where only health-related costs were taken into account, iodine supplementation saved £199 per pregnant woman and increased IQ by an average 1.22 IQ points for the unborn infants.

From the societal perspective, iodine supplementation was cost saving with a net value of £4476 per pregnant woman.

After computing all these different factors related to iodine deficiency, the researchers found that "iodine supplementation emerged as a consistently cost-effective approach for pregnant women — or ideally 3 months prior to pregnancy and until the end of breastfeeding," said Dr Jolly.

And while she and Dr Pearce say a large randomized controlled trial would provide more conclusive answers than an economic model, there are issues around whether a placebo group is ethically acceptable, they note.

This modeling evaluation was therefore a more viable option, and Dr Pearce concludes that even though the assumptions used were "conservative," it presents "a compelling economic argument in favor of iodine supplementation for pregnant and lactating women in the UK."

Dr Jolly is a member of the UK Iodine Group and has declared no other relevant financial relationships. The coauthors declare no relevant financial relationships, as does Dr Pearce.

Lancet Diabetes Endocrinol. Published online in August 10, 2015. Abstract, Editorial

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