Coverage and cost of iodized oil capsule distribution in Tanzania

The Long-Run Economic Consequences of Iodine Supplementation

We present evidence on the impacts of a large-scale iodine supplementation program in Tanzania on individuals' long-term economic outcomes. Exploiting the timing and location of the intervention, we document that in utero exposure to the program increased completed years of education and income scores in adulthood. We find no increase in total employment, but a significant change in the occupational structure. Cohorts exposed to the program are less likely to work in agricultural self-employment and more likely to hold skilled jobs that typically demand higher levels of education. Together, these results demonstrate that iodine deficiency can have long-run implications for occupational choices and labor market incomes in low-income regions.

Endowments at Birth and Parents' Investments in Children

Do parents invest more in higher quality children, or do they compensate for lower quality by giving more to children with lower endowments? We answer this question in the context of a large-scale iodine supplementation programme in Tanzania. We find that children with higher programme exposure were more likely to receive necessary vaccines and were breastfed for longer. Siblings of treated children were also more likely to be immunised. Fertility behavior and investments at the time of birth were unaffected.

Micronutrient program costs: sources of variations and noncomparabilities

BACKGROUND

Micronutrient interventions are contributing to substantial reductions in global morbidity and mortality. As the diversity and coverage of these interventions expand, it is increasingly important to understand their distinct roles and contributions, and the resources they require. To date, comparing program resource use has been hampered by several noncomparabilities in cost studies relating to diverse intervention activities and service delivery pathways, along with differences in methodological approaches.

OBJECTIVE

To promote better understanding of the variations and noncomparabilities in costs and cost structures of micronutrient interventions.

METHODS

Cost studies on supplementation, fortification and biofortification programs from the published and gray literature were reviewed (n = 130).

RESULTS

Specific areas of noncomparability identified include intervention characteristics and country context, as well as differences in methodological considerations, including data sources and definition of cost centers. Moreover, analyses vary significantly in terms of types of costs included. Implications and practical recommendations for standardizing future costing studies are provided.

CONCLUSIONS

Methodological variations and non-comparabilities do much more than limit the ability to make direct comparisons of costing studies; they carry important implications for the adoption, design, and implementation of interventions in countries suffering from micronutrient deficiencies. This study synthesizes evidence on the level of support required (both financial and otherwise) for programs to achieve desirable levels of coverage and performance. Having comparable and accurate estimates of costs is a necessary first step in planning for and implementing interventions that are of adequate scale and adequately resourced.

The challenges of iodine supplementation: a public health programme perspective

An adequate iodine intake during pregnancy, lactation and early childhood is particularly critical for optimal brain development of the foetus and of children 7-24 months of age. While the primary strategy for sustainable elimination of iodine deficiency remains universal salt iodisation, the World Health Organization and the United Nations Children's Fund recommend a complementary strategy of iodine supplements as a temporary measure when salt iodisation could not be implemented. This article aims to review current evidence on efficacy and implications of implementing iodine supplementation as a public health measure to address iodine deficiency. Iodine supplementation seems unlikely to reach high coverage in a rapid, equitable and sustained way. Implementing the programme requires political commitment, effective and efficient supply, distribution and targeting, continuous education and communication and a robust monitoring system. Thus, universal salt iodisation should remain the primary strategy to eliminate iodine deficiency.

Tanzania national survey on iodine deficiency: impact after twelve years of salt iodation

BACKGROUND

In many low-income countries, children are at high risk of iodine deficiency disorders, including brain damage. In the early 1990s, Tanzania, a country that previously suffered from moderate to severe iodine deficiency, adopted universal salt iodation (USI) as an intervention strategy, but its impact remained unknown.

METHODS

We report on the first national survey in mainland Tanzania, conducted in 2004 to assess the extent to which iodated salt was used and its apparent impact on the total goitre prevalence (TGP) and urinary iodine concentrations (UIC) among the schoolchildren after USI was initiated. In 2004, a cross-sectional goitre survey was conducted; covering 140,758 schoolchildren aged 6 - 18 years were graded for goitre according to new WHO goitre classification system. Comparisons were made with district surveys conducted throughout most of the country during the 1980s and 90s. 131,941 salt samples from households were tested for iodine using rapid field test kits. UIC was determined spectrophotometrically using the ammonium persulfate digestion method in 4523 sub-sampled children.

RESULTS

83.6% (95% CI: 83.4 - 83.8) of salt samples tested positive for iodine. Whereas the TGP was about 25% on average in the earlier surveys, it was 6.9% (95%CI: 6.8-7.0) in 2004. The TGP for the younger children, 6-9 years old, was 4.2% (95%CI: 4.0-4.4), n = 41,965. In the 27 goitre-endemic districts, TGP decreased from 61% (1980s) to 12.3% (2004). The median UIC was 204 (95% CF: 192-215) microg/L. Only 25% of children had UIC <100 microg/L and 35% were > or = 300 microg/L, indicating low and excess iodine intake, respectively.

CONCLUSION

Our study demonstrates a marked improvement in iodine nutrition in Tanzania, twelve years after the initiation of salt iodation programme. The challenge in sustaining IDD elimination in Tanzania is now two-fold: to better reach the areas with low coverage of iodated salt, and to reduce iodine intake in areas where it is excessive. Particular attention is needed in improving quality control at production level and perhaps the national salt iodation regulations may need to be reviewed.

Remaining challenges in Tanzania's efforts to eliminate iodine deficiency

OBJECTIVE

To determine iodine levels in salt and iodine deficiency prevalence in school-aged children in 16 districts in Tanzania with previous severe iodine deficiency.

DESIGN

A cross-sectional study in schoolchildren. Systematic probability sampling was used to select schools and subjects for goitre assessment and urinary iodine determination.

SETTING

Sixteen districts randomly selected from the 27 categorised as severely iodine-deficient in Tanzania.

SUBJECTS

The study population was primary-school children aged 6-18 years who were examined for goitre prevalence and urinary iodine concentration (UIC). Salt samples from schoolchildren's homes and from shops were tested for iodine content.

RESULTS

The study revealed that 83.3% of households (n=21,160) in the surveyed districts used iodised salt. Also, 94% of sampled shops (n=397) sold iodised salt, with a median iodine level of 37.0 ppm (range 4.2-240 ppm). Median UIC in 2089 schoolchildren was 235.0 microg l(-1) and 9.3% had UIC values below 50 microg l(-1). The overall unweighted mean visible and total goitre prevalence was 6.7% and 24.3%, respectively (n=16,222). The age group 6-12 years had the lowest goitre prevalence (3.6% visible and 18.0% total goitre, n=7147). The total goitre prevalence had decreased significantly in all districts from an unweighted mean of 65.4% in the 1980s to 24.3% in 1999 (P<0.05). We believe this difference was also biologically significant. ConclusionThese findings indicate that iodine deficiency is largely eliminated in the 16 districts categorised as severely iodine-deficient in Tanzania, and that the iodine content of salt purchased from shops is highly variable.

Iodine deficiency persists in the Zanzibar Islands of Tanzania

BACKGROUND

Iodine is an essential micronutrient for normal human growth and development. It is estimated that more than 1.6 billion people live in iodine-deficient environments, yet there are still some countries and areas where the prevalence of iodine-deficiency disorders is unknown.

OBJECTIVE

To establish the prevalence of iodine-deficiency disorders in the Zanzibar Islands, a community assumed to have ready access to iodine-rich seafoods.

METHODS

In a cross-sectional study, 11,967 schoolchildren were palpated for goiter prevalence, a subsample was evaluated for urinary iodine concentration, and the availability of iodated salt was assessed at the household and retail levels.

RESULTS

The mean total goiter prevalence was 21.3% for Unguja and 32.0% for Pemba. The overall median urinary iodine concentration was 127.5 microg/L. For Unguja the median was 185.7 microg/L, a higher value than the median of 53.4 microg/L for Pemba (p < .01). The household availability of iodated salt was 63.5% in Unguja and 1.0% in Pemba. The community was not aware of the iodine-deficiency problem and had never heard of iodated salt.

CONCLUSIONS

The inadequate intake of iodine documented in the Zanzibar Islands belies the common assumption that an island population with access to seafood is not at risk for iodine-deficiency disorders. We urge health planners to implement mandatory salt iodation and education efforts to alleviate the situation.

Goitre and iodine deficiency in Afghanistan: a case-control study

I deficiency is the leading cause of preventable mental retardation. A number of surveys in Afghanistan show goitre prevalence rates more than 20 % amongst children and women. Access to iodised salt remains low, with disparate coverage by region, despite the recent implementation of a national salt iodisation programme. The objectives were to identify whether the presence of goitre is a satisfactory marker of I deficiency and to examine the relationship between goitre and thyroid function. A case-control study was carried out in children and women of childbearing age, stratified on the presence of goitre. Adequate levels of urinary I were observed in 6.8 % of all the subjects, and amongst the subjects without goitre, this figure was only 9 %. The presence of goitre was significantly associated with severe urinary I deficiency; however, the difference between the cases and controls was not as great as expected. An association between the presence of goitre and elevated thyroid-stimulating hormone (TSH) levels was observed, but 14 % of the children without palpable goitre also showed abnormal TSH levels.Given that the majority of subjects showed some degree of I deficiency and that children without goitre may have elevated TSH levels, the absence of goitre is an insufficient indicator to determine adequate I status. The risk of subsequent development of goitre, in the currently non-goitre population, is elevated. This suggests that short-term I supplementation should be considered independently of the presence of goitre or urinary I level, until the access to and consumption of iodised salt is generalised.

The challenges of community-directed treatment with ivermectin (CDTI) within the African Programme for Onchocerciasis Control (APOC)

The principal strategy adopted by the African Programme for Onchocerciasis Control (APOC), for the control of onchocerciasis in the 19 countries of Africa that now fall within the programme's remit, is that of community-directed treatment with ivermectin (CDTI). Halfway through its 12-year mandate, APOC has gathered enough information on the main challenges to guide its activities in Phase 2. An analysis of reports and other documents, emanating from consultants, scientists, monitors and national and project-level implementers, indicates that there are three broad categories of challenge: managerial; technical; and socio-political. Under these three categories, this review identifies the most pertinent concerns that APOC must address, during Phase 2, to enhance the prospects of establishing sustainable systems for ivermectin distribution. The major challenges include: (1) maintaining timely drug-collection mechanisms; (2) integrating CDTI with existing primary-healthcare services; (3) strengthening local health infrastructure; (4) achieving and maintaining an optimal treatment coverage; (5) establishing and up-scaling community self-monitoring; (6) designing and implementing operations research locally; (7) ensuring the adequacy of community-directed distributors; (8) increasing the involvement of local non-govemmental develop organizations in the programme; (9) achieving financial sustainability; (10) implementing equitable cost-recovery systems; and (11) engaging in effective advocacy. The implications of the challenges and suggestions about how they are being (or could be) addressed are also highlighted in this brief review, which should be of value to other programmes and agencies that may be contemplating the adoption of this unique strategy.

Physiology and pharmacology of iodized oil in goiter prophylaxis

Thyroid complications resulting from excess iodide such as thyrotoxicosis, thyroiditis, sialadenitis, or hypothyroidism are much rarer after iodine supplementation with Lipiodol than with KI. They do not militate against its widespread use in endemic goiter populations, especially in pregnant women. However, patients with multinodular goiter should not be treated or should be treated only under careful observation. When Lipiodol-induced thyrotoxicosis occurs it tends to be mild or even subclinical and self-limited. If treatment is required, potassium perchlorate with or without thionamides is recommended. Iodide goiter has not been seen after Lipiodol supplementation, nor has thyroiditis. Sialadenitis occurs rarely. Iodide derived from Lipiodol readily enters the fetus, possibly by active transport, and theoretically endangers the fetus because autoregulation of the fetal thyroid occurs late during gestation. Despite the difficulty in distinguishing iodide goiter from iodide deficiency goiter of the newborn, no cases of neonatal iodide goiter have been reported. Possible mechanisms of thyroid inhibition by excess iodide are briefly discussed. The use of locally produced iodized plant oils is recommended for financial reasons as well as for the benefits derived from local participation.

Classification of thyroid size by palpation and ultrasonography in field surveys

BACKGROUND

Goitre surveys are used to assess the degree of iodine deficiency in a population. The change of goitre classification made by WHO in 1994 implied that a smaller thyroid size should be regarded as goitre. Furthermore, the acceptable goitre prevalence was lowered from 10% to 5%, and ultrasonography was recommended as a more precise method for diagnosis of goitre. We studied the effects of the change of palpation system, and compared the precision of the old and new systems with that of ultrasonographic examination.

METHODS

We studied 225 schoolchildren (aged 7-14 years) in a highland village in Tanzania. The size of the thyroid was assessed in duplicate by ultrasonography and by WHO's 1960 and 1994 palpation systems. The latter were done by three examiners. Variations within and between examination methods and examiners were assessed, and measurement errors by ultrasonography were assessed from duplicate examinations. The sensitivity and specificity of the two palpation systems were calculated, with diagnosis by ultrasonography as the gold standard. Apparent palpation prevalences were calculated at a "true" 5% prevalence.

FINDINGS

The lowered criterion for goitre resulted in an extra 20-33% of children being diagnosed as having goitre by palpation. The variation between repeat examinations was only slightly smaller by ultrasonography (kappa=0.63) than by experienced examiners (kappa=0.57-0.58). The variation between thyroid volume estimation by ultrasonography and the true volume was about 50% due to both measurement error and variation in the shape of thyroid lobes. The new goitre criterion decreased specificity from 76% to 29%, whereas sensitivity rose from 56% to 80%. In contrast, a suggested sharpening of the old criterion increased specificity to 90%.

INTERPRETATION

A return to the old (1960) palpation criterion for goitre: "lobes larger than the terminal phalanxes of thumbs" and to an accepted palpation goitre prevalence of 10% can allow affordable monitoring of thyroid size through palpation in field surveys.