Pre-pregnancy iodized salt improved children's cognitive development in randomized trial in Ethiopia

Interventions to improve the nutritional status of children under 5 years in Ethiopia: a systematic review

OBJECTIVE

To conduct a systematic review of experimental or quasi-experimental studies that aimed to improve the nutritional status of children under 5 years of age in Ethiopia.

DESIGN

Embase, MEDLINE/PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsychINFO, and Academic Search Database were used to locate peer-reviewed studies, and Google Scholar and Open Dissertation were used to locate grey literatures. All searches were conducted between 2000 and November 2022.

SETTING

Ethiopia.

PARTICIPANTS

Pregnant women and mothers with children aged 0-59 months.

RESULTS

Ten cluster randomised controlled trials (RCT), six quasi-experimental studies and two individual RCT were included. Out of the identified eighteen studies, three studies targeted pregnant mothers. Our findings showed that almost two-thirds of published interventions had no impact on childhood stunting and wasting, and more than half had no impact on underweight. Some behaviour change communication (BCC) interventions, food vouchers, micronutrient supplementation and quality protein maize improved stunting. Similarly, BCC and fish oil supplementation showed promise in reducing wasting, while BCC and the provision of quality protein maize reduced underweight. Additionally, water, sanitation and hygiene (WaSH) interventions provided to pregnant mothers and children under 2 years of age were shown to significantly reduce childhood stunting.

CONCLUSION

Future childhood nutritional interventions in Ethiopia should consider adopting an integrated approach that combines the positive effects of interdependent systems such as BCC, food supplemental programmes (e.g. boosting protein and micronutrients), health interventions (e.g. strengthening maternal and childcare), WaSH and financial initiatives (e.g. monetary support and income schemes).

Mandatory Versus Voluntary Implementation of Salt Iodization Program for the Last Two Decades in Ethiopia: A Comparative Review of Existing Literatures

BACKGROUND

Ethiopian government was implementing mandatory salt iodization program for the last decade to eliminate iodine deficiency disorders, but several recent studies reported mixed findings.

OBJECTIVE

This review aimed to assess the difference in implementation of iodized salt program 10 years before and after mandatory salt iodization being implemented in Ethiopia since 2011.

METHODS

In Ethiopia, legislation that enforces salt producers to iodize all salts used for human consumption started in February 2011. All studies about iodine deficiency and iodized salt conducted in Ethiopia in the last 2 decades were searched. Searches were performed in PubMed database. Google Scholar, Iodine Global Network, and Ethiopian Public Health Institute websites were also searched.

RESULTS

A total of 235 titles and abstracts were identified. After scanning the abstracts and full papers, 43 articles were remained for final data synthesis. In this review, all studies conducted before 2011 reported a urinary iodine concentration (UIC) value of < 100 μg/L and 66.7% of them reported a goiter prevalence of > 30%. On the other hand, among studies conducted after 2011, 88.9% reported UIC value < 100 μg/L and 73.7% reported goiter prevalence of > 30%. Household availability of adequately iodized salt increased from nearly 20% in pre 2011 to more than 50% in post 2011 period.

CONCLUSION

Despite the efforts made by the Ethiopian government on mandatory salt iodization for the last decade, iodine deficiency is sustained in the country. Moreover, the goal of universal salt iodization program is offtrack and needs urgent revision.

REGISTRATION

Registered on PROSPERO register with reg. no CRD42021251124.

The prevalence of insufficient iodine intake in pregnancy in Africa: a systematic review and meta-analysis

BACKGROUND

Fortification of foodstuffs with iodine, mainly through iodization of salt, which commenced in several African countries after 1995 is the main method for mitigating iodine deficiency in Africa. We assessed the degree of iodine nutrition in pregnancy across Africa before and after the implementation of national iodine fortification programs (CRD42018099434).

METHODS

Electronic databases and gray literature were searched for baseline data before implementation of population-based iodine supplementation and for follow-up data up to September 2020. R-metamedian and metamean packages were used to pool country-specific median urinary iodine concentration (UIC) estimates and derived mean UIC from studies with similar features.

RESULTS

Of 54 African countries, 23 had data on iodine nutrition in pregnancy mostly from subnational samples. Data before 1995 showed that severe iodine deficiency was prevalent in pregnancy with a pooled pregnancy median UIC of 28.6 μg/L (95% CI 7.6-49.5). By 2005, five studies revealed a trend towards improvement in iodine nutrition state in pregnancy with a pooled pregnancy median UIC of 174.1 μg/L (95% CI 90.4-257.7). Between 2005 and 2020 increased numbers of national and subnational studies revealed that few African countries had sufficient, while most had mildly inadequate, and some severely inadequate iodine nutrition in pregnancy. The pooled pregnancy median UIC was 145 μg/L (95% CI 126-172).

CONCLUSION

Improvement in iodine nutrition status in pregnancy following the introduction of fortification of foodstuffs with iodine in Africa is sub-optimal, exposing a large proportion of pregnant women to the risk of iodine deficiency and associated disorders.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018099434.

TSH Mediated the Effect of Iodized Salt on Child Cognition in a Randomized Clinical Trial

Objectives:

This study examines the hormonal mediators of the effect of iodized salt in pregnancy on child cognition.

Methods:

Sixty districts across 6 zones in the Amhara region of Ethiopia were randomly allocated to a control or intervention arm of early market access to iodized salt. Twenty-two villages per arm were randomly selected for this sub-study. A total of 1220 pregnant women who conceived after the intervention began were enrolled and assessed for their iodine and iron status. Data were collected once on the household socio-demographic status and iodized salt use, and maternal urinary iodine during pregnancy. Then, infants’ diet, urinary iodine level, cognitive development (Bayley III), serum hormonal levels, iron status, and inflammation markers were measured between 2 and 13 months of age.

Results:

The median maternal urinary iodine concentration was adequate and significantly higher in the intervention mothers than that of the controls (163 vs 121 µg/L, P < .0001). Intervention children compared to the control children had lower thyroid-stimulating hormone (TSH) (mean: 2.4 ± 1.0 µIU/mL vs 2.7 ± 1.0 µIU/mL, effect size = 0.18, P < .01) and thyroglobulin (Tg) (41.6 ± 1.0 ng/mL vs 45.1 ± 1.0 ng/mL, effect size = 0.14, P < .05). There was an interaction between the intervention and iron stores such that cognition was higher with iron (effect size = 0.28, 100 vs 94 IQ points). TSH was a partial mediator (12%) of the effect of the intervention on child cognition (Sobel z-score = 2.1 ± 0.06, P < .05).

Conclusion:

TSH partially mediated the effect of the iodized salt intervention on child cognition.

Pre-pregnancy iodized salt improved children's cognitive development in randomized trial in Ethiopia

The overarching Ethiopia project examined the effects of early market introduction of iodized salt on the growth and mental development of young children. Sixty districts were randomly assigned to intervention (early market access to iodized salt) or control (later access through market forces), and one community per district was randomly chosen as the sampling unit. For this project, 22 of the districts were included. The participants were 1,220 pregnant women who conceived after the intervention began. When their children were 2 to 13 months old, field staff collected information on household sociodemographic status and iodized salt intake, child stimulation, maternal depression symptoms, children's diet, anthropometry, urinary iodine concentration (UIC), hemoglobin, and mental development scores (Bayley III scales). Fewer mothers prepartum (28% vs. 41%, p < .05) and their children (13% vs. 20%, p < .05) were iodine deficient (UIC <50 μg/L) in the intervention compared with the control group. The intervention children had higher cognitive scores (33.3 ± 0.3 vs. 32.6 ± 0.3; Δ = 0.6; 95% CI [0.0, 1.3]; d = 0.17; p = .01; 4 IQ points) than their controls. The other Bayley subscale scores did not differ from control children. The intervention group had a higher child stimulation (22.7 ± 0.2 vs. 22.1 ± 0.2; Δ = 0.5; 95% CI [0.02, 0.89]; d = 0.17; p = .01) but not growth indicators (weight‐for‐age z score, length‐for‐age z score, and weight‐for‐length z score: −1.1 ± 0.1 vs. −1.1 ± 0.1, −1.7 ± 0.1 vs. −1.7 ± 0.1; −0.2 ± 0.1 vs. −0.1 ± 0.1, respectively, all p > .05) compared with their controls. Iodized salt intake improved iodine status of both pregnant women and their children and also child cognitive development.