Global iodine deficiency lecture prepared for second year medical students as a means to introduce them to an endocrinological public health issue.

1. Northwestern University Feinberg School of Medicine
Global Iodine
Deficiency
Endocrine–Health and Society
Daniel Toft, MD

2. Iodine Deficiency
Iodine function: component of thyroid hormones (T3 and T4)
which regulate a variety of processes, including:
•Metabolic rate
•Heart rate
•Temperature
•Mental function
Signs and symptoms of iodine deficiency:
•In adults/children: hypothyroidism and goiter (thyroid gland hyperplasia
due to elevated TSH levels)
•Congenital hypothyroidism (in fetuses of affected mothers): intellectual
impairment, short stature, speech and hearing loss
Beth Doerfler, RD

3. Iodine Deficiency
Food sources: depends on the iodine content of the
soil on which food was raised; good natural sources
are seafood and seaweed, and in the U.S., iodized
salt, processed foods and dairy products are iodine-rich
Risk factors for deficiency: iodine-poor soil
(mountainous areas like Switzerland and the Andes,
China), excessive consumption of foods containing
goitrogens (which impair iodine absorption), such as
cassava (as in Zaire, the Congo)
Beth Doerfler, RD

4. In 2014 iodine deficiency remains a major
worldwide public health problem
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree

5. Iodine deficiency is an important health
issue for my patients
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree

6. Iodine deficiency may impact my health
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree

7. Goiter
Beth Doerfler, RD

8. Goiter
Himalayas

9. Congenital Hypothyroidism

10. Congenital
Hypothyroidism
Beth Doerfler, RD

11. Congenital Hypothyroidism
Bolivia Pakistan Tanzania

13. The Developing Brain Needs T4
T4
from mother
cochlea
Cerebral cortex
Subarachnoid pathways
Corpus callosum
Eye
Face
from child
Myelination
Cerebellum
Dentate of hippocampus
0 1 2 3 4 5 6 7 8 Birth

14. Chicago is in the “Goiter Belt”
Defects Found in Drafted Men (Love 1920)

15. A brief history of goiter
• 1813 Iodine isolated from seaweed
• Theodor Kocher (1841-1917), who performed over 5000
thyroidectomies for goiter, recognized post-op myxedema in his
patients
• 1873 children in Albi, France treated with 7.5 mg of iodine daily for
75 days with clinical improvement in goiter
• 1893 Thyroid extracts found to be useful in treating myxedema
• 1890s Baumann and Roos isolated “thyroiodine” from the thyroid
finding it contained 10% iodine
• Osler writes in the 1900s that the cause of goiter and the function of
the thyroid are still unknown
J. Nutr. 135: 675–680, 2005

17. • 1905 David Marine receives his MD from Johns Hopkins
• 1907 publishes on the iodine content of goitrous dogs vs
normal animals finding lower iodine content in goiters
• He began treating patients in his clinic with iodine and
noted improvement in goiter
• Cleveland school board rejects his request to begin
treating children – “You’ll poison our children”
• 1916 with the help of Kimball Akron, OH agrees to a trial
of iodine supplementation to its schoolchildren

18. Marine And Kimball’s Seminal
Work In Akron, OH
J. Nutr. 135: 675–680, 2005

19. “This section of the country…
is known for the great
number of goiter cases,
and a large percentage of
the children in the schools
have enlarged thyroids.”
“Iodine is gone from the land
here and therefore from
the water.”

20. “In Akron, O., some very fine
results have been obtained
by giving [iodine] to school
children. It was given over
a period of ten years and
the results watched.
One half of the 10,000
children were given it twice
a year. Among those to
whom it was administered
who were in a normal
condition, not one
developed goiter.”

21. The Problems:
There is widespread dietary iodine deficiency
•One-half to two-thirds of the world population at risk
In affected populations, goiter and cretinism in a
few coexist with cognitive deficits in all
•In populations where >5% of school children have goiter,
the cognitive performance among apparently healthy
individuals is shifted downward by 10 - 15 IQ points

22. The Solution:

23. The Solution:
Universal Salt Iodization

24. Key Components of IDD Elimination
Salt Iodization
Strategy
Oversight
Advocacy & Evaluation &
Social Mobilization Surveillance

25. Advocacy & Social Mobilization
• Accepting the magnitude of the problem
• Overcoming some resistance to universal salt iodization
• Establishing the safety of potassium iodate
• Setting adequate and safe salt iodine levels
• Salt is not an unhealthy product
• Iodization is enrichment of a commonly eaten food
• Support large companies also, not only the cottage
industry
• Focus first on areas where success is attainable, not the
poorest and most remote

26. Strategy Oversight:
The Iodine Network
A global coalition of public, private, international and civic organizations
is championing the sustained elimination of IDD through USI. Current
members of the network are:
•China National Salt Industry
Corporation
•EU Salt
•Emory University
• Global Alliance for Improved Nutrition
(GAIN)
• International Council for Control of
Iodine Deficiency Disorders (ICCIDD)
• Kiwanis International
• Salt Commissioner to the Government
of India
•Micronutrient Initiative
• Salt Institute
• Tata Chemicals
•US Centers for Disease Control
•UNICEF
• World Health Organization
• World Food Programme

27. Advocacy & Social Mobilization
Unicef data

28. In the US, is iodization of salt legally
mandated?
A. Of course
B. Of course not

29. Number Of People And Percent Of Region
At Risk Of Iodine Deficiency (TGR > 5%)
And Affected By Goiter In 1993
WHO Region Population At Risk Population Affected by Goiter
Millions % of Region Millions % of Region
Africa
Americas
E. Mediterranean
Europe
Southeast Asia
W. Pacific
181
168
173
141
486
423
32.8
23.1
42.6
16.7
35.9
27.2
86
63
93
97
176
141
15.6
8.7
22.9
11.4
13
9.0
Total 1,572 28.9 655 12
Global prevalence of iodine deficiency disorders (1993)
WHO Micronutrient deficiency information system (MDIS) working paper no. 1

31. “It can do no harm as I see it
and its use may do much
good.”

32. Deaths from exophthalmic goiter,
1920-1930
The Economic Effects of Micronutrient Deficiencies:
The case of iodine.” by Dimitra Politi, Ph.D., Brown University, 2010.

33. FIGURE2 A comparison of the number of operations for toxic
goiter carried out at Henry Ford Hospital in Detroit in the years before
and after the introduction of iodized salt in Michigan in 1924 (-E-); also
the number of cases presenting with thyrotoxicosis at Launceston
General Hospital before and after the iodization of bread in Tasmania
began in 1966 (-F-). The year of introduction is in each case classed
as “1”.
J. Nutr. 135: 675–680, 2005

34. Salt Iodization
Russia
•Began iodization efforts in 1950s and achieved success
•Dissolution of USSR: fragmentation and collapse of iodization program
•Small progress recently but household consumption still very low
China
•Premier committed to goal of IDD elimination 1991
•High level advocacy meeting 1993 launched USI program
•Over 90% coverage within a decade
India
• Rapid progress 1986-2000 once iodization open to the private sector
• Lifting of ban on sale of non iodized salt in 2000 led to significant drop in
production of iodized salt – subsequently recouped when ban was
reinstituted

36. Lessons Learned:
Education & Social Mobilization
• As visible forms of iodine deficiency (goiter/cretinism) regress the focus is
on less visible impacts especially brain damage. Ongoing communication
efforts are essential.
• Tailor messages to different audiences with specific calls to action
• Understand common wisdoms & correct misinformation and educate
public
• Integrating updated IDD info into technical & education materials of food
inspection, health, and education curriculums
• Public education serves to solidify support for IDD elimination and create
a demand for iodized salt

37. Evaluation & Surveillance
• WHOI 2007 Resolution: Efforts to eliminate IDD require
continuous monitoring and oversight and require Member
States to establish mechanisms for monitoring iodine
nutrition and reporting on their progress.
• UIE trends in school-aged children to be complemented
with iodine status of pregnant and lactating women.
• Monitoring of iodine status should not only check for
deficiency but also highlight excess.

38. Degree of public health significance of iodine nutrition based on median urinary iodine: 1993-2006
Source:
de Benoist B et al. Iodine deficiency in 2007: Global progress since 1993.
Food and Nutrition Bulletin, vol 29, no. 3, 195-202, September 2008.
Category of public health significance
(based on median urinary iodine)
Moderate iodine deficiency (20-49 μg/l)
Mild iodine deficiency (50-99 μg/L)
Optimal (100-199 μg/l)
Risk of iodine induced hyperthyroidism (200-299 μg/l)
Risk of adverse health consequences (>300 μg/l)
No data
The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever
on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities,
or concerning the delimitation of its frontiers or boundaries.
Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.
© WHO 2009. All rights reserved

39. Overview of Global Progress
• Globally, 70% of households are consuming adequately
iodized salt.
• 34 countries have achieved USI and another 28 are
close to the goal.
• 84 million infants are protected annually from the risk of
IDD.
• More than 120 countries are implementing USI
programs.
• The number of countries where IDD remains a problem
has dropped to 47.
UNICEF, May 2008

40. Which best describes your
eating habits?
A. I rarely eat a home
cooked meal
B. I can cook but generally
eat out
C. I cook most of my meals
D. I cook and prefer kosher
or sea salt

41. Emerging Issues: Processed Foods
• Given expanded consumption of process foods, programs
relying upon fortification of table salt alone may not be
adequate.
• Food processors reluctant to use iodized salt – unfounded
concerns about effects on organoleptic properties of foods
• Iodine intake may also be reducing due to other changes
e.g. decreased use of iodophors in the dairy industry
• Trade harmonization to mandate use of iodized salt in
processed foods to address inter-country variations in
micronutrient recommendations may offer a solution.

42. Emerging Issues: I Insufficiency

43. Effect of inadequate iodine status in UK
pregnant women on cognitive outcomes in
their children
• Urinary iodine levels on 1040 first trimester
singleton pregnancies were measured
• 646 (!) were iodine insufficient (urinary iodine
less than 150 μg/g creatinine)
• The IQ at 8 years and reading ability at 9 years
of the children were analyzed for an association
with maternal iodine sufficiency
Lancet 2013; 382: 331–37

44. Effect of inadequate iodine status in UK
pregnant women on cognitive outcomes in
their children
After adjustment for confounders, children of women with an
iodine-to-creatinine ratio of less than 150 μg/g were more
likely to have scores in the lowest quartile for
verbal IQ (odds ratio 1·58, 95% CI 1·09–2·30; p=0·02)
reading accuracy (1·69, 1·15–2·49; p=0·007)
reading comprehension (1·54, 1·06–2·23; p=0·02)
Lancet 2013; 382: 331–37

45. Why are UK women iodine
deficient?

47. US Women are Iodine Insufficient
Thyroid. 2013 Aug;23(8):927-37

48. More Salt May not be the Answer
Salt consumption n % Urinary I p
White Never or rare 142 27 110 .07
Not often 188 27 144
Often 183 36 148
n % Urinary I p
Black Never or rare 77 24 117 .2
Not often 97 30 132
Often 136 46 116
Hispanic Never or rare 78 17 154 .2
Not often 128 27 542
Often 255 56 165
Thyroid. 2013 Aug;23(8):927-37

49. Neither is Seafood
n % Urinary I p
Fish/shellfish
consumption
n % Urinary I p
White Yes 353 71 144 0.6
No 159 29 134
Black Yes 244 82 119 0.5
No 66 18 123
Hispanic Yes 339 73 166 0.03
No 128 27 146
Thyroid. 2013 Aug;23(8):927-37

50. Dairy consumption matters
Dairy consumption n % Urinary I p
White Never or rare 149 27 111 0.0001
Not often 167 31 133
Often 216 42 189
Black Never or rare 126 40 111 0.0009
Not often 89 28 109
Often 101 32 151
Hispanic Never or rare 153 31 134 <0.0001
Not often 133 27 163
Often 210 42 185
Thyroid. 2013 Aug;23(8):927-37

51. Group A: ID areas, no iodine intervention
Group B: ID areas, uncontrolled iodized salt
Group C: ID areas, iodine supplements @ pregnancy or birth
Ming Qian et al, Asia-Pacific J Clin Nutr 2005

52. Areas of Controversy
Should iodine be a required component of prenatal
vitamins?
Should iodine and thyroid hormone testing be
standard preconception/during pregnancy?

53. What percentage of the 200+
prenatal vitamins in the US
contain iodine?
A. 0 %
B. 20 %
C. 50 %
D. 80 %
E. 100

54. Conclusions

55. Conclusions
• Iodine Deficiency Disorders are widespread in the world
affecting millions of people with a range of physical and
mental abnormalities.
• Universal Salt Iodization (USI) of all human and animal salt
is the global strategy for elimination of severe iodine
deficiency.
• While tremendous progress has been made to make salt
iodization universal, 2 billion people are still at risk in the
world

56. Conclusions
• Government Commitment is key for USI
• IDD knowledge needs to be embedded into health sector
infrastructure
• Continued advocacy efforts are needed particularly in
Europe
• Expand iodization to include salt used in processed foods
• RDA is 150 μg/day for adults; 250 μg/day for pregnant
and nursing mothers

57. In 2013 iodine deficiency remains a major
worldwide public health problem
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree

58. Iodine deficiency is an important health
issue for my patients
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree

59. Iodine deficiency may impact my health
A. Strongly Agree
B. Agree
C. Somewhat Agree
D. Neutral
E. Somewhat Disagree
F. Disagree
G. Strongly Disagree