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Background: Despite the emergence of diverse programs in Mexico to address anemia and micronutrient deficiencies in disadvantaged groups, progress on reducing their prevalence has stagnated. In Mexico, anemia surveillance at the population level is conducted through the National Health and Nutrition Survey ENSANUT (for its acronym in Spanish). Objective: To overview the trends in anemia and iron deficiency (ID) from 1999 to 2018-19 in the Mexican population before COVID-19 pandemic. Methods: Data from five nationwide surveys in Mexico were used. Where available, data on anemia, ID, and ID anemia (IDA) were extracted from ENSANUTs 1999, 2006, 2012, 2016, and 2018-19 in participants from 1 to 99 years old. Blood sample collection methods were similar across surveys (1999-2018) where capillary drop blood was used to estimate Hb using a HemoCue and serum blood samples to measure ferritin and C-reactive protein concentration. Results: The trend in anemia prevalence shows a U-shape from 1999 to 2018-19 in <60 years old. In older adults (≥60 years), an increasing trend was observed. Anemia declined progressively from 1999 to 2012 but increased from 2016 to 2018-19 in comparison with 2012. In contrast, ID declined from 2006 to 2018-19, mainly in children, while IDA did not change over this period. In older adults, ID prevalence remained constant over time. Conclusions: The shifting trend in anemia prevalence across ENSANUTs 1999 through 2018-19 did not mimic the decreasing trend of ID over the same period of time. Other noncausal factors seem to play an important role in the variability of hemoglobin measurements. Plain language title: Overview of Trends in the Prevalence of Anemia and Iron Deficiency in the Mexican Population From 1999 to 2018-19 Plain language summary: In Mexico, anemia surveillance has been monitored through the National Health and Nutrition Survey since 1999. Nonetheless, progress on reducing their prevalence seems to be stagnated despite the emergence of diverse social programs in Mexico to tackle micronutrient deficiencies in children and women. The main cause of anemia in children and women is iron deficiency (ID). Any progress in tackling ID should be reflected in anemia prevalence. To investigate the prevalence trend, we used information about anemia (based on hemoglobin concentration) and ID (based on serum ferritin levels) where available, from 5 nationwide surveys in Mexico among participants from 1 to 99 years old, to discuss some of the potential factors behind anemia and ID trends. From 1999 to 2018-19, we observed an ¨U" shape in the prevalence of anemia in all age groups <60 years old, contrasting with the prevalence of ID, which trend is in decline. No major changes in terms of social programs can explain the trend in anemia. In fact, other nutritional indicators seem to have improved in Mexican children. A major difference in the measurement of anemia and ID is that hemoglobin was measured in situ using drop of capillary blood in HemoCue, a portable photometer, while ferritin was measured in venous blood in the central laboratory. While many external factors might influence the hemoglobin measurement in the field setting, it seems that the technique of finger prick capillary introduces more errors to the measurement of hemoglobin than other techniques (e.g., pool capillary or venous blood using HemoCue). This difference, in turn, affects anemia diagnosis. Since the drop of capillary blood has been widely acceptable, we did not perform any validation of hemoglobin measurement in those past surveys, so we cannot role out the contribution of other factors that affected hemoglobin measurement. Future studies should use venous blood to improve anemia classification; otherwise, validation studies should be carried out to improve hemoglobin measurement when using capillary blood. [ABSTRACT FROM AUTHOR]

Background. The associations among dietary zinc intakes and biomarkers of zinc status are unknown in apparently healthy children at high risk for zinc deficiency. Objective. To assess associations among zinc-related parameters in a sample of Guatemalan school-aged children. Methods. We assessed total dietary intakes and biomarkers of zinc status before and after receiving 6 months of zinc supplementation or placebo in 691 Guatemalan schoolchildren aged 6 to 11 years. Most of the children also received zinc-fortified milk from a government program that started shortly after the trial began. We assessed associations between zinc intakes and serum zinc, alkaline phosphatase (ALP), and albumin. Results. At baseline, the prevalence of serum zinc < 65 µg/dL and dietary zinc intake below Estimated Average Requirements (EAR) (< 4 and < 7 mg/day for children < 9 and ≥ 9 years, respectively) were 21.6% and 39.4%, respectively. Pearson correlations between serum zinc concentration and dietary zinc intake, serum ALP, and serum albumin were r = 0.07, 0.15, and 0.07, respectively. At the 6-month follow-up, low serum zinc and low total (diet plus fortified milk) zinc intakes were observed in 1.2% and 0.0% of children in the zincsupplemented group and 4.0% and 34.1% in the placebo group, respectively. Pearson correlations between serum zinc concentration and total zinc intake, serum ALP, and serum albumin were 0.10, 0.06, and -0.11 in the zinc-supplemented group and -0.04, 0.05, and 0.01 in the placebo group, respectively. Conclusions. Zinc intake was inconsistently associated with markers of serum zinc concentration. Zinc fortification or supplementation attenuated the associations. [ABSTRACT FROM AUTHOR]

The essentiality of folate and vitamin B12 for the synthesis of DNA may interfere with a successful pregnancy outcome when the mother is deficient in these micronutrients. The objective of this paper is to assess the effects of folate and vitamin B12 deficiencies on pregnancy outcomes, other than neural tube defects (NTD), and the effects of these deficiencies on infant and child development. Supplementation studies identified by two Cochran Reviews were selected to assess the impact of folate deficiency on pregnancy outcomes, and a systematic review of the literature was used to assess their effects on infant and child developments. Folate supplementation consistently resulted in improvement of hematological and folate status indicators. Seven supplemental studies consistently found no differences in the risk of total fetal loss, early or late miscarriage, stillbirth, preeclampsia, perinatal death, neonatal death, preterm birth, small-for-gestational age, or infant death in supplemented women compared with their controls. Two of those studies found greater placental weights (difference 96 g; 95% CI, 30.7 to 161.2 g), birthweights (difference 312 g; 95% CI, 108.5 to 515.4 g), and a lower risk for newborns weighing < 2,500 g in supplemented women (RR = 0.94; 95% CI, 0.90 to 0 .99). Abnormal vitamin B12 and homocysteine serum concentrations were more readily associated with poor pregnancy outcomes. The very few studies addressing the effects of folate and vitamin B12 deficiencies on infant and child development were inconclusive. Early supplementation with folate to pregnant women improves hematological and folate status indicators, but has little or no effect on pregnancy outcomes, other than on NTD. Vitamin B12 deficiencies and low homocysteine are more readily associated with poor pregnancy outcomes. [ABSTRACT FROM AUTHOR]