Evaluation of the iodine deficiency disorders control program in Lesotho
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Date
2003-05
Authors
Sebotsa, Masekonyela Linono Damane
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
The broad range of disorders in a population caused by an inadequate dietary supply of iodine
was denoted as iodine deficiency disorders (JDD), which include endemic goitre,
hypothyroidism, cretinism and congenital anomalies. When iodine deficiency is widespread,
mental retardation impedes national human resource development. Despite the known
effective control measures, 130 WHO member states have a significant JDD problem. Severe
to mild JDD have been reported in Lesotho since 1960.
The most cost-effective and sustainable intervention to eliminate JDD is the iodisation of all
edible salt. However, several countries with long standing salt iodisation programs have
reported declining levels of urinary iodine. In Lesotho, the legislation on universal salt
iodisation was promulgated in 2000. Therefore the aim of the study was to evaluate the salt
iodisation program in Lesotho in terms of process, impact and sustainability indicators. A 30 cluster national survey was conducted where the proportion to population size method
was administered. In each cluster, 30 women aged 15 to 30 years, and 30 primary school
children aged 8 to 12 years, were randomly selected. The selected women and children were
palpated and thyroid size graded according to WHOIUNICEFIICCJDD (2001) criteria and
urine samples collected. 30 salt samples were collected from these selected women, 6 samples
from 2 randomly selected retailers in each cluster, and 107 samples collected from all the
commercial entry points in the country. The salt samples were analysed using the iodometric
titration method while urine samples were analysed using the method using ammonium
persulfate according to WHOIUNICEFIICCJDD (2001) recommendations. This analysis was
performed at the Medical Research Council in Cape Town (South Africa) where the
Coefficient of Variation for urinary iodine analysis was 7.7 at a concentration of IOug/l, and
was 2.7 at a concentration of 70ppm for titration method of salt analysis. The statistical
analysis was done using the SAS program at the University of the Free State (South Africa).
A total of927 children and 930 women who were palpated, and 912 children and 924 women
who gave urine samples, were included in the analysis of the results. 930 salt samples from household level, 186 from retail level and 107 from entry point level were analysed. 3 salt
samples from entry point, 18 and 6 data sheets for urinary iodine of women and children
respectively were not included during statistical analysis. The median iodine concentration of
salt was 36.2ppm (ranging from 30.5-55.4ppm in the different entry points), 37.3ppm (ranging
from 12.4-50.2ppm in the different districts) and 38.5ppm (ranging from 29.2-43.2ppm in the
different districts) at entry point, retail level and household level respectively. At household
level only 1.6 percent used non iodised salt and 86.9 percent used adequately iodised salt. The analysis of the urine samples showed that the median urinary excretion was 214.7flg/1
(ranging from 62.9flg/1 to 302.6flg/l in the different districts) for the children and 280.1flg/
(ranging from 124.8flg/1 to 381.6flg/l in the different districts) for the women, indicating more
than adequate iodine intake according to the WHOIUNICEFIICCIDD (2001) report. The
median iodine concentration was higher in boys (219.3flg/l) than in girls (212.6flg/I), higher in
the Lowlands (256.0 flg/l in children and 329.9 ug/l in women) than in the Mountains
(99.30flg/l for children and 182.6flg/1 in women) and higher in non-pregnant women (283.0
ug/l) than in pregnant women (212.1 ug/l). In the whole country, the prevalence of goitre was
10.7 percent (ranging from 6.6% to 22.6 % in the different district) in children and 19.4
percent (ranging from 6.7% to 36.7% in the different districts) in women, which indicates
mild IDD (WHOIUNICEFIICCIDD, 2001). IDD were observed more in females (14.0%)
than in males (7.0%) and was less (4.3%) in children aged 8 than in children aged 12 years
(12.9%). In women IDD increased with age from the age group of 15 to 19 (17.3%) to the age
group of 20 to 25 (22 %) and decreased in the age group of 26 to 30 (18.4%). Similar to
urinary iodine results, IDD was observed more in the Mountains (17.7% for women and
18.1% for children) than in the Lowlands (14.3% for women and 6.7% for children). Only the urinary iodine excretion reached the WHOIUNICEFIICCIDD (2001) sustainability
goals. At household level, 86.9 percent of the households, which is slightly lower than the
recommendation of at least 90 percent, use adequately iodised salt. Out of 10 programmatic
indicators of sustainability, only 4 indicators have been attained by the salt iodisation program
in Lesotho. According to the WHOIUNICEFIICCIDD (2001) at least 8 of the programmatic
indicators should be attained for sustainable elimination ofIDD. The study demonstrates a major achievement in the household use of iodised salt and
adequately iodised salt. However, salt is not iodised according to the legislation on universal
salt iodisation in Lesotho due to under iodisation and non- uniformity of salt iodisation at the
production site. Iodine deficiency has been eliminated as a public health problem in Lesotho
and this is due to the introduction of the legislation on universal salt iodisation. This study
highlighted the effectiveness of iodised salt in increasing urinary iodine concentration.
Iodine deficiency increased with age and was higher in girls than in boys, and higher in the
Mountains than in the Lowlands. IDD elimination in Lesotho will be sustainable if more than
90 percent of the households use adequately iodised salt and the programmatic indicators such
as commitment to reassessment, political commitment, implementation of social mobilization
program and reqular monitoring are achieved by the IDD control task force. The administrative structure and activities of the IDD control task force need to be revised and
strengthened for the sustainable elimination ofIDD. The terms of reference of the committee
should be revised, budgets for the activities be drawn, new members added and trained and
responsibilities given to each member. Awareness campaigns, which will start at policy
makers' level, should be initiated. Law enforcement should be an integral part of the salt
iodisation program. Effective regular monitoring of salt iodine content at all levels with
special attention to iodisation of coarse salt is recommended together with periodic evaluation
of the iodisation program.
Description
Keywords
Goitre, Urinary iodine concentration,, Iodine deficiency disorders, Salt iodisation,, Sustainability,, Monitoring and evaluation, Nutrition disorders -- Lesotho, Iodine deficiency diseases -- Lesotho, Dissertation (M.Sc. (Dietetics))--University of the Free State, 2003