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Assessment of Iodine Deficiency Disorders using the 30
Cluster
Approach in District Kangra, Himachal Pradesh
Dr. K.S. Sohal
Dr. T.D. Sharma
Dr. Umesh Kapil
1999
Dr. K.S. Sohal
Dr. T.D. Sharma
Dr. Umesh Kapil
1. Dr. S.N. Sharma Investigator
2. Dr. N.K. Mehta Investigator
3. Mrs. Swaranlata Investigator
4. Mr. G.L. Jaryal Investigator
5. Mr. P.S. Pathania Investigator
Principal Investigators
Dr. K.S. Sohal
Dr. T.D. Sharma
Dr. Umesh Kapil
1. Dr. S.N. Sharma Investigator
2. Dr. N.K. Mehta Investigator
3. Mrs. Swaranlata Investigator
4. Mr. G.L. Jaryal Investigator
5. Mr. P.S. Pathania Investigator
Report Prepared by Technical Group
Consisting of
Dr.
K.S. Sohal
Dr.
T.D. Sharma
Dr.
Umesh Kapil
Assistant Editors
Ms. Monica Tandon
Ms. Priyali Pathak
The Research Team Members would like to thank
Director, Health Services, Himachal Pradesh for
giving us a privilege of undertaking the Iodine Deficiency Disorders survey in
the Kangra
district. We would like to thank Dr. S.N. Sharma, Dr. N.K. Mehta, Mrs. Swarnlata, Mr. G.L. Jaryal, Mrs.
P.S. Pathania and all the other Medical Officers and
Senior Paramedical staff members for their most valuable support and guidance
in implementation of the study. We would like to thank Dr. Sheila Vir, Project Officer, UNICEF,
List of Contents
Contents
Executive Summary
1. Iodine deficiency and its health
consequences
2. Socio-demographic profile of Himachal Pradesh
3. Status of IDD in Himachal
Pradesh
4. Assessment of IDD in district Kangra,
Himachal
Pradesh
4.1
Objectives
4.2
Methodlology
4.3
Results
4.4
Discussion
4.5
Conclusion
4.6
Tables
4.7
References
4.8
Appendices
5. Lessons
Learnt from IDD survey in district Kangra
CMO
Chief
Medical Officer
GSSM
Child
Survival and Safe Motherhood
GOI
Government
of
ICCIDD
International
Council for Control of Iodine Deficiency Disorders
ICDS
Integrated
Child Development Services
IDD
Iodine
Deficiency Disorders
NGCP
National
Goitre Control Programme
NIDDCP
National
Iodine Deficiency Disorders Control Programme
PPS
Probability
Proportionate to Size
STK
Spot
Testing Kit
TGR
Total
Goiter Rate
TSH
Thyroid
Stimulating Hormone
UIE
Urinary
Iodine Excretion
UNICEF
United
Nations Children’s Fund
WHO
World
Health Organisation
Executive Summary
Iodine Deficiency is an important public health problem in Himachal Pradesh. The earlier studies conducted has reported
a high prevalence of goitre in Shimla,
41.6% (1974), Kangra 32.1% (1962), Kullu 16.6% (1989), Una 41.2%
(1956), Solan 39.9% (1959). The district Kangra is a known iodine deficiency endemic area. A survey
conducted in 1956 reported a goitre prevalence of 55%
in the district. A recent pilot study (1994) in 4 blocks of the district
reported the TGR as 7%. In view of the continued prevalence of goitre in more than 5% in school age children, inspite of supply of iodised salt to entire population, the
present study was conducted to have more objective and scientifically valid
estimates of the prevalence of IDD in the district to facilitate the state
government to modify it’s
intervention activities towards elimination of IDD.
The present study was conducted i) to assess the prevalence of IDD in district Kangra and ii) to
estimate the iodine content of salt consumed by population in district Kangra. The “30
cluster” sampling methodology and indicators for assessment of IDD as
recommended by the joint WHO/UNICEF/ICCIDD Consultation were utilised for the survey. Children in the age group of 6-11
years were considered for assessment of iodine deficiency. In district Kangra, the school enrollment of primary classes was more
than 90% and hence the school approach was adopted.
The sample size of children to be surveyed was calculated
with a presumption that the prevalence
of goitre at the time of the survey was 5%. The Confidence level of 95%, relative
precision of 10% and design effect of three was considered for calculation of
sample size. Utilising these parameters a sample size
of 21,897 was obtained. In eachidentified school unit (cluster) the detailed survey
was conducted. In each school, about 730 children were surveyed. If the sample could not be
covered in one school, the adjoining school/schools were included to complete
the sample of a cluster. The clinical examination for goitre
was done by medical doctors specially trained for the survey. On the spot urine samples were collected from
every tenth child included in the study. In each cluster, about 70 casual urine
samples were collected in wide mouthed screw capped plastic bottles. Iodine was
determined by the wet digestion method. The results were expressed as mcg iodine/dl urine. In each cluster, more
than 35 salt samples were randomly collected from the families of school
children who were included in the study.
A total of 23,348 school children in the age group of 6-11
years were included in the study. The
male: female ratio of the study samples was 1:1. The total goitre
prevalence rate was found to be 12.1%.
It was found that 3.5, 3.8 and 14.2 percent of the children had urinary excretion levels of <2, 2 - 4.9,
and 5 - 9.9 mcg/dl, respectively. The median urinary iodine excretion of the
children studied was found to be 15.00 mcg/dl.
Salt with a nil iodine content was consumed by only 0.8% of the beneficiaries. About
11.9% of families consumed salt with an iodine content of less than 15 ppm.
In the present study, a total goitre
prevalence rate of 12.1% was found but
the median urinary iodine excretion of the children studied was found to
be 15.00 mcg/dl indicating that there was no biochemical deficiency of iodine
in the subjects studied. Results of the
present study indicated that the population of district Kangra
is in a transition phase from iodine deficient to iodine sufficient nutriture
and there is a need of further strengthening the system of monitoring of quality of iodised salt made
available to population to achieve elimination of IDD.
1. Iodine
Deficiency and its Health Conse-quences
About 1.5
billion people, or nearly one-third of the earth’s population, live in areas of
iodine deficiency. The iodine deficiency disorders (IDD), include irreversible
mental retardation, goitre, reproductive failure,
increased child mortality, and socioeconomic compromise. All of these results can be prevented by
sufficient iodine in the diet. Eliminating iodine deficiency is recognized as
one of the most achievable of the goals that the 1990 World
1.1 Iodine
Deficiency Disorders
Healthy humans
require iodine, an essential component of the thyroid hormones, thyroxine and triiodothyronine.
Failure to have adequate iodine leads to insufficient production of these
hormones, which affect different parts of the body, particularly muscles,
heart, liver, kidney, and the developing brain. Inadequate hormone production
adversely affects these tissues, resulting in the disease states known collectively
as the iodine deficiency disorders, or IDD. These consequences include: (i) mental retardation, (ii) other defects in development of
the nervous system, (iii) goitre (enlarged thyroid),
(iv) physical sluggishness, (v) growth retardation, (vi) repro-ductive failure, (vii) increased childhood mortality, and
(viii) economic stagnation. The most devastating of these consequences are on
the developing human brain.
Iodine
deficiency has been called the world’s major cause of preventable mental retardation.
Its severity can vary from mild intellectual blunting to frank cretinism, a
condition that includes gross mental retardation, deaf mutism,
short stature, and various other defects. In areas of severe iodine deficiency,
the majority of individuals risk some degree of mental impairment. The damage
to the developing brain results in individuals poorly equipped to fight
disease, learn poorly, unable to work effectively and/or failure to reproduce
satisfactorily.
In addition to
mental retardation, goitre is an important
consequence of iodine deficiency, in this instance, thyroid enlargement can be
viewed as an attempt to compensate for inadequate hormone production by the
thyroid, in turn a consequence of insufficient iodine for hormone synthesis. The
pituitary gland at the base of the brain secretes its own hormone - TSH
(thyroid stimulating hormone) - in response to the levels of thyroid hormone
circulating in the blood; when thyroid hormone production is low, the pituitary
secretes more TSH. This increased stimulation causes thyroid enlargement. The
resulting goitre is a marker for iodine deficiency,
and is particularly useful because it is easily assessed. While the effects on
the developing brain are the most important consequence of iodine deficiency,
the goitre is also important because it can lead to
significant morbidity from compression and altered thyroid function.
Unlike nutrients
such as iron, calcium or the vitamins, iodine does not occur naturally in
specific foods; rather, it is present in the soil and is ingested through foods
grown on that soil. Iodine deficiency results from an uneven distribution of
iodine on the earth’s crust. Ocean water contains adequate amounts of iodine
but not the salt produced from sea water. The person living near the sea and
those eating a specific species of sea fish which eats a particular variety of
sea weed and products like 'kelp' are more likely to be iodine sufficient but
these are not accessible to everyone. Soils from mountain ranges, such as the
Himalayas, Alps, and Andes, and in areas with frequent flooding, are
particularly likely to be iodine deficient. The problem is aggravated by
accelerated deforestation and soil erosion. This deficiency in the soil cannot
be corrected. The food grown in iodine deficient regions can never provide
enough iodine to the population and livestock living there. Many other areas of
the world also harbour severe iodine deficiency, such
as large parts of central Africa. Living on the sea coast does not guarantee
iodine sufficiency, and significant pockets of iodine deficiency have been
reported for example from the Azores, Bombay, Bangkok and Manila. A recent
WHO/UNICEF/ICCIDD Report estimates that currently at least 1,570 billion people
(or 29% of the world’s population) live in areas of iodine deficiency and need
some form of iodine supplementation. Most of these are in developing countries
in Africa, Asia, and Latin America, but large parts of Europe are also
vulnerable.
Iodine
deficiency thus results mainly from geological rather than social and economic
conditions. It cannot be eliminated by changing dietary habits or by eating
specific kinds of foods grown in the same area. Rather, the correction has to
be achieved by supplying iodine from an external source. This can be done in
two ways: by periodic supplementation of deficient populations with iodized oil
capsules or by fortifying a commonly eaten food with iodine. While both
strategies are effective, the iodization of salt is the common, long term and
sustainable solution that will ensure that iodine reached the entire population
and is ingested on a regular basis. Fortification of salt has been extremely
successful in eliminating iodine deficiency disorders in North America and many
parts of Europe.
In India out of
275 districts surveyed of 25 states and 4 union territories, 235 districts have
been identified as endemic for IDD. The states having a high prevalence of goitre are : Jammu & Kashmir, Himachal
Pradesh, Punjab, Haryana, Bihar, West Bengal, Sikkim,
Assam, Mizoram, Meghalaya, Tripura, Manipur, Nagaland and Arunachal Pradesh. Others include the National Capital
Territory of Delhi, Maharashtra, Madhya Pradesh and
Gujarat (2,3,4) (Appendix I).
2. Socio-Demographic
Profile of Himachal Pradesh
Himachal Pradesh is situated in the north west corner of
India, right in the lap of the Himalayan ranges. It is surrounded by Jammu and
Kashmir in the north, Uttar Pradesh in the south east, Haryana in the south and
Punjab in the west. In the east, it forms
India’s boundary with Tibet. Himachal Pradesh has a land area of 55,673 Km and population of 5,111,079. In
1991, its share of India’s total population was 6.1 percent and its share of
area as 1.7 percent. Shimla, the capital, is located
at the center of the state.
Himachal Pradesh is one of the educationally advanced
states in the country. The literacy rate for the population aged 7 years and
above is 63.54 percent, compared with 52 percent for all India. The literacy
rates are 74.57 percent for males and 52.46 percent for females in Himachal Pradesh, compared with 64 percent and 39 percent
for males and females, respectively, for the whole of India.
Basic
demographic indicators for Himachal Pradesh and India, 1981-1992
Index
|
|
Himachal
Pradesh
|
India
|
|
Population |
(1991) |
5,170,877 |
846,302,688 |
|
Percent population
increase |
(1981-91) |
20.8 |
23.9 |
|
Density
(Population/km2) |
(1991) |
93 |
273.0 |
|
Percent urban |
(1991) |
8.7 |
26.1 |
|
Sex
ratio |
(1991) |
976 |
927 |
|
Percent 0-14 years old |
(1981) |
39.6 |
39.6 |
|
|
(1991) |
36.9 |
36.3 |
|
Percent 65+ years old |
(1981) |
4.7 |
3.8 |
|
|
(1991) |
4.7 |
3.8 |
|
Percent schedule caste |
(1981) |
25.3 |
16.7 |
|
Percent schedule caste |
(1991) |
4.2 |
8.0 |
|
Percent Literate |
(1991) |
|
|
|
|
Male |
75.4 |
64.1 |
|
|
Female |
52.1 |
39.3 |
|
|
Total |
63.9 |
52.2 |
|
Crude birth rate |
(1992) |
27.9 |
29.0 |
|
Crude death rate |
(1992) |
8.8 |
10.0 |
|
Exponential growth rate |
(1981-91) |
1.89 |
2.14 |
|
Total fertility rate |
(1992) |
U |
3.6 |
|
Infant mortality rate |
(1992) |
67 |
79 |
|
Life expectancy |
(1986-90 |
|
|
|
|
Male |
U |
58.1 |
|
|
Female |
U |
59.1 |
|
Couple protection rate |
(1992) |
54.1 |
43.5 |
U
= Not available
1Based on
population age 7 and above
Source: Office of
the Registrar General (1992, 1993, 1994a, 1994b), Office of the Reghistrar General and Census commissioner (1987, 1992),
ministry of Health and Family Welfare (1991, 1992).
Himachal Pradesh’s crude birth
rate of 27.9 births per 1,000 population is lower than the All-India rate of
29.0, and similarly the crude death rate for the state (8.8 deaths per 1,000 population) was lower than
the national rate (10.0 deaths per 1,000 population). The infant mortality rate
was 67 deaths per 1,000 live births - considerably lower than that for India
(79 per 1,000 live births) for the year
1992.
District Kangra is situated
in the western side of the state and has a population of 11,74,072. The total land area covered by the district
is 5,739 i.e. 10.3% with a population density of 205 person per sq. km.
Sex ratio in the district is 1024 females per 1000 males. The crude birth rate
in the district was 23 and crude death rate was 8 as per 1991 census.
3. Status of IDD in Himachal
Pradesh
IDD are an
important public health problem in Himachal Pradesh.
The earlier studies conducted have reported a prevalence of goitre
in Shimla 41.6% (1974), Kangra
32.1% (1962), Kullu 16.6% (1989), Una
41.2% (1956) and Solan 39.9% (1959).
The district Kangra, Himachal Pradesh is a known iodine deficiency endemic area. A
survey conducted in 1956 reported a goitre prevalence
of 55% in the district (6). To ensure
adequate availability and use of iodised salt, the government of HP issued a
ban notification for the sale of
non-iodised salt for human consumption in
1962 (7). Based on the finding of
Kangra study National Goitre
Control Programme was launched (5). Under the ban
notification, iodised salt with a minimum of 30 ppm
iodine at the manufacturer’s level and 15 ppm iodine
at the consumer level, is ensured in the state (1).
A recent pilot
study (1994) reported the TGR of 7% in the 4 selected blocks of district Kangra (8). Keeping in view of the continued prevalence of
IDD in more than 5% of school age children inspite of
supply of iodised salt to all population, it was thus decided
to have more objective and scientifically valid data on the prevalence
of IDD in the district which could facilitate
the government in future to modify their intervention activities for
elimination of IDD.