Evaluation of the iodine deficiency disorders control program in Lesotho
Sebotsa, Masekonyela Linono Damane
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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.