Eliminación y prevención de la deficiencia de yodo en mujeres gestantes de Perú / Elimination and prevention of iodine deficiency in pregnant women from Peru

RESUMEN La deficiencia de yodo (DI) causa daño a través de todos los ciclos de la vida, la vulnerabilidad es mayor durante la gestación y la infancia. La yodación universal de la sal (IUS) para consumo humano es la estrategia más costo-efectiva y sostenible para su control. Perú ha logrado la eliminación sostenida de los desórdenes por deficiencia de yodo (DDI) desde 1994. Objetivo: Determinar la efectividad del programa nacional de control de los DDI y la estrategia IUS para satisfacer el mayor requerimiento de yodo y asegurar la nutrición óptima de yodo de las mujeres embarazadas de la sierra, una región con severa deficiencia natural de yodo. Material y Métodos: El estudio ha incluido a 489 mujeres embarazadas de la sierra, seleccionadas entre las asistentes a control pre natal en los centros asistenciales. En cada sujeto se verificó el consumo de sal yodada y se colectó una muestra casual de orina para el análisis de la concentración de yodo y creatinina. Resultados: Según la encuesta de admisión el 99.6 % de los hogares consumen sal yodada. La mediana global de la concentración urinaria de yodo (CUI) 209 µg/L está dentro del rango adecuado para gestantes y demuestra un estado nutricional de yodo normal. La concentración de creatinina en la orina es normal. Conclusión: Estos resultados confirman la eficiencia y el éxito del programa nacional para la eliminación sostenida de los DDI, garantizando la nutrición normal de yodo durante la gestación y, por lo tanto, previniendo el riesgo de daño cerebral de los recién nacidos cada año en la sierra.

ABSTRACT Iodine is an essential element for synthesizing thyroid hormones, it is also essential for cell metabolism and tissue development, especially in the brain. Iodine requirements are higher during pregnancy and lactation. Iodine deficiency (ID) is a widespread condition all over the world; it is frequent in Peruvian highlands and rainforest. ID causes damage in all life periods, and vulnerability for this is greater during pregnancy and infancy. Universal salt iodination (USI) for human use is the most cost-effective and sustainable strategy for controlling ID. Peru has achieved the sustained elimination of iodine deficiency disorders (IDD) since 1994. Objective. To determine the effectiveness of the national program for controlling IDDs and the USI strategy for complying with the increased iodine requirement and to assure optimal iodine nutrition in pregnant women from the Peruvian highlands, a region with severe natural iodine deficiency. Material and Methods. The study included 489 pregnant women from the highlands, who were selected from those attending prenatal assessment in healthcare centers. Iodinated salty consumption was verified in each subject and a casual urine sample was collected for measuring iodine and creatinine concentration. Results. According to the admission survey, 99.6% of household use iodinated salt. The overall mean of iodine urine concentration (IUC) was 209 µg/L, which is well within the adequate range for pregnant women, and it shows a normal iodine nutrition status. The creatinine urinary concentration was normal. Conclusion. These results confirm the efficiency and success of the national program for the sustained elimination of IDDs, assuring normal iodine nutritional supply during pregnancy; and, therefore, preventing the risk for brain damage in newborns every year in the highlands.

In Overweight Women, Adiposity-related Inflammation and Serum Hepcidin are Increased, Dietary Iron Bioavailability is decreased and Ascorbic Acid has Only a Negligible Enhancing Effect on Iron Bioavailability.

Objectives: Many countries are struggling with the double burden of malnutrition. Iron deficiency is prevalent in overweight and obese (OW/OB) subjects, likely due to adiposity-related inflammation increased hepcidin and decreased iron absorption. Because hepcidin reduces iron efflux from the basolateral enterocyte, whether luminal enhancers of iron absorption, like ascorbic acid (AA), would be effective in OW/OB subjects is uncertain. We compared iron bioavailability (FeB) from non-inhibitory meals with and without AA in normal weight (NW), OW, and OB women. Methods: In a randomized crossover study in young women (NW=25, OW=20 and OB=19), FeB from a test meal without (A) and with (B) AA was measured by using erythrocyte incorporation of Fe isotopic labels at 14d. Results: Inflammation and serum hepcidin were lower in the NW versus OW and OB. FeB from meal A was 20% in NW versus 12% in OW and 12% in OB (NW vs OW/OB: P=0.049). FeB from meal B was 28% in NW versus 15% in OW and 16% in OB (NW vs OW/OB: P=0.004). The %increase in FeB comparing A to B was greater in the NW (P<0.001) than in OW (P=0.178) or OB (P=0.008). Higher hepcidin predicted lower FeB (A:β=-0.458, P<0.001) Conclusions: Serum hepcidin is higher and FeB is lower in OW/OB compared to NW subjects. Moreover, the enhancing effect of AA on FeB in OW/OB subjects is blunted, consistent with the hypothesis that increased hepcidin in OW/OB limits iron absorption. The widespread increase in obesity may limit current dietary strategies to improve FeB in anemic women.

Strategies to Enhance Iron Absorption from Tef-injera in Young Women.

Objectives: Tef is a cereal indigenous to Ethiopia. The flour obtained is mostly used to produce a soft, pancake-like sourdough-bread, called injera. Since it contains considerable amounts of phytate, iron bioavailability from this Ethiopian staple is believed to be limited. We investigated different strategies to improve iron absorption from tef-injera. These included decreasing the phytate:iron molar ratio by simultaneously enhancing the iron content and lowering the phytate content during fermentation, by the addition of the enzyme phytase and by partially replacing tef by flours exhibiting high phytase activity. Additionally the impact of substituting FeSO4 by the alternative fortificant NaFeEDTA on bioavailability in humans was tested. Methods: Iron absorption was measured with stable isotopes in 2 groups of 17 young women in single-meal studies, serving modified tef-injera meals with tomato sauce in a cross-over design. Results: Iron absorption from traditional tef-injera was low (1.4%) and did not substantially increase with NaFeEDTA but approximately doubled (p<0.01) to 3.6% and 3.1% by reducing the phytate:iron molar ratio from 4.4 to 1.5 and 0.2 in variations with 10% wheat and purified phytase, respectively. Conclusions: Iron absorption was generally low from all meals and fortification of tef-injera with NaFeEDTA did not increase iron bioavailability compared to FeSO4, suggesting other factors, such as proteins or polyphenols, having an additional negative influence. Nevertheless, reducing the phytate content of tef-injera by either co-fortification with wheat or addition of purified phytase more than doubled iron bioavailability from this Ethiopian staple food and would provide additional absorbable iron.

Serum and Dried Blood Spot Thyroglobulin as a Functional Biomarker of Iodine Status during Pregnancy.

Objectives: Thyroglobulin (Tg) is a sensitive marker for iodine deficiency and excess in schoolaged children. DBS-Tg may be a promising functional biomarker also during pregnancy. Our objectives were to develop a new Tg assay and to determine if trimester-specific reference ranges are needed. Methods: A new Tg-ELISA for serum and DBS was developed, tested, and validated against Immulite, a conventionally serum Tg assay. Subjects were healthy women in 1st, 2nd and 3rd trimester of pregnancy. Serum or DBS-Tg concentrations were compared from iodine sufficient women in India (n=160) and Switzerland (n=590) to mildy iodine-deficient women in Thailand (n=260). Results: Median (IQR) serum Tg (μg/L) in mildly iodine-deficient Thai pregnant women with a median baseline UIC (IQR) of 110 (69-172) μg/L were: 9.6 (6.4-17.0), 10.4 (5.6-15.9), 11.9 (6.4- 22.3) in the 1st, 2nd and 3rd trimesters, respectively. Median (IQR) serum Tg (μg/L) in iodine sufficient Indian pregnant women with a median baseline UIC (IQR) of 184 (97-349) μg/L were: 7.1 (2.9-12.4), 7.2 (3.7-11.5), 7.0 (4.0-11.4) in the 1st, 2nd and 3rd trimesters, respectively. Median (IQR) DBS-Tg (μg/L) in iodine sufficient Swiss pregnant women with a median baseline UIC (IQR) of 162 (83-284) μg/L were: 7.9 (3.4-12.8) and 9.0 (4.3-15.8) in the 2nd and 3rd trimesters, respectively. Conclusions: Serum Tg concentrations may be higher in mildly iodine-deficient women compared to iodine sufficient women, and in iodine sufficient women, DBS-Tg concentrations may be higher than serum Tg concentrations. These data will contribute to the development of reference ranges for Tg concentrations to define iodine sufficiency in pregnant women.

Reducing Lead Burden and Improving Iron Status with Iron Fortification Using NaFeEDTA: A Double- Blind, Randomized, Placebo- Controlled Intervention Trial (RCT) in Lead-exposed Moroccan Children.

Objectives: Lead absorption from oral exposures may be increased in children with iron deficiency anemia (IDA). Therefore, iron fortification could be an effective adjunctive strategy to reduce lead burden in many urban areas in low-income and rapidly-developing countries. We investigated the effect of iron fortification with and without NaEDTA (a lead chelator) in Moroccan children; primary outcomes were serum ferritin and blood lead levels (BLL). Methods: Using a 2-by-2 factorial design, an RCT was done in children (n=453) receiving wheatbased biscuits containing either 1) 10 mg of FeSO4, 2) 10 mg of Fe as NaFe(III)EDTA, 3) NaEDTA alone or 4) control for 28 weeks. Biomarkers of iron status and lead burdenwere assessed by using a sparse serial sampling design. Cognition was assessed using the Kaufman Assessment Battery. Results: Iron status improved significantly in both iron groups: mean serum ferritin increased by 15.3 μg/L, 14.9μg/L and 4 μg/L in the FeSO4, NaFe(III)EDTA and EDTA groups respectively, compared to control (p<0.0001). IDA was significantly reduced in both iron groups (p<0.001). Mean BLL were reduced by 4.2 ng/g and 8.1 ng/g in the FeSO4 and NaFe(III)EDTA, compared to the control group. Conclusions: Both fortificants improved iron status similarly, and both reduced blood lead levels compared to control, but the reduction in BLL was two-fold greater with NaFe(III)EDTA. This is the first RCT to clearly demonstrate a reduction of BLL after iron fortification, and suggests additional benefit from supplying the iron as NaFe(III)EDTA. Analysis of the sparse serial sampling data will provide the kinetics of this effect.

Assessment of zinc Fortification of a Household- Based Water Filtration Device: Zn Absorption Using Stable Isotopes and Efficacy in a Controlled Trial in Beninese School Children.

Objectives: Zinc bioavailability from foods is limited due to the presence of absorption inhibitors. Water as a vehicle for zinc could be effective in improving zinc status. LifeStraw®Family (LSF) is a water filtration device that fortifies water with zinc. We assessed the absorption of zinc and the response of plasma zinc (PZn) to long-term consumption of the zinc fortified water. Methods: The LSF filters were placed in rural households in Benin (n=139) to assess compliance and acceptability. Bioavailability was measured in young adults with the urinary monitoring of two stable zinc isotopes. A double blind, randomised, controlled trial (RCT) was carried out in school children aged 5-10y (n=278) from a rural village in Benin. Over 20 weeks, including sparse midpoint sampling, children received either zinc fortified LSF-filtered water (Zn), non-fortified LSFfiltered water (Fltr) or non-fortified non-filtered water (Ctrl). The Zn group received a daily zinc dose of 4.6±2.2 mg. Results: Geometric mean (-SD,+SD) zinc absorption from fortified water was 65.9% (42.2,102.4). At baseline, mean PZn was 69.2±12.6 μg/dl and 35.9% of children were zinc deficient. During the RCT, there was a significant treatment effect on PZn (ANCOVA, p=0.029): final PZn in the Zn group was 4.2 and 1.9 μg/dl higher than the Fltr and the Ctrl group, respectively. Further analysis integrating the sparse midpoint PZn response will allow evaluation of plasma zinc kinetics. Conclusions: The LSF filter delivers water fortified with low doses of highly bioavailable zinc. Long-term consumption of zinc fortified water from the LSF filter improved zinc status in Beninese school children.

Evaluation of Zinc Bioavailability in Humans from Foliar Zinc Biofortified Wheat and from Intrinsic vs. Extrinsic Zn Labels in Biofortified Wheat.

Objectives: Zinc biofortification may be a sustainable way to improve Zn status, but questions remain on Zn bioavailability. We produced a novel biofortified wheat by Zn foliar application, and a separate wheat cultivar was intrinsically labeled with a Zn stable isotope. Goals were: a) To compare fractional and total Zn absorption (FAZ-TAZ) from chapattis prepared with biofortified, regular and postharvest fortified wheat; b) Compare the absorption of intrinsically and extrinsically Zn labels from biofortified wheat. Methods: Chapattis were prepared from flours with 100% and 80% extraction rates (ER). Meals were administered to 2 women's groups (N=44) in randomized order. Bioavailability was measured with double isotopic urinary technique with stable isotopes; four-day urines were collected and isotopic enrichment measured. Results: Foliar Zn application resulted in an increase of 45.6% of grain Zn. The control and biofortified wheat contained 25±0.12 ppm and 46±1.37 ppm Zn and 0.830±0.04 g/100 g and 0.807 ±0.03 g/100 g PA. The Zn:PA molar ratio for the unfortified, fortified and biofortified meals were 36, 63, 63 (100% ER) and 40, 67, 67 (80% ER). Mean total Zn in the intrinsically labeled wheat was 19.9±1.6 ppm. FAZ-TAZ data from the absorption studies are being analyzed. Conclusions: Foliar application increased Zn concentration without significantly changing PA concentration, and extraction rate is a determinant of the Zn:PA ratio. Assessment of FAZ-TAZ will provide: a) Data on the potential of foliar zinc biofortified wheat, and b) proof that the double isotope technique used to assess absorption of extrinsic Zn labels in biofortified wheat is valid.

Effect of Provitamin A-biofortified Cassava on Vitamin A Status of Kenyan Children: A Randomised Controlled Trial.

Objectives: To measure the effect of daily consumption of provitamin A-biofortified cassava on vitamin A status in children aged 5-13 years. Methods: Mild-to-moderate vitamin A deficient children (n=342) were randomly allocated to groups receiving: 1) 375 g of white cassava and placebo supplement; 2) 375 g of white cassava and a supplement of β-carotene (1,054 μg); 3) 375 g of biofortified cassava and placebo supplement. Children received the intervention 6 days/week for 18.5 weeks. Field staff and participants were blinded to supplementation. Cooked cassava was mashed with salt and 4 g of oil per portion. Biofortified cassava supplied 208 μg RAE, which is ~50% of the age-specific estimated average requirement for vitamin A for children. The primary endpoint was serum retinol concentration and secondary endpoint was serum β-carotene concentration, both at end of intervention; in the analysis, we adjusted for sex and serum concentrations at baseline of retinol, C-reactive protein and α1-acid-glycoprotein. Results: Complete data were collected for 337 children. Compliance to cassava feeding was similar between treatment groups. Preliminary results showed that consumption of biofortified cassava and β-carotene supplementation resulted in a similar increase in retinol concentrations (for both interventions, mean: 0.81 μmol/L versus 0.77 μmol/L; difference, 95% CI: 0.04 μmol/L, 0.00─0.07 μmol/L) but in a different increase in serum β-carotene concentration (for β-carotene supplement group, mean: 0.25 μmol/L (95% CI: 0.17─0.33), for biofortified cassava group, mean: 0.81 μmol/L (95% CI: 0.73-0.88)) Conclusions: Provitamin A-biofortified cassava improves the vitamin A status of primary school children in Kenya.

Using Stable Iron Isotopic Techniques and Serum Hepcidin Profiles to Optimize Iron Supplementation for Correction of Iron Deficiency in Young Women.

Objectives: Determine the duration and magnitude of the serum hepcidin (sHep) rise induced by oral iron (Fe) supplements from single and consecutive-day Fe doses and measure bioavailability in healthy subjects. Methods: Twenty six subjects (serum ferritin, SF <20 μg/L) were randomized in four groups and sHep, iron status and inflammation markers were monitored for 96 h. On day 1, no supplements were administered (control day). On days 2 and 3, subjects received iron supplements containing 40, 80, 160 and 240 mg Fe as FeSO4 in either single dose (SFe) or as two consecutive day doses (CDFe) labeled with stable iron isotopes 54FeSO4, 57FeSO4, 58FeSO4. Iron bioavailability was measured by assessing the isotopic enrichment of erythrocytic iron 14 days after stable isotope administration. Results: There was a significant effect of time of day (P<0.05) and iron dose on sHep (P<0.05). Compared to control days, sHep was significantly higher at 8h and 24h after administration for 80, 160 and 240 mg doses (P<0.05) but not for 40 mg. Iron absorption from the second CDFe dose compared to SD was not significantly decreased for 40 mg, but was decreased 37% for 80 mg, 31% for 160 mg and 45% for 240 mg (for all, P<0.01). Fractional absorption was highest from the 40 mg dose. Conclusions: In Fe-depleted women, CDFe at 80 mg or above increase sHep and this decreases iron bioavailability, while a dose of 40 mg does not. These important new data will help design optimal dosing regimens for Fe supplements in women.

Refinements to Assessment of Iodine Nutrition.

Objectives: The main target groups of iodine programs are pregnant women (PW) and nonpregnant women of reproductive age (NPW), yet surveys frequently focus on school age children (SAC). It is unclear whether median urinary iodine concentration (mUIC) in SAC can be used as a surrogate for PW and NPW. It is also unclear what range of iodine intake is adequate in SAC. The objectives of this research were to: 1) Compare mUIC values in SAC with those in PW and NPW; and 2) determine if the current mUIC range for SAC is appropriate by assessing thyroglobulin (Tg), a functional biomarker of iodine status. Methods: 1) The Iodine Task Force (ITF) reviewed surveys where mUIC in SAC, PW, and NPW were available and compared iodine status across groups; and 2) for determining the adequate range of mUIC in SAC, the ITF analyzed and interpreted a multicenter study. Results: 1) When SAC had adequate or above adequate iodine status, PW were inadequate in 47% of the surveys. 2) In SAC, the two current WHO/UNICEF/ICCIDD mUIC categories for classification of iodine nutrition as "adequate" and "above adequate" could be combined into a single "adequate" range based on Tg results showing no negative effect on the thyroid at the current "above adequate" range. Conclusions: A number of refinements to the current global recommendations in assessing iodine status were identified, including the importance of including PW and/or NPW in population-based assessments, and reconsideration of current mUIC criteria for the classification of optimal iodine nutrition in SAC.

Maternal Thyroid Function and Birth Outcomes after Iodine Supplementation in Mild-to-moderately Iodine-deficient Pregnant Women in Thailand.

Objectives: To evaluate the effects of iodine supplementation in mild-to-moderately iodinedeficient pregnant Thai women on maternal thyroid function and birth outcomes. Methods: An RCT with 200 μg KI per day was conducted among 514 mild-to-moderately iodinedeficient pregnant Thai women. Blood samples were collected at baseline (<14 weeks of gestation), and follow up samples were collected in the 2nd, and 3rd trimester and at delivery in cord blood. Free T4 (fT4), thyroglobulin (TG) and thyroid-stimulating hormone (TSH) concentration were measured. Neonatal data was obtained from hospital records. Thyroid volume of the newborns was measured using ultrasonography. Data were analyzed per protocol by linear mixed models and linear regression models. Results: Cumulative loss to follow up was 20% in the 2nd trimester, 23% in the 3rd trimester, and 28% at delivery. Median maternal fT4, TG and TSH concentration did not differ significantly between treatment groups (p>0.05). Mean birth weight was 3150±410 g in the iodine group as compared to 3088±473 g in the placebo group (p>0.05); 4.8% of infants in the iodine group were low birth weight versus 7.9% in the placebo group. There were no significant differences in median fT4, TG and TSH concentration, and mean thyroid volume of the newborns between treatment groups (p>0.05). Conclusions: Maternal iodine supplementation normalized iodine status and resulted in lower maternal TSH concentrations during pregnancy. Further data analysis should reveal whether iodine supplementation has led to any improvement in child development in this population.

Effects of High and Low Dose Iron-Containing Micronutrient Powders for In-Home Fortification of Complementary Foods on the Gut Microbiome and Gut Inflammation in Kenyan Infants.

Objectives: Primary outcome was change in composition of gut microbiome, after 3 weeks and 4 months. Secondary outcomes were changes in faecal calprotectin, treated diarrhoea, anaemia, iron status and systemic inflammation. Methods: We performed two randomized controlled trials in 6-month-old Kenyan infants consuming home-fortified maize porridge daily for four months. 1) infants received an MNP containing 2.5 mg iron as NaFeEDTA (+2.5 mgFeMNP) or the identical MNP without iron (-2.5 mgFeMNP). 2) a different MNP containing 12.5 mg iron as ferrous fumarate (+12.5 mgFeMNP) or the identical MNP without iron (-12.5 mgFeMNP). Results: We enrolled 117 infants, and 101 infants completed the studies between March 2010 and September 2012. Baseline prevalence of anaemia and systemic inflammation were 67.3% and 29.7%, respectively. At baseline, 63% of the total microbial 16S rRNA could be assigned to Bifidobacteriaceae; using qPCR, Salmonella was detected in 22.8% of infants, B. cereus in 38.6%, S. aureus in 71.3%, C. difficile in 53.5%, and C. perfringens in 86.1%. Body iron stores increased in the +12.5 mgFeMNP (p=0.001), but not in the +2.5 mgFeMNP. Using pyrosequencing, +FeMNPs increased enterobacteria, especially Escherichia/Shigella (p=0.048), the enterobacteria/ bifidobacteria ratio (p=0.020), and Clostridium (p=0.03) compared to -FeMNPs; +FeMNPs also increased faecal calprotectin (p=0.002). Most of these effects were confirmed using qPCR, and many were statistically stronger in ±12.5 mgFeMNP study than in ±2.5 mgFeMNP study. During the trial, 27.3% of infants in the +12.5 mgFeMNP group required treatment for diarrhoea vs. 8.3% in the -12.5 mgFeMNP group (p=0.092). Conclusions: In rural Africa where infectious disease burden is high, provision of iron-containing MNPs to infants increases gut inflammation and modifies the gut microbiome toward a potentially more pathogenic profile.

Need for coordinated programs to improve global health by optimizing salt and iodine intake / Necesidad de programas coordinados para mejorar la salud a escala mundial mediante la optimización de la ingesta de sal y yodo

High dietary salt is a major cause of increased blood pressure, the leading risk for death worldwide. The World Health Organization (WHO) has recommended that salt intake be less than 5 g/day, a goal that only a small proportion of people achieve. Iodine deficiency can cause cognitive and motor impairment and, if severe, hypothyroidism with serious mental and growth retardation. More than 2 billion people worldwide are at risk of iodine deficiency. Preventing iodine deficiency by using salt fortified with iodine is a major global public health success. Programs to reduce dietary salt are technically compatible with programs to prevent iodine deficiency through salt fortification. However, for populations to fully benefit from optimum intake of salt and iodine, the programs must be integrated. This review summarizes the scientific basis for salt reduction and iodine fortification programs, the compatibility of the programs, and the steps that need to be taken by the WHO, national governments, and nongovernmental organizations to ensure that populations fully benefit from optimal intake of salt and iodine. Specifically, expert groups must be convened to help countries implement integrated programs and context-specific case studies of successfully integrated programs; lessons learned need to be compiled and disseminated. Integrated surveillance programs will be more efficient and will enhance current efforts to optimize intake of iodine and salt. For populations to fully benefit, governments need to place a high priority on integrating these two important public health programs.

El alto contenido de sal en la dieta es una causa principal de incremento de la presión arterial, el principal factor de riesgo de muerte a escala mundial. La Organización Mundial de la Salud (OMS) ha recomendado que el consumo de sal sea inferior a 5 g/d, una meta que solo logran una pequeña proporción de personas. La falta de yodo puede causar deficiencia cognoscitiva y motora y, si es grave, hipotiroidismo, con grave retraso mental y del crecimiento. Más de dos mil millones de personas en todo el mundo presentan riesgo de carencia de yodo. La prevención de la carencia de yodo mediante el empleo de sal yodada constituye una importante conquista de salud pública a escala mundial. Los programas cuyo objeto es reducir el contenido de sal en la dieta son técnicamente compatibles con los programas de prevención de la carencia de yodo mediante el enriquecimiento de la sal. Sin embargo, para que las poblaciones se puedan beneficiar plenamente de una ingesta óptima de sal y yodo, es preciso integrar ambos tipos de programa. Este estudio resume las bases científicas de los programas de reducción de sal y enriquecimiento con yodo, la compatibilidad de esos programas, y las medidas que deben adoptar la OMS, los gobiernos nacionales y las organizaciones no gubernamentales para garantizar que las poblaciones se beneficien plenamente de una ingesta óptima de sal y yodo. En concreto, es preciso reunir a grupos de expertos para ayudar a los países a aplicar programas integrados y llevar a cabo estudios de casos en contextos específicos de programas integrados eficaces; es preciso recopilar y difundir las enseñanzas extraídas. La integración de los programas de vigilancia los hará más eficaces y mejorará las iniciativas actuales para optimizar la ingesta de yodo y sal. Para que las poblaciones puedan beneficiarse plenamente, es preciso que los gobiernos asignen una alta prioridad a la integración de estos dos importantes tipos de programas de salud pública.