Web Appendix 7. Iodized Salt Use and Fortification Strategies. Batool A Haider, Aatekah Owais and Zulfiqar A Bhutta

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1 Web Appendix 7 Iodized Salt Use and Fortification Strategies Batool A Haider, Aatekah Owais and Zulfiqar A Bhutta Department of Paediatrics and Child Health Aga Khan University, Karachi, Pakistan Iodine fortification reduces the incidence of iodine deficiency disorders by 73%. 1 But these estimates are based on randomized controlled trials where demand and quality supply of the intervention commodities is ensured. Such is not the case when these interventions are scaled up into national programs. Hitches and glitches ranging from non-availability of commodities to refusal crop up everywhere. Thus even though an intervention might be the best public health commodity since the small pox vaccine in a controlled setting, proving its beneficial effect on the health of a large, scattered group of people is another matter entirely. The latter scenario creates a catch-22 for public health workers advocating the scaling up of such interventions - governments will not allocate precious public funds for an intervention that has not been proven effective on a large scale; an intervention cannot be proven effective on a large scale if there are no funds available for scale up. The compromise is a middle ground with national governments and international aid organization jointly footing the bill. This paper is an attempt to calculate impact estimates from the main large iodine fortification program reports reporting outcomes. We are attempting to provide an 1

2 evidence base for the advocacy of scaling up iodine fortification by strengthening the link between randomized controlled trials and national program Iodine: salt iodization PubMed, Micronutrient Initiative, Iodine Network, ICCIDD, and Helen Keller International websites and databases were extensively searched to locate large-scale salt fortification with iodine program reports. Only those reports which reported the effect on functional outcomes were included. In many cases, only the abstracts were available, and have been used to extract the outcomes of the programs. Due to the varied contexts of each report in terms of methods used, functional outcome reported etc., the effect of fortification is reported as a range. For example, if one country reported a decrease of 10% and another a decrease of 15% for the same outcome, a cumulative effect ranging from 10-15% is reported as the effect of scaling up of salt iodization. The functional outcomes are goiter prevalence and median urinary iodine excretion for iodine. Eight studies on salt iodization from seven countries and one region (comprising of 13 countries) were included in the analysis. The following table summarizes the impact of large scale salt iodization programs for each country. 2

3 Country/ Region Coverage Participants Impact of scaling up iodized salt coverage China 2 93% Population sample Median UI < 100 in only one province Croatia 3 90% School children Normal thyroid volumes; median UI = 140 microg/l Latin America 4 86% School children aged 6-12 y Median UI > 100 microg/l in all but one of the 13 countries. Lesotho 5 69% Women aged 15 to 30 y and primary school children aged 8 to 12 y Median UI = microg/l for children and microg/l for women Morocco 6 41% School children Median UI improved to 169 microg/l from 17 microg/l Papua New 95% Children 6-12 y Guinea 7 Poland 8 43% School children aged 6-15 y 63.8% School children Uganda 9 aged 6-12 y TGR = total goiter rate; UI = urinary iodine 52.8% of children had UI <50 microg/l Goiter prevalence decreased by almost two-thirds - from 14.5% to 5.2% Median UI increased from 56 microg/l to 103 microg/l TGR decreased by 19% - from 74.3 to 60.2% Visible goiter decreased by 23 % - from 39.2 to 30% The effectiveness of scaling up iodized salt coverage is apparent: goiter prevalence decreased by 19-64% in children. Except for one province in China and one country in Latin America, all programs reported normal median urinary iodine excretion levels (> 100 microg/l) in women and children after salt iodization was declared mandatory. Croatia has eliminated iodine deficiency disorders, reporting normal thyroid volumes and urinary iodine levels. 3

4 Kazakhstan is another example of a successful salt iodization campaign. In 1999 prevalence of iodine deficiency was 60% with only 29% of the households consuming iodized salt. Public awareness programs and availability of iodized backed by government legislation have dramatically successful. Today, 94% of the households are using adequately iodized salt, and unpublished figures put iodine deficiency prevalence at 0%. 10 The case of Papua New Guinea (PNG) is different. Although endemic cretinism and goiter have disappeared from the highlands of PNG, almost 53% of children are suffering from moderate to severe iodine deficiency even with very high coverage of adequately iodized salt. Temple et al 7 propose a cultural reason for this paradox. The salt intake of this population is low, probably because the intake of processed foods is low and only a little salt is added to food during preparation. The investigators suggest cautiously increasing the iodine content of the salt used to overcome the iodine deficiency. Goh 11 summarized the elements needed for a successful salt iodization program. Taking lessons from China, Madagascar and South Africa, he concluded that measures crucial for combating iodine deficiency include raising public awareness of the disorders, ensuring easy access to iodated salt, promoting compliance in the salt industry, and monitoring and enforcement. Factors that ensure a reliable supply of iodized salt are equally important as those that create the demand for it. Governments must ensure that surveillance and enforcement mechanisms are functioning right from the time that salt 4

5 iodization is made compulsory. For sustainability during later years, the adequacy of iodine in iodated salt must be monitored, and incentives must be modified as needed to increase compliance rates in the salt industry. Once national coverage of iodated salt reaches over 90%, the government can concentrate on fine-tuning and targeting resources at areas with a low consumption of iodated salt. Iodization of Water In order to assess the impact of iodization of water on maternal and child health, literature search of the Cochrane database and Medline was undertaken with the date of last search being August Search yielded eight studies which were included for further reviewing. The studies included women and children in iodine deficient countries. Evaluation of data showed that iodization of water reduced rate of goiter by 51%-88.9%. Infant mortality decreased by 56.5% and neonatal mortality by 65.7%. Table 2 classifies the main characteristics of the selected studies. 5

6 Table 2: Characteristics of included studies. Author Year Country Setting Intervention Impact DeLong GR et China Community al Based Ren Q, et al. China Community Based Yazipo D et al Central Africa Elnagar B et al Western Sudan Squatrito S et al Northeast Sicily Community Based Community Based Community Based Maberly GF et Malaysia Community al Based Potassium iodide was added to irrigation water over a 2 to 4 week peroid beginning in kg in Long Ru, 80 kg each in Bakechi and Tusala districts Iodine supplementation of irrigation water (Neonatal and infant mortality rates were obtained from official records in three counties from 1988 to 1999, and analyzed by a logistic regression model) Iodination of water with sodium iodide incorporated into silicone matrices, placed in 198 water wells Iodination of water using silicon matrices containing 30% sodium iodide placed in polyethylene baskets in 4 villages using wells or hand pumps. Iodination of the water supply was done using a streamsplitting device that diverts a controlled fraction of the total water flow to a canister containing iodine crystals, where the water becomes saturated with iodine (approximately 300 mg/liter) before returning to the main stream. 15-month interruption and since resumption at a level of /- 5 micrograms/liter. An iodinator was fitted to the existing gravity-fed watersupply Both infant and neonatal mortality decreased by half in all three treated township areas. Infantmortality rates decreased in the treated areas of Long Ru (mean [SD] 58.2 [4.4] per 1000 births to 28.7 [7.1] per 1000 births), Tusala (47.4 [12.4] per 1000 births to 19.1 [1.5] per 1000 births), and Bakechi (106.2 [9.5] per 1000 births to 57.3 [7.3] per 1000 births). The odds ratio of infant mortality decreased 56.49% and neonatal mortality 65.71% respectively after iodination Twelve months after iodination of wells, the overall prevalence of goiter fell to 44.5% (p < ) and that of visible goiter to 2.5% (p < ). The median urinary iodine concentrations increased significantly from 0.19, 0.20, 0.19, 0.11 to 1.20, 1.10, 0.37, 0.30 mumol/l in the four villages, respectively. Rate of goiter decreased from 69% to <25%. Goiter prevalence of 55% in school children declined to 6.1% by April Daily urinary iodine excretion had increased to /- 6.5 (SEM) micrograms. Serum thyroid-related hormone concentration was (pretreatment vs. November-December 1983) TSH, 3.7 +/- 0.2 vs /- 0.1 microu/ml; change being statistically significant. Within nine months, the prevalence of goiter had reduced from 61% to 30%, with 79% of goiters 6

7 Pichard E et al Mali Community Based Michalud P et al Central Chile Community Based Iodinated silicone and sodium polymers placed in bore wells Equipment efficiently and economically adds 0.5 mg of elemental iodine per liter of water to render it potable showing visible reduction in size. After iodination, circulating TSH concentration was generally undetectable (less than 0.1 mu/l). Goiter was present in 43.3% of the children in the supplemental iodine group and in 69.2% of controls. After one year, 36% of the goiters had resolved in the supplement group. In the unsupplemented village, 21 new cases of goiter occurred, for an annual incidence of 40%. Nine children (7%) had a diffuse goiter. Median urinary iodine excretion was 158 micrograms/dl. During the period of iodine water supplementation there were 47 births in the zone. All newborns had normal TSH values and none had goiter. 7

8 References: 1. Mahomed K, Gülmezoglu AM. Maternal iodine supplements in areas of deficiency. Cochrane Database Syst Rev 1997, Issue 4. Art. No.: CD DOI: / CD Zhao J, van der HF. Progress in salt iodization and improved iodine nutrition in China, Food Nutr Bull 2004;25(4): Kusic Z, Jukic T. History of endemic goiter in Croatia: from severe iodine deficiency to iodine sufficiency. Coll Antropol 2005;29(1): Pretell EA, Delange F, Hostalek U, et al. Iodine nutrition improves in Latin America. Thyroid 2004;14(8): Sebotsa ML, Dannhauser A, Jooste PL, Joubert G. Iodine status as determined by urinary iodine excretion in Lesotho two years after introducing legislation on universal salt iodization. Nutrition 2005;21(1): Zimmerman MB, Moretti D, Chaouki N, Torresani T. Introduction of iodized salt to severely iodine-deficient children does not provoke thyroid autoimmunity: a oneyear prospective trial in Northern Morocco. Thyroid 2003; 13(2): Temple V, Mapira P, Adeniyi K, Sims P. Iodine deficiency in Papua New Guinea (sub-clinical iodine deficiency and salt iodization in the highlands of Papua New Guinea). J Pub Health 2004; 27(1): Golkowski F, Huszno B, Trofimiuk M. et al. Prevalence of goiter in schoolchildren- -a study on the influence of adequate iodine prophylaxis in Poland. J Endocrinol Invest 2003;26(2 Suppl): Bimenya GS, Olico O, Kaviri D, Mbona N, Byarugaba W. Monitoring the severity of iodine deficiency disorders in Uganda. Afr Health Sci 2002;2(2): International Herald Tribune (IHT): Last accessed Dec. 20th, Goh CC. Combating iodine deficiency: lessons from China, Indonesia, and Madagascar. Food Nutr Bull 2002; 23(3): Ren Q, Gr D, Cao X. et al. Effect of environmental supplementation of iodine on infant mortality and growth in children in Xinjiang, China. Zhonghua Li Xing Bing Xue ZA Zhi 2002; 23(3): DeLong GR, Leslie PW, Wang SH. et al. Effect on infant mortality of iodination of irrigation water in a severely iodine-deficient area of China. Lancet 1997; 350(9080): Yazipo D, Ngaindiro LF, Barriere-Constantin L. et al. Effectiveness of a water iodination system for preventing iodine deficiency disease in Central Africa. Sante 1995;5(1): Elnagar B, Eltom M, Karlsson FA, Bourdoux PP, Gebre-Medhin M. Control of iodine deficiency using iodination of water in a goiter endemic area. Int J Food Sci Nutr 1997;48(2): Squatrito S, Vigneri R, Runello F, Ermans AM, Polley RD, Ingbar SH. Prevention and treatment of endemic iodine-deficiency goiter by iodination of a municipal water supply. J Clin Endocrinol Metab 1986;63(2):

9 17. Maberly GF, Eastman CJ, Corcoran JM. Effect of iodination of a village watersupply on goitre size and thyroid function. Lancet 1981;2(8258): Pichard E, Soula G, Fisch A. et al. Prevention of iodine deficiency disorders in children in the rural African zone. Ann Pediatr 1992;39(2): Michaud P, Tellez R. Thyroid function in a population with an extra iodine intake. Rev Med Chil 1998;126(2):