Backgroud Iodine deficiency is the main cause for potentially preventable mental retardation in childhood and is still prevalent in large parts of the world. Objectives To assess the effects of iodised salt in comparison with other forms of iodine supplementation or placebo in the prevention of iodine deficiency disorders.Search strategy We searched the Cochrane Library, Medline, the Register of Chinese trials developed by the Chinese Cochrane Centre, and the Chinese Med Database. We performed handsearching of a number of journals (Chinese Journal of Control of Endemic Diseases, Chinese Journal of Epidemiology, Chinese Journal of Preventive Medicine, and Studies of Trace Elements and Health up to February 2001), and searched reference lists, databases of ongoing trials and the Internet. Date of latest search: November 2001. Selection Criteria We included prospective controlled studies of iodised salt versus other forms of iodine supplementation or placebo in people living in areas of iodine deficiency. Studies reported mainly goitre rates and urinary iodine excretion as outcome measures. Data collection amp; analysis As the studies identified were not sufficiently similar and not of sufficient quality, we did not do a meta-analysis but summarised the data in a narrative format. Main results We found six prospective controlled trials relating to our question. Four of these were described as randomised controlled trials, one was a prospective trial that did not specify allocation to comparison groups, and one was a large population-based study comparing different interventions. Comparison interventions included non-iodised salt, iodised water, iodised oil, iodation with potassium iodide versus potassium iodate. Numbers of participants in the trials ranged from 35 to 334; over 20 000 people were included in the population-based study. There was a tendency towards goitre reduction with iodised salt, although this was not significant in all studies. There was aim an improved iodine status in most studies (except in small children in one of the studies), although urinary iodine excretion did not always reach the levels recommended by the WHO. Reviewers’ conclusions The results suggest that iodised salt is an effective and safe means of improving iodine status. However, high quality controlled studies are needed to address questions of dosage and best means of iodine supplementation in different population groups.
Objective To assess the efficiency of iodised salt on iodine deficiency disorders. Methods we searched MEDLINE (1996 to December 2009), EMbase (1974 to December 2009), The Cochrane Library (Issue 4, 2009), Current Controlled Trials, The National Research Register, CBM (1983 to December 2009) and CNKI (1994 to December 2009), and traced the literature of the reference. The included objects were the resident of the iodine deficiency area and the age, the race. The sex was not limited. The fortified salt and the iodized salt effects were compared and the research quality was evaluated. Meta-analyses were conducted by the RevMan5.0 software. Results Eight studies involving 1 503 people were included. The goiter prevalence of the fortified salt which combined iodine with iron was lower than that of iodised salt [MD=1.22, 95%CI (0.90, 1.54)]. So was the thyroid gland volume [OR=1.88, 95%CI(1.01, 3.47)]. But the fortified salt which combined iodine with VA did not show this. Conclusion The fortified salt and the iodized salt can obviously improve the iodine nutritional status of people. The fortified salt has enhanced the effect while the iodized salt prevents iodine deficiency disorders, but more high grade randomized controlled trials are needed to confirm this.