iodine def

7/28/2019 Iodine Def

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Iodine deficiency disorders

Iodine is an essential component in thyroidhormone production

Thyroid hormone regulates basic metabolism

:energy consumption, cellular activity, growthand in particular brain development.

Hypothyroidism: slow, cold, sluggish brainfunction, short stature, mental and motordevelopment delayed or slowed. In extremesgeneral neurological development delayed.


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Hormone regulationHypothamalus

TSHT3 T4

Hypofysis

- SomatostatinTSHRF

T4 T3

I pool


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Hormones and iodine deficiency


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Spectrum of disease

Table 1. The Spectrum of Iodine Deficiency Disorders, IDD.

Fetus Abortions StillbirthsCongenital anomalies

Increased perinatal mortality

Endemic cretinism

Neonate Neonatal goiter Neonatal hypothyroidism

Endemic mental retardation

Increased susceptibility of the thyroid gland

to nuclear radiation

Child and Goiter adolescent (Subclinical) hypothyroidism

Impaired mental function

Retarded physical development



Adult Goiter with its complications HypothyroidismImpaired mental function

Spontaneous hyperthyroidism in the elderly

Iodine-induced hyperthyroidism



Adapted from Hetzel (1), Laurberg et al. (52, 171) and Stanbury et al. (158).


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Importance of the problem


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Prevalence

1 billion persons exposed

200 million persons affected (goitres)

26 million cases of mental problems

6 million cases of cretinism


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Goitre

Increase in size four to five times distal phalanxof the thumb

Aesthetic

Compression

Related hypothyroidism: is not a compensation

cancer

Iod Basedow (hyperthyroidism) due tohyperstimulation, mutation autonomous nodules


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Iodine deficiency and the foetus

Brain development fast between 3-5 monthspregnancy and from third trimester till end ofsecond year

Maternal T4 essential for first 24 weeksFoetal T4 starts at 24 weeks

30% cord blood is of maternal origin


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Iodine and the neonate

Perinatal mortality

Infant mortality

Low birth weight

Brain development needs T4

Iodine deficiency mental retardation, retardedmotor development.

General IQ decrease of 15 Points


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Iodine deficiency and adults

Lack of energy

apathy, slow brains

goitre and mechanical complications

Nodular thyroid

hyperthyroidism

Pregnancy and cretinism


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Aethiology

Low iodine uptake. Soil dependent

erosion, wash away: deltas

Goitrogens

Manioc: linnamarin thiocyanateBlocs uptake of Iodine at the thyroid, competitive

inhibition

Traditional preparations

Konzo

Brassica family

polutants


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IDD and selenium deficiency

Se part of peripheral type I de-Iodinase (kidneyand liver)

Se deficiency: slower T4 to T3 metabolisation

Se part of Glutathion peroxidase : protector ofH2O2 damage Thyroid damage, disfunction ofthyroid

Cerebral de-iodinase is not Se dependentGlutathion peroxidase stimulates T4 production


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Iodine needs

RECOMMENDED INTAKE ug/day

0 - 6 months 35 8 ug/kg

5 ug/100ml of milk7 ug/100 kcal

6 - 12 months 45

1 - 10 years 60 100

>= 11 years 100 - 115pregnancy lactation 125 - 150


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Diagnosis of endemicity

Prevalence of goitre

Dosage of urinary iodine

TSH dosage

Prevalence of cretinism


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Prevalence of goitre

Class Description

0Absence of goitre

Ia Detectable goitre only by palpation and invisible, even when thehead is stretched. More voluminous thyroid than usual, the lobes

have a volume that is at least equal to the volume of the last

phalanx of the subjects thumb.

Ib Palpable and visible goitre when the head is stretched. Also all the

cases where there is a nodule - even when there is no goitre.

II Visible goitre when the head is in a normal position.

III Very big goitre, visible from a distance


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IODE DEFICIENCY SEVERE MODERATE MILD

Number of cases of

goitre among the

school children (6-12)

visible goitre

total goitre

> 50 %

> 10 %

20-49 %

5-9 %

10-19 %

1-5 %


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Urinary Iodine

Reflects directly intake

Is best to follow up programme response, goitretakes time to decrease in size

Samples needed are smallerTechnique is simple and not expensive

Samples can be taken easily, cheap, acceptable

and dont need conservation techniques


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Table 5. Epidemiological criteria for assessing iodine nutritionbased on median urinary iodine concentrations in school-aged children

Medianurinary

iodine

Iodine intake(g/L)

Iodine nutrition

< 20 Insufficient Severe iodine deficiency

20-49 Insufficient Moderate iodine deficiency

50-99 Insufficient Mild iodine deficiency

100-199 Adequate Optimal

200-299 More than adequate Risk of iodine-induced

hyperthyroidism within 5-10 years

following introductionof iodized salt in susceptible

> 300 Excessive Risk of adverse health consequences

(iodine-induced hyperthyroidism,

autoimmune thyroid diseases)

From WHO/UNICEF/ICCIDD (2)


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Endemic cretinism

Neurological

Severe motor and mental deficit

cerebral palsy

deafness, mutismeuthyroid

Myoedematous

Severe mental deficit

Hypothyroid, destruction of the thyroid

Iodine deficiency combined with goitrogens and Sedeficiency


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Control strategies

Supplementation: injections, oral

Fortification

changing food habits


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Supplementation

Need to start early in pregnancy

supplement women of child bearing age

Operational difficulties

Injections and hepatitis and HIV

Covers need for about 4 years injections

Oral covers needs for one year


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Fortification

Add iodine to a vehicle: salt or water

Additive must be stable, not change the carrier

No by-pass, centralised production

Need for a comprehensive approach

Packaging, evaporation

Access of all the population to the fortified food

Policy and protection of the marketWho pays?

Success story of Iran


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Food habits

Very limited approach, food reflects iodine soilcontent


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Control complications

Need for intensive follow up

Changing consumption patterns in salt

Variations in salt consumption

Transient hyperthyroidism


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iodine def

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