Iodine intervention, effects

Table 79.6 Effects of iodine intervention and measurement of economic benefits in a human popuiation...

Notes The important consequences of iodine deficiency in fhe affecfed human popuiafion are menfai deficiency, deaf mutism and hypothyroidism, which increase the economic cost of treatment and reduce the individuai/community work output/productivity. iodine intervention in such communities reduced such adverse heaith effects which, in turn, increased work output both at the individuai and at the community ievei, reduced the cost of medicai assessment and treatment, and reduced educationai costs. 

Notes The probabie costs of iodine deficiency in animai production can be estimated in terms of reduced miik and meat production, and reduced wooi production, as weii as reduction in the production of eggs and fish. Effects of iodine intervention on the economic benefits on the iivestock popuiation are very significant. 

In an intervention study with schoolchildren 8—10 years old in Malawi, Furnee et al. (1997) examined the relationship of intestinal parasite treatment and oral iodized oil efficacy. Severely iodine-deficient schoolchildren with a single parasitic infestation, either A. lumbricoides (n = 44), hookworm (n = 42), or Entamoeba histolytica (n = 24), were randomly allocated to receive or not receive treatment before taking a 1ml oral supplement (490 mg Iodine) of iodized ethyl esters from poppyseed oil. After supplementation, urinary iodine concentrations were measured regularly, to define time intervals indicating moderate iodine deficiency before urinary iodine concentrations returned to 0.40 mmol/1. Treatment with metronidazole for E. histolytica increased the protection period from 2.0 to 21.0 weeks P < 0.05). For all untreated children, the duration effect was 9.2 weeks shorter P < 0.001) than for their treated peers (16.8 weeks). They concluded that, by interfering with absorption, intestinal parasitic infestations reduce the efficacy of oral supplementation with iodized ethyl esters (Table 52.8). 

The two pre-intervention surveys were conducted to determine the status of urinary iodine levels in a representative sample of Tasmanian primary schoolchildren following more than a decade without regular monitoring. The four post-intervention surveys were conducted to examine the effects on urinary iodine levels following the voluntary fortification of bread with iodine. In addition to the assessment of urinary iodine levels, information on SES and geographical location was collected both pre- and post-intervention. Pre-intervention data on dietary sources of iodine were also collected. 

For the pre-intervention surveys logarithmic transformation of the UIC produced symmetric and approximately normal distributions and where possible analysis was performed using the transformed iodine concentration. For many of the results, however, medians and results of nonparametric tests are reported to enable comparison with the post-intervention surveys. In examining the differences between years some subjects had been sampled on both occasions. To remove the effect of the assumed correlation between subjects sampled on multiple occasions, a linear mixed model analysis including subjects as random effects was used to test the difference between log iodine in the pre-intervention years. 

The dietary associations were generally weak, but the true associations may have been masked by measurement error including that arising ffom intraindividual variation in spot measurements of urinary iodine. An individuals iodine concentration varies substantially day-to-day, due to the combined effects of circadian patterns of iodine excretion (Als et at, 2000), rapid renal clearance of dietary iodine following meals and inconsistency in the iodine content of food. We were able to average measures for children in the pre-intervention surveys who participated... 

Globally, almost two billion people (one-third of the human race) are affected by vitamin A, iron, iodine, and/or zinc deficiencies that put them at an increased risk of poor growth, morbidity, intellectual impairment, and/or mortality. Since the mid-1980s micronutrient supplementation has been a major public-health strategy in developing countries to prevent and control deficiencies in vitamin A, iron, and, to a lesser extent, iodine. More recently, zinc supplementation has come to be considered as an efficacious adjunctive therapy for diarrhea in populations with an elevated risk of zinc deficiency. This article will define micronutrient supplementation, examine the role of supplementation as a strategy for the prevention and control of micronutrient deficiencies, and examine evidence for vitamin A, iron, iodine, and zinc supplementation interventions with respect to efficacy, recommended dose, frequency of administration, safety, and program effectiveness. 

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