Strategies to Improve Iodine Status in Early Pregnancy
Phase: NA
Conditions: Iodine Deficiency, Pregnancy Related
Sponsor: Queen's University, Belfast

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Strategies to Improve Iodine Status in Early Pregnancy 
IRAS Number: 285499 
Sponsor number: EAT/5578/19 
Study Title 
Strategies to improve iodine status in early pregnancy 
Internal ref. no. (or short title) 
Strategies to improve iodine status in early pregnancy 
Study Design 
Quantitative randomized control trial (RCT) with dietary intervention 
Qualitative semi-structured interview 
Study Participants 
Women currently 6-16 weeks pregnant 
Women currently pregnant or with a child under 3 years old. 
Planned Size of Sample (if applicable) 
160 for RCT 
20 for semi-structured interview 
Follow up duration (if applicable) 
Until approximately 6 weeks post-natal – total of approximately 40 weeks 
involvement. 
Planned Study Period 
36 months 
Research Question/Aim(s) 
 
Does increasing daily cows’ milk consumption significantly improve iodine 
nutrition status in the first trimester of pregnancy to reach sufficiency? 
 
FUNDER(S) (Names and contact details of ALL 
organizations providing funding and/or support in 
kind for this study) 
FINANCIAL AND NON FINANCIALSUPPORT GIVEN 
Public Health Agency, R&D Division 
Doctoral Fellowship 
Queen’s University Belfast 
Supervision 
Belfast Trust and Social Care Trust 
Supervision 
 
Role of Study Sponsor and Funder 
This research project is being undertaken at Queen’s University Belfast as part of a PhD. 
Funding is from the Public Health Agency (PHA), Research and Development (R&D) Office in the form of a 
doctoral fellowship.  Regular updates on progress are required, however the PHA do not directly influence study 
design or results dissemination.  

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Contents 
1.0 Background  
 
 
 
 
 
 
 
 
1 
2.0 Research Aims 
 
 
 
 
 
 
 
 
1 
3.0 Plan of Investigation 
 
 
 
 
 
 
 
 
2 
3.1 Milk Intervention RCT  
 
 
 
 
 
 
2 
3.1.1 Study flow chart 
 
 
 
 
 
 
 
3 
3.1.2 Recruitment 
 
 
 
 
 
 
 
4 
3.1.3 Study design 
 
 
 
 
 
 
 
4-7 
3.1.4 Eligibility criteria 
 
 
 
 
 
 
 
7 
3.1.5 Data collection 
 
 
 
 
 
 
 
7 
3.1.6 Outcome measures  
 
 
 
 
 
 
8 
3.1.7 Statistical analysis 
 
 
 
 
 
 
 
8 
3.2 Semi-structured interviews 
 
 
 
 
 
 
9 
3.2.1 Study flow chart 
 
 
 
 
 
 
 
9 
3.2.2 Recruitment 
 
 
 
 
 
 
 
9 
3.2.3 Eligibility criteria  
 
 
 
 
 
 
 
10 
3.2.4 Study design 
 
 
 
 
 
 
 
10 
3.2.3 Data collection 
 
 
 
 
 
 
 
10 
 
3.2.4 Outcome measures  
 
 
 
 
 
 
10 
4.0 Data Management 
 
 
 
 
 
 
 
 
10 
5.0 Ethical Considerations  
 
 
 
 
 
 
 
11 
6.0 References 
 
 
 
 
 
 
 
 
 
11-12 
 
 
 
 
 
 
 
 

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1.0           Background 
Iodine is an essential component of thyroid hormones.  Iodine requirements increase during pregnancy and 
iodine deficiency in-utero and early life is accepted as the leading cause of preventable mental impairment 
worldwide. Two billion people are thought be iodine deficient worldwide.  While the effects of severe iodine 
deficiency are well described (cretinism and goitre), the effects of mild iodine deficiency are not well understood, 
particularly in pregnancy. However, a recent observational study in the United Kingdom (UK) has reported a 
dose-dependent relationship between the degree of mild iodine deficiency of the mother in first trimester and 
subsequent offspring cognition scores(Bath, 2019). 
In the UK, mild-moderate iodine deficiency was endemic in the past but from the 1930s onwards, “an accidental 
public health triumph” (Phillips, 1997) occurred with the use of iodine-containing cattle feed and cleaning agents 
in milking parlours. The richest source of iodine in the UK is cows’ milk and other dairy products. Salt fortification 
programmes exist in many parts of the world, endorsed as the optimal protection by the World Health 
Organisation (WHO). Historically food fortification has been a politically challenging issue in the UK and iodised 
salt availability is very low.  A study of iodine fortified salt availability across stores on the island of Ireland 
showed that of 89 stores, only 11 sold iodine-fortified salt, and 10 of these were in ethnic stores with a low 
market share(O’Kane et al., 2018; Shaw et al., 2019; Vanderpump et al., 2011; WHO, 2013).  
Our group in Northern Ireland (NI) surveyed one of the largest cohorts of teenage girls in the UK and 
demonstrated borderline sufficiency with geographical variations.  There was also a positive correlation between 
iodine status and milk consumption.  Our group has recently reported low levels of iodine awareness among 
pregnant women, with only 5% of pregnant women having any knowledge of iodine-containing foods and their 
importance.  Iodine deficiency in a large cohort of pregnant women in NI has been documented, which persisted 
across the trimesters, despite 50% of women taking a supplement containing iodine(Bath et al., 2016; McMullan, 
Hamill, et al., 2019; McMullan, Hunter, et al., 2019).   
Neonatal thyroid stimulating hormone (nTSH) levels from babies in Northern Ireland over 15 years were 
analysed and our group reported a rise in nTSH, indicative of a possible re-emergence of iodine deficiency. 
Seasonality was also demonstrated, which suggests that seasonal feeding patterns among milking cows may be 
relevant to the iodine in the food chain.  Our group has also published on selenium levels in pregnancy, air 
circulation of iodine on the island of Ireland and mapping of iodine status throughout Europe(Ittermann et al., 
2020; Mullan et al., 2018; Smyth et al., 2011). 
 
The Scientific Advisory Committee for Nutrition UK has called for further research on improving iodine nutrition. 
To our knowledge, this milk-based intervention study is the first of its kind and may offer an urgently required 
evidence base for options outside of fortification in the UK(Nutrition, 2014).  
2.0  
Research Aims 
We will conduct an RCT testing the hypothesis: increased intake of cows’ milk early in pregnancy will improve 
iodine nutrition.  We aim: 
1. To determine if 12-week free milk provision, along with education around iodine nutrition, compared with 
education alone increases the proportion of women who achieve adequate iodine status in pregnancy and the 
puerperium.  
2. To determine if 12-week free milk provision, along with education around iodine nutrition, compared with 
education alone, leads to a change in dietary behaviour throughout the rest of pregnancy and puerperium, once 
the intervention period has completed. 
3. To understand the possible barriers to increased iodine intake in pregnancy 
 
 
 
 
 
 
 
 

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3.0           Plan of Investigation 
 
3.1           Milk Intervention RCT 
 
 
Figure One: Flow chart showing the original plan for the RCT.  
 
 
Figure Two:  Flow chart showing the changes made due to the ongoing COVID-19 pandemic.   
 
The ongoing COVID-19 pandemic has meant that we have had to review our original research plan taking 
mitigating actions to ensure participant safety.  This has meant removing all visits to clinical areas, other than 
those required for usual clinical care.  In summary, these changes are as follows:   
 
Last menstrual period will be used to estimate gestational age.  This will avoid attending a clinical area for an 
ultrasound scan. 
 
In addition to remote recruitment, women will be recruited at their booking appointment.  There are no 
additional visits to clinical areas and contact with the research team at the booking appointment would be 
socially distanced and with appropriate personal protective equipment worn. 
 
Participants will complete consent forms and questionnaires (demographics, iodine knowledge and iodine 
specific food frequency questionnaire) online using Qualtrics software. Women recruited during their booking 
appointment will complete the consent form in the clinic prior to the collection of blood samples and the first 
urine sample. 
 
Four-day food diaries will be given (in person or by post) to participants, once consent form has been completed, 
along pre-paid envelope for returning food diaries. 
 
Thyroid function tests will be carried out at the participant’s booking appointment when routine bloods in 
prenatal care are being taken.  Participants will be asked to bring a specimen form to their appointment for the 
attention of the phlebotomist.  This will ensure blood samples taken for the purposes of this research are 
processed under the appropriate research code.   
TFTs at 
booking clinic 

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 
All urine samples, except the first, collected at the booking appointment, will be collected by post, or by 
contactless, doorstep, collection to avoid visits to clinical areas for research purposes. 
 
If randomised to receive free milk supply, contactless delivery will be provided.   
 
 
3.1.1  Study flow chart 
 
 
 
Recruitment
• Women currently 6-16 weeks pregnant
•Invitation letter and participant information sheet sent with booking appointment
•Posters in Royal Jubilee Maternity Hospital and fertility clinic
•Contact with research team at booking clinic.
Randomisation
• Stratified depending on  iodine supplementation
• Randomised using pre-determined randomisation schedule
• Half of the participants randomised to receive milk supply for 12 week intervnetion period
Study
• Thyroid function tests performed at booking clinic.
• Urinary iodine concentration from spot urine sample collected at enrolement, after 12 week intervention period, at 29 
weeks gestation and 6 weeks postnatally.
• Demographic questionnaire completed at beginning only.
• Food frequency questionnaire completed at beginning, after 12 weeks intervention, at 29 weeks gestation and post-natal.
• Four day food diary and knowledge questionnaire completed at beginning and post-natally. 
• Urine from infant collected at approximately 6 weeks post-natally.
• All receive BDA iodine factsheet.
Analysis
• Performed on pseudonymous data using SPSS
• Descriptive statistics of demographics to allow comparison with general population.
• Comparison of urinary iodine concentration amongst groups at various time points in the study.
• Comparison of infant's urinary iodine concentration with mother's iodine status.
Dissemination
• Results published in peer review journals
• Results shared with professional bodies and relevant policy makers
Informed consent

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3.1.2 
Recruitment 
 
Recruitment will be via several routes.  Women will receive an invitation letter and participant information sheet 
along with their booking appointment letter, if attending a booking clinic where a member of the research team 
will be in attendance. Women will be asked to indicate to a receptionist if they are agreeable to being 
approached by the research team while attending booking clinic. Women in NI commonly self-refer to maternity 
services resulting in early presentation to the maternity hospital and less GP input.     
Women will also be recruited within NI using posters around the Royal Jubilee Maternity Hospital (RJMH) and 
the Fertility Clinic.  All participants will be receiving antenatal care within the Belfast Trust.    
Women will be able to contact the research team via the contact details provided on the invitation letter prior 
to their booking appointment.  When attending the booking clinic women will be approached by a member of 
the research team and any questions they may have will be answered. If agreeable, the consent form will be 
completed, and research bloods taken as well as the first urine sample collected. 
 
3.1.3 
Study design 
 
This will be a randomised controlled trial of cows’ milk provision, along with education around iodine nutrition, 
compared with education alone, on iodine nutrition in pregnancy and the puerperium.  A total of 160 women 
will be recruited in early pregnancy.  The randomisation will be stratified based on current use of iodine-
containing supplements and performed using a predetermined randomisation schedule. 
  
 
 
 
 
 
 
 
 
 
 
Figure three: Figure indicating intervention groups 
 
 
 
Women will be recruited at 6-16 weeks gestation based on dates of last menstrual period (LMP) and confirmed 
on scan at booking clinic.  They will be provided with a participant information sheet (PIS) along with the 
invitation letter included with their booking clinic appointment. A researcher will be available in person at the 
booking clinic, via telephone or by email to answer questions throughout. During the booking clinic, women who 
are willing to participate will complete a consent form.  They will then have research bloods taken, along with 
their routine antenatal bloods, and provide the first urine sample.  Once the consent form has been completed 
the participant has been enrolled in the study and will be assigned an identification number. Following 
attendance at the booking clinic, they will then be sent an email containing a pseudonymous link to the Qualtrics 
platform to complete the initial questionnaires: demographic questionnaire (including information about 
current use of iodine containing supplements), iodine specific food frequency questionnaire (FFQ) and iodine 
knowledge questionnaire.  The participant will also be asked to complete a four-day food diary.  This will be 
returned by post; a pre-paid envelope will be provided. 
 
All participants will receive the British Dietetic Association (BDA) iodine factsheet by post and email.  If the 
participant is randomised to receive milk supply contactless delivery will be arranged.  Milk will be supplied for 
a total of 12 weeks (‘the intervention period’) at a volume of a pint/day (4 L/week) for the participant along with 
2 L/week for their family if appropriate.  On receipt of the first urine sample and all questionnaires women will 
be provided with £20 shopping voucher. 
 
Women attend for their booking appointment at around 12 weeks gestation as part of routine antenatal care.  
At this time routine bloods for clinical care are obtained.  We will use this opportunity to take 10ml of blood 
from participants for thyroid function tests (TFTs) and for storage.  If TFTs are found to be abnormal, using local 

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trimester specific values, the participant will be excluded from the study and data collected to that point 
removed.  Access to specialised endocrine input will be available if required for management of thyroid function.  
The participant’s general practitioner will be informed, along with the team providing antenatal care.  Results 
will be accessed using Labcentre and the research code used to label all blood samples taken for this study. 
 
After the intervention period of 12 weeks participants will be asked to complete an online FFQ and return a 
second urine sample by post or by contactless, doorstep, collection. Depending on gestation at recruitment this 
will be between 18-28 weeks gestation.  Approximately six weeks (+/- one week) after the intervention period a 
further urine sample will be collected by post, or by contactless, doorstep, collection along with an online FFQ. 
 
Finally, between 6-12 weeks post-partum women will be asked to provide a final urine sample, again by post or 
by contactless, doorstep, collection. They will also be provided with a ‘nappy pad’ to collect a sample of urine 
from their child.  A final online FFQ will be complete along with an iodine knowledge questionnaire.  A four-day 
food dairy will be completed and returned by post. 
 
When all data collection has been completed women will receive another £40 shopping voucher.  Women who 
have been involved in the milk intervention will also be invited to participate in the semi-structured interviews. 
 
 
Figure four: Summary of data collection throughout the study. 
 
 
 
6-16 weeks gestation
Recruitment
• Urine sample
• Demographic questionnaire
• FFQ
• Knowledge questionnaire
• Four-day food diary
18-28 weeks gestation
End of Intervention
• Urine sample
• FFQ
5-7 weeks after the intervention period
3rd Trimester
• Urine sample
• FFQ
6-12 weeks after delivery
Post-partum
• Urine sample from mother and baby
• FFQ
• Knowledge questionnaire
• Four-day food diary

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3.1.4 
Eligibility criteria 
3.1.4.1 Inclusion criteria 
 
Women at 6-16 weeks pregnant estimated by LMP. 
 
Women receiving antenatal care within Belfast Health and Social Care Trust. 
 
3.1.4.2 Exclusion criteria 
 
Women with known thyroid disease currently taking thyroid medication 
 
Women with type one diabetes (as this may alter urinary iodine secretion) 
 
Women under the age of 18 years 
 
Those unable to provide informed consent 
 
Women with abnormal thyroid function test at booking appointment. 
3.1.5 
Laboratory methods 
 
All biological samples will be processed and stored within the Centre for Public Health, QUB.  Samples will be 
stored in temperature-monitored -80C freezers.  The risk of contamination with urinary dipsticks will be 
eliminated as samples are being sent directly to the laboratory rather than being collected from a clinical setting.  
Infant samples will be collected using nappy pads which can also be returned by post.   
Urinary iodine concentration (UIC) will be measured alongside creatinine to correct for dilution.  
UIC will be measured using a multiplate persulphate digestion method followed by Sandel-Kolthoff colorimetry 
and expressed as µg/L.  Samples will be analysed in triplicate with the limit of detection at 10µg/L.  The 
laboratory is registered and participated with the Ensuring the Quality of Urinary Iodine Procedures (EQUIP) 
quality assurance programme in the UC Centers for Disease Control and Prevention.  Urinary creatinine 
concentration will be measured using an ILAB 600 chemistry analyser (Werfen, UK) using the Jaffe rate method. 
Blood samples taken at the participant’s booking appointment will be used to measure TFTs (free thyroxine and 
thyroid stimulation hormone) at the laboratory within the Belfast Health and Social Care Trust (BHSCT).  
Abnormal results, according to local trimester specific reference ranges, will exclude the participant from the 
study and she will be referred for appropriate clinical treatment.  Blood will also be drawn for storage to explore 
other markers of thyroid function in the event of a positive study (thyroglobulin, selenium and thyroid 
antibodies).  This is in-keeping with other iodine studies of this kind and will help generate future research 
hypotheses. 
3.1.6 
Outcome measures 
 
 
Proportion of the maternal cohort who achieve WHO urinary iodine concentration (UIC) of ≥ 150µg/L on early 
morning spot urinary sampling at 12 weeks post intervention i.e. at 18-22 weeks gestation.  
 
Knowledge regarding iodine intake in the diet in pregnancy and into postpartum  
 
Intake of iodine rich foods at 29 weeks and postpartum in those who breastfeed 
 
Proportion of offspring with adequate UIC levels at 6-12 weeks old 
 
3.1.7 
Statistics 
 
3.1.7.1 Power calculation 
 
Sample size has been determined to give power of 80% to detect a 25% difference in UIC.  We have allowed for 
non-completers based on drop out rate from previous dietary intervention studies. 
 
3.1.7.2 Statistical analysis 
 
In keeping with our other published data estimates of the proportion of iodine deficient samples will be 
obtained, and 95% confidence intervals calculated. The proportion of women achieving iodine sufficiency 
(defined by UIC ≥150µg/L after 12-week intervention period) in each group will be compared, with more complex 
analyses adjusting for baseline data should this be indicated by balance of groups at baseline. SPSS for windows, 
version 27 will be used for all analyses, and analyses will be directed by a medical statistician within the Centre 
for Public Health at QUB. 
 

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3.2   Semi-structured interviews 
 
 
3.2.1 
Study flow chart 
 
 
3.2.2 
Recruitment 
We plan to recruit from: 
 
The 160 participants from the main study to seek their views both before and after the intervention. 
 
Women who have shown an interest in the study but who are ineligible because of barriers to iodine intake e.g. 
veganism, lactose intolerance, strongly held views on health and nutrition and unpalatability of dairy products. 
 
Women who have approached our team because of our advertisement of the study and who, on reflection, do 
not wish to participate in the main study because of the inconvenience but consent to be interviewed as a one-
off participation. 
 
Women will be recruited from the general population through posters in the RJMH and Fertility Clinic at RVH 
 
Women self-referring to RJMH will be sent an invitation letter with the confirmation of their booking 
appointment.  This method of recruitment has previously been used successfully. 
 
 
 
 
Recruitment
• Women recruited
• Currently pregnant or child under 3 years
• Those not able to be involved in RCT (e.g. lactose intolerant, vegan)
• Advertisements on social media (mumsnet etc)
Study
• One-to-one interview
• Continue until data saturation
• Interviews carried out over the telephone or via secure 
teleconferencing facilities
Analysis
• Thematic analysis of anonymous transcripts 
Dissemination
• Results published in peer review journals
• Results shared with relevant professional bodies and policy makers
Informed consent 

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3.2.3 
Eligibility criteria 
 
3.2.3.1 Inclusion criteria 
 
Pregnant women  
 
Women with child under 3 years old 
 
3.2.3.2 Exclusion criteria 
 
Women under the age of 18 years 
 
Those unable to provide informed consent.  
 
3.2.4 
Study design 
A total of ten women participating in the trial, and ten further pregnant women, including some who are non-
milk consumers, will be recruited, although numbers may be smaller if data saturation has been achieved. 
Women will be asked to participate in a one-to-one semi-structured interview.  The interview will be conducted 
based on a topic guide, which will explore current knowledge, attitudes and perceived barriers to iodine intake 
during pregnancy and into the postpartum period, and preferred education communication methods. 
 
3.2.5 
Data collection 
 
Interviews will be carried out via the telephone or using secure teleconference applications.   Interviews will be 
audio recorded and transcribed verbatim.  Transcripts will be anonymous, and the audio recording destroyed.  
Thematic analysis will be used to identify and synthesise participant views.  Contact details and consent forms 
will be kept in a locked filing cabinet.  Anonymous transcripts used for thematic analysis will be stored in a 
password-protected folder on an encrypted laptop. 
 
Data saturation will be confirmed by two members of the research team reviewing the anonymous transcripts 
and agreeing that no new themes are emerging. 
 
3.2.6 
Outcome measures 
To reach data saturation allowing for meaningful conclusions to be drawn from the semi-structured interviews, 
with 20 women recruited initially exploring: 
 
barriers to increased iodine intake in pregnancy, 
 
for those participating in the trial, changes in these barriers over the course of the trial, 
 
preferred methods of education around nutrition during pregnancy. 
 
4.0  
Data Management 
 
 
 
 
4.1  
RCT 
  
Consent forms completed via Qualtrics will be downloaded and stored in a dedicated, password protected 
folder.  Qualtrics software allows for data to be collected using personalised links while using the participant ID 
to pseudonymise the data.  Data collected in the questionnaires on Qualtrics will then be exported to Microsoft 
Excel.  Qualtrics is GDPR compliant and is password protected. 
Completed four-day food diaries will be stored in a fire-proof filing cabinet in a secure office.  The relevant 
information will be transferred to an anonymous spreadsheet for analysis.   
4.2  
Semi-structured interviews 
Consent forms completed and returned by email will be moved to a dedicated research folder and deleted from 
the inbox where they would be associated with contact details.   
Audio recordings of the interviews will be kept in a locked office and transcribed at the earliest opportunity.  
Transcripts will be anonymous.  These will be stored on an encrypted laptop in a password protected folder.  

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Data will only be accessed by the necessary members of the research team.  Data will be stored for 5 years in 
line with the policy of Queen’s University Belfast. 
 
5.0  
Ethical and Regulatory Considerations 
 
The study is low risk.   
 
The dietary intervention will not result in iodine excess, even in the group of women already taking an 
iodine containing supplement.  
o 
The WHO recommends an intake of 250 µg iodine in pregnancy. 
o 
One pint of cows’ milk (568 ml) equates to approximately 140-224 µg of iodine. 
o 
Iodine in most supplements in 150 µg. 
o 
Maximum daily iodine intake 550-1100 µg(Supplements, 2020; WHO, 2007). 
o 
A NI pregnant cohort demonstrated iodine deficiency throughout all trimesters, despite 53% 
of women taking a pregnancy-related supplement containing iodine. 
o 
The SACN, has taken the position in its 2014 paper that “at a population level in the UK there 
are no concerns about excessive dietary iodine intakes”(Nutrition, 2014). 
 
The only blood sample required will be taken with routine blood tests during prenatal care.   
 
Given the ongoing COVID-19 pandemic we have removed all visits to clinical areas, instead collecting 
the urine samples and questionnaires by post or electronically.   
 
The topics discussed during interview are unlikely to lead to the disclosure of sensitive information that 
would have to be discussed with members of the healthcare team or emergency services. 
 
Interviews will be performed remotely via telephone with recording on university Dictaphones or 
secure teleconferencing application (Microsoft Teams or Skype) using application recording. 
 
6.0 
References 
 
Bath, S. C. (2019). The effect of iodine deficiency during pregnancy on child development. Proceedings of the 
Nutrition Society, 78(2), 150–160. https://doi.org/10.1017/S0029665118002835 
Bath, S. C., Combet, E., Scully, P., Zimmermann, M. B., Hampshire-Jones, K. H. C., & Rayman, M. P. (2016). A 
multi-centre pilot study of iodine status in UK schoolchildren, aged 8–10 years. European Journal of 
Nutrition, 55(6), 2001–2009. https://doi.org/10.1007/s00394-015-1014-y 
Ittermann, T., Albrecht, D., Arohonka, P., Bilek, R., de Castro, J. J., Dahl, L., Filipsson Nystrom, H., Gaberscek, S., 
Garcia-Fuentes, E., Gheorghiu, M. L., Hubalewska-Dydejczyk, A., Hunziker, S., Jukic, T., Karanfilski, B., 
Koskinen, S., Kusic, Z., Majstorov, V., Makris, K. C., Markou, K. B., … Völzke, H. (2020). Standardized Map 
of Iodine Status in Europe. Thyroid, 30(9), 1346–1354. https://doi.org/10.1089/thy.2019.0353 
McMullan, P., Hamill, L., Doolan, K., Hunter, A., McCance, D., Patterson, C., Smyth, P., Woodside, J. V, & Mullan, 
K. (2019). Iodine deficiency among pregnant women living in Northern Ireland. Clinical Endocrinology, 
91(5), 639–645. https://doi.org/10.1111/cen.14065 
McMullan, P., Hunter, A., McCance, D., Woodside, J. V., & Mullan, K. (2019). Knowledge about iodine 
requirements during pregnancy and breastfeeding among pregnant women living in Northern Ireland. 
BMC Nutrition, 5(1), 1–6. https://doi.org/10.1186/s40795-019-0285-8 
Mullan, K., Patterson, C., Doolan, K., Cundick, J., Hamill, L., McKeeman, G., McMullan, P., Smyth, P., Young, I., & 
Woodside, J. V. (2018). Neonatal TSH levels in Northern Ireland from 2003 to 2014 as a measure of 
population iodine status. Clinical Endocrinology, 89(6), 849–855. https://doi.org/10.1111/cen.13849 
Nutrition, S. A. C. on. (2014). SACN STATEMENT ON IODINE AND HEALTH. 
O’Kane, S. M., Pourshahidi, L. K., Mulhern, M. S., Strain, J. J., Mackle, E. M., Koca, D., Schomburg, L., Hill, S., 
O’Reilly, J., Kmiotek, D., Deitrich, C., Bath, S. C., & Yeates, A. J. (2018). Cow milk consumption increases 
iodine status in women of childbearing age in a randomized controlled trial. Journal of Nutrition, 148(3), 
401–408. https://doi.org/10.1093/jn/nxx043 
Phillips, D. I. W. (1997). Iodine, milk, and the elimination of endemic goitre in Britain: The story of an accidental 
public health triumph. Journal of Epidemiology and Community Health, 51(4), 391–393. 
https://doi.org/10.1136/jech.51.4.391 
Shaw, M., Nugent, A. P., McNulty, B. A., Walton, J., McHugh, M., Kane, A., Moore Heslin, A., Morrissey, E., Mullan, 
K., & Woodside, J. V. (2019). What is the availability of iodised salt in supermarkets on the Island of Ireland? 

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European Journal of Clinical Nutrition, 73(12), 1636–1638. https://doi.org/10.1038/s41430-019-0518-6 
Smyth, P. P. A., Burns, R., Huang, R. J., Hoffman, T., Mullan, K., Graham, U., Seitz, K., Platt, U., & O’Dowd, C. 
(2011). Does iodine gas released from seaweed contribute to dietary iodine intake? Environmental 
Geochemistry and Health, 33(4), 389–397. https://doi.org/10.1007/s10653-011-9384-4 
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https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/ 
Vanderpump, M. P. J., Lazarus, J. H., Smyth, P. P., Laurberg, P., Holder, R. L., Boelaert, K., Franklyn, J. A., & British 
Thyroid Association UK Iodine Survey Group. (2011). Iodine status of UK schoolgirls: a cross-sectional 
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4 
WHO. (2007). Assessment of the iodine deficiency disorders and monitoring their elimination. WHO, Geneva, 1–
107. 
WHO. (2013). Vitamin and Mineral Nutrition Information System. Urinary Iodine Concentrations for Determining 
Iodine 
Status 
in 
Populations, 
1–5. 
http://apps.who.int/iris/bitstream/10665/85972/1/WHO_NMH_NHD_EPG_13.1_eng.pdf