Infant iron status affects iron absorption in Peruvian breastfed infants at 2 and 5 mo of age

Exploring the association between haematological markers of iron and general movements in 4-month-old infants exposed to anaemia in-utero

BACKGROUND

Iron is a vital micronutrient for brain development, influencing myelination, neurotransmitter balance, and the maturation of specific brain cells. Hence iron insufficiency in the foetal, neonatal and infancy period has the potential to influence the neuromotor development.

AIMS

We aimed to describe haematological markers of iron at 4 months of age in infants exposed to prenatal anaemia and explore the association with their quality of general movements.

STUDY DESIGN

Cross sectional study nested within the RAPIDIRON-KIDS trial.

SUBJECTS

All infants whose mothers were part of RAPIDIRON-KIDS trial, were eligible to participate in this study when the infants were 4 months old. Children suffering from fever or acute illness on the day of assessment, or with a history of either surgery, or admission to hospital in the first month were excluded.

OUTCOME MEASURES

Haematological markers of iron (Haemoglobin and Ferritin level) and quality of general movements in infants at 4 months of age.

RESULTS

120 infants were assessed with mean birth weight of 2685.5 g (±384.5) and median gestational age of 39 weeks [Q1, Q3:38,40]. There was no significant association between haemoglobin or ferritin levels with fidgety movements (p = 0.18 and p = 0.27, respectively). The combined effect of haemoglobin and ferritin estimates also did not show any significant association with the study groups (p = 0.21).

CONCLUSION

A majority of infants still had low iron indices at 4 months of age and this was not associated with the quality of general movements. A prospective longitudinal study needs to be considered in infants exposed to prenatal anaemia rather than assessing the outcomes at a single time point.

Measurement of iron absorption and iron gains from birth to 6 months in breastfed and formula-fed infants using iron isotope dilution

Little is known about iron kinetics in early infancy. We administered stable iron isotopes to pregnant women and used maternal-fetal iron transfer to enrich newborn body iron. Dilution of enriched body iron by dietary iron with natural isotopic composition was used to assess iron kinetics from birth to 6 months. In breastfed (BF, n = 8), formula-fed (FF, n = 7), or mixed feeding (MF, n = 8) infants, median (interquartile range) iron intake was 0.27, 11.19 (10.46-15.55), and 4.13 (2.33-6.95) mg/day; iron absorbed was 0.128 (0.095-0.180), 0.457 (0.374-0.617), and 0.391 (0.283-0.473) mg/day (BF versus FF, P < 0.01); and total iron gains were 0.027 (-0.002-0.055), 0.349 (0.260-0.498), and 0.276 (0.175-0.368) mg/day (BF versus FF, P < 0.001; BF versus MF, P < 0.05). Isotope dilution can quantify long-term iron absorption and describe the trajectory of iron depletion during early infancy.

Associations of maternal serum concentration of iron-related indicators with birth outcomes in Chinese: a pilot prospective cohort study

BACKGROUND

Previous studies of maternal iron and birth outcomes have been limited to single indicators that do not reflect the comprehensive relationship with birth outcomes. We aimed to investigate the relationship between maternal iron metabolism and neonatal anthropometric indicators using comprehensive iron-related indicators.

METHODS

A total of 914 Chinese mother-child dyads were enrolled in this prospective study. Subjects' blood samples were collected at ≤ 14 weeks of gestation. Serum concentrations of iron-related indicators were measured by enzyme-linked immunosorbent assay (ELISA). Femur length was measured by B-ultrasound nearest delivery. Neonatal anthropometric indicators were collected from medical records.

RESULTS

After adjustment for potential covariates, higher iron (per one standard deviation, SD increase) was detrimentally associated with - 0.22 mm lower femur length, whereas higher transferrin (per one SD increase) was associated with 0.20 mm higher femur length. Compared with normal subjects (10th-90th percentiles), subjects with extremely high (> 90th percentile) iron concentration were detrimentally associated with lower femur length, birth weight, and chest circumference, and a higher risk of low birth weight, LBW (HR: 3.92, 95%CI: 1.28, 12.0). Subjects with high concentration of soluble transferrin receptor, sTFR and transferrin (> 90th percentile) were associated with higher femur length. Subjects with low concentration of iron and ferritin concentrations (< 10th percentile) were associated with a higher risk of LBW (HR: 4.10, 95%CI: 1.17, 14.3) and macrosomia (HR: 2.79, 95%CI: 1.06, 7.35), respectively.

CONCLUSIONS

Maternal iron overload in early pregnancy may be detrimentally associated with neonatal anthropometric indicators and adverse birth outcomes.

Iron deficiency in healthy, term infants aged five months, in a pediatric outpatient clinic: a prospective study

BACKGROUND

Iron deficiency (ID) is prevalent in Malaysian children. The incidence of ID in infants under 6 months of age is unknown. Our aim was to determine the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) in healthy, term infants aged below 6 months in our hospital population.

METHODS

A prospective longitudinal pilot study of mother-infant pairs was conducted on infants receiving routine immunizations in a mother and child clinic at a university hospital, in Kuala Lumpur, Malaysia. Mothers completed standardized questionnaires at 3- and 5-month postnatal visits. Maternal and infant full blood count, ferritin, and C-reactive protein (CRP) levels were measured at 3 months and for the infants repeated at 5 months. Infant anthropometric measurements were obtained at both visits. We conducted a univariate analysis to identify factors associated with ID and IDA.

RESULTS

Altogether, 91 mother-infant pairs were enrolled, with 88 completing the study. No infant had ID or IDA at 3 months; the lowest ferritin level was 16.6 µg/L. At 5 months, 5.9% (5/85) of infants had ID, and 2.4% (2/85) had IDA. Median (interquartile range) infant ferritin levels significantly declined from 113.4 (65.0-183.6) µg/L at 3 months to 50.9 (29.2-70.4) µg/L at 5 months, p < 0.001. Exclusive breastfeeding until 3 or 5 months was significantly associated with ID at 5 months (p = 0.020, and p = 0.008, respectively) on univariate analysis. The drop in ferritin between 3-5 months was significantly associated with weight and length gains between 0-3 months (p = 0.018, p = 0.009, respectively). Altogether, 14.3% of infants exclusively breastfed until 5 months developed ID. At 5 months, 3.4% of infants were underweight, 1.1% stunted, and 10.2% wasted.

CONCLUSIONS

In exclusively breastfed term infants, ID occurred by 5 months. Early introduction of iron-rich foods should be considered in exclusively breastfed babies. A high prevalence of wasting suggests a calorie deficit in this population and will lead to stunting if not addressed.

Prevalence of Anemia and Associated Factors among Infants under Six Months in Rural China

OBJECTIVE

To examine haemoglobin level and anaemia status among infants under six months of age in rural China.

DESIGN

A cross-sectional survey collected data among infants under six months and their primary caregivers in Sichuan, China. Anaemia was defined using both the WHO and China Pediatrics Association thresholds. Multivariable linear regression was used to identify relevant factors among two age groups (<4 months; 4-5 months).

SETTING

80 townships were selected in Sichuan, China from November to December 2019.

PARTICIPANTS

942 infants under six months, while haemoglobin level were tested for 577 infants.

RESULTS

The overall mean (±SD) haemoglobin level was 106.03 (± 12.04) g/L. About 62.6% (95%CI: 58.5, 66.6) of sample infants were anemic using the WHO threshold, and 20.5% (95%CI: 17.3, 24.1) were anemic using the China Pediatrics Association thresholds. Anaemia rates rose with increasing age in months. Multivariable linear regressions revealed that lower haemoglobin levels were significantly associated with lower birth weight (<4 months: b = 4.14, 95% CI: 0.19, 8.08; 4-5 months: b = 6.60, 95% CI: 2.94, 10.27) and delivery by cesarean section (<4 months: b = -4.64, 95%CI: -7.79, -1.49; 4-5 months: b = -4.58, 95%CI: -7.45, -1.71).

CONCLUSION

A large share of infants under six months in rural western China are anemic. Infants with low-birth-weight and cesarean-delivered should be prioritized for anaemia testing. Future studies should move the point of focus forward to at least 4 months of age and examine the link between cesarean-section and anaemia to promote health and development in infancy.

Blood's Concentration of Lead and Arsenic Associated with Anemia in Peruvian Children

This exploratory, descriptive cohort study (N = 60) determined lead (Pb) and arsenic (As) blood concentrations in Peruvian children and their association with hematological parameters of iron-deficient anemia (IDA) and anthropometric measurement. The mean age of children was 10.8 months (SD = 4.7) and ranged from 3 to 24 months old. Anemia (Hb levels below 10.5 g/dL) was found in 20% of this cohort. Additionally, microcytosis (MCV < 70 fL) was present in 54%, and hypochromia (MCH < 23 pg) in 42% of the group of children. Chi-square analysis showed that 88% of the children with anemia also had microcytosis and hypochromia (p < 0.001). Pb and As were detected in 100% of the infants' blood samples, and the concentrations were significantly higher in older infants than in younger ones. Pb and As were not associated with the sex, anthropomorphic parameters, or infant hemogram changes. Infants who received iron supplementation were 87% less likely to have low Hb compared with those who did not (OR = 0.13, 95% CI = 0.02–0.88, p=0.04). Herbal tea intake was significantly associated with microcytosis and hypochromia. Our finding uncovered that hematological parameters for anemia are modified in Peruvian children with high levels of microcytosis and hypochromia. Concentrations of Pb and As were above method detection limits in all Peruvian children, but these were not associated with IDA or anthropometric measurements. A large study, including other variables, would benefit from allowing a more complex model predicting anemia in Peruvian children.

The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis

Iron is indispensable for human life. However, it is also potentially toxic, since it catalyzes the formation of harmful oxidative radicals in unbound form and may facilitate pathogen growth. Therefore, iron homeostasis needs to be tightly regulated. Rapid growth and development require large amounts of iron, while (especially young) children are vulnerable to infections with iron-dependent pathogens due to an immature immune system. Moreover, unbalanced iron status early in life may have effects on the nervous system, immune system and gut microbiota that persist into adulthood. In this narrative review, we assess the critical roles of iron for growth and development and elaborate how the body adapts to physiologically high iron demands during the journey from fetus to adolescent. As a first step towards the development of clinical guidelines for the management of iron disorders in children, we summarize the unmet needs regarding the developmental aspects of iron homeostasis.

The Benefits and Risks of Iron Supplementation in Pregnancy and Childhood

Iron deficiency is the most common micronutrient deficiency in the world and disproportionately affects pregnant women and young children. Iron deficiency has negative effects on pregnancy outcomes in women and on immune function and neurodevelopment in children. Iron supplementation programs have been successful in reducing this health burden. However, iron supplementation of iron-sufficient individuals is likely not necessary and may carry health risks for iron-sufficient and potentially some iron-deficient populations. This review considers the physiology of iron as a nutrient and how this physiology informs decision-making about weighing the benefits and risks of iron supplementation in iron-deficient, iron-sufficient, and iron-overloaded pregnant women and children.

Iron Metabolism and Brain Development in Premature Infants

Iron is important for a remarkable array of essential functions during brain development, and it needs to be provided in adequate amounts, especially to preterm infants. In this review article, we provide an overview of iron metabolism and homeostasis at the cellular level, as well as its regulation at the mRNA translation level, and we emphasize the importance of iron for brain development in fetal and early life in preterm infants. We also review the risk factors for disrupted iron metabolism that lead to high risk of developing iron deficiency and subsequent adverse effects on neurodevelopment in preterm infants. At the other extreme, iron overload, which is usually caused by excess iron supplementation in iron-replete preterm infants, might negatively impact brain development or even induce brain injury. Maintaining the balance of iron during the fetal and neonatal periods is important, and thus iron status should be monitored routinely and evaluated thoroughly during the neonatal period or before discharge of preterm infants so that iron supplementation can be individualized.

Effect of infant feeding practices on iron status in a cohort study of Bolivian infants

BACKGROUND

Iron deficiency (ID) is the most common micronutrient deficiency worldwide, with potentially severe consequences on child neurodevelopment. Though exclusive breastfeeding (EBF) is recommended for 6 months, breast milk has low iron content. This study aimed to estimate the effect of the length of EBF on iron status at 6 - 8 months of age among a cohort of Bolivian infants.

METHODS

Mother-infant pairs were recruited from 2 hospitals in El Alto, Bolivia, and followed from one through 6 - 8 months of age. Singleton infants > 34 weeks gestational age, iron-sufficient at baseline, and completing blood draws at 2 and 6 - 8 months of age were eligible for inclusion (N = 270). Ferritin was corrected for the effect of inflammation. ID was defined as inflammation-corrected ferritin < 12 μg/L, and anemia was defined as altitude-corrected hemoglobin < 11 g/dL; IDA was defined as ID plus anemia. The effect of length of EBF (infant received only breast milk with no other liquids or solids, categorized as < 4, 4 - 6, and > 6 months) was assessed for ID, IDA, and anemia (logistic regression) and ferritin (Fer) and hemoglobin (Hb, linear regression).

RESULTS

Low iron status was common among infants at 6 - 8 months: 56% of infants were ID, 76% were anemic, and 46% had IDA. EBF of 4 months and above was significantly associated with ID as compared with EBF <  4 months (4 - 6 months: OR 2.0 [1.1 - 3.4]; > 6 months: 3.3 [1.0 - 12.3]), but not with IDA (4 - 6 months: OR 1.4 [0.8 - 2.4]; > 6 months: 2.2 [0.7 - 7.4]), or anemia (4 - 6 months: OR 1.4 [0.7 - 2.5]; > 6 months: 1.5 [0.7 - 7.2]). Fer and Hb concentrations were significantly lower with increasing months of EBF.

CONCLUSIONS

Results suggest a relationship between prolonged EBF and ID, but are not sufficient to support changes to current breastfeeding recommendations. More research is needed in diverse populations, including exploration of early interventions to address infant IDA.

Are Infants Less than 6 Months of Age a Neglected Group for Anemia Prevention in Low-Income Countries?

Anemia is a major public health problem that affects mainly children, predominantly in low-income countries and most often due to iron deficiency (ID). Administration of iron supplements to prevent and treat ID anemia in malaria endemic areas has been controversial for decades; however, recent World Health Organization guidelines recommend universal iron supplementation for children in highly prevalent anemia settings, including those where malaria is endemic. However, infants younger than 6 months of age have been exempted from this recommendation because ID is not considered prevalent at this age and because of assumptions-without evidence-that they are protected from ID through breast milk. To achieve full impact of anemia prevention targeting infants less than 6 months of age who are at highest risk of ID, operational studies that conclusively demonstrate the effectiveness and safety of delivering iron supplements to young infants in settings with a high burden of infectious diseases, including malaria, are needed.

Iron Deficiency and Iron Deficiency Anemia in 3-5 months-old, Breastfed Healthy Infants

OBJECTIVE

To assess the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) in predominantly breastfed, 3-5-mo-old infants, born at term, with a birth weight ≥ 2.5 kg.

METHODS

The cross-sectional study was conducted in the outpatient department of a tertiary care center from January 2013 through December 2014.

INCLUSION CRITERIA

Age: 90-180 d, exclusively/predominantly breastfed, birth weight ≥ 2.5 kg and term gestation.

EXCLUSION CRITERIA

systemic illness, leucocytosis, leucopenia, thrombocytopenia, peripheral smear abnormality or iron supplementation. Blood sample was collected for complete blood count and ferritin assay. ID was defined as serum ferritin <12 μg/L. IDA was defined as ID plus Hb ≤ 10.5 g/dl.

RESULTS

Two hundred ninety six infants were initially recruited; 29 declined consent; 22 had leukocytosis, leucopenia or eosinophilia; 15 had thrombocytopenia; 15 samples were hemolyzed or insufficient. Finally, 215 infants were evaluated. The male-female ratio was 1.8:1. The mean birth weight was 2.9 (0.4) kg. The mean Hb was 10.8 (1.2) g/dl. The median serum ferritin was 44 μg/L (18, 120). The prevalence of ID at 3, 4 and 5 mo of age was 5.4%, 21.4% and 36.4%, while that of IDA was 4.6%, 16.7% and 11.4%, respectively.

CONCLUSIONS

The prevalence of ID at 4 and 5 mo of age in predominantly breastfed, term infants was 21.4% and 36.4%, respectively. The study generates evidence for considering iron supplementation for well-babies from 4 mo of age, instead of the currently recommended 6 mo by National Iron plus Initiative in India.

Multiple Biomarkers of Maternal Iron Predict Infant Cognitive Outcomes

This study examined relations between multiple measures of maternal iron status assessed 3 months post-partum, and infant processing speed (longest look during visual habituation), memory (novelty preference), attention (heart rate changes), and neural response variability (in auditory event-related potentials) at 3 and 9 months. Plasma iron was associated with 9-month novelty preference and longest look, and developmental changes in longest look. Hemoglobin predicted sustained attention, and both plasma iron and soluble transferrin receptors predicted neural response variability at 9 months. Improved maternal iron appears to have a positive impact on infant cognitive development even in a well-nourished, low-risk sample.

Early deterioration of iron status among a cohort of Bolivian infants

Iron deficiency (ID) and iron deficiency anemia (IDA) are major contributors to infant and maternal morbidity worldwide. There is limited longitudinal data on iron status in young infants and on methods to adjust iron biomarkers for inflammation. We aimed to quantify the prevalence of inflammation-adjusted ID, anemia, and IDA over the first year in a cohort of Bolivian infants and their mothers. Healthy mother-infant dyads were recruited from two peri-urban hospitals. Infants provided three blood draws (2, 6-8, and 12-18 months; N = 160); mothers provided two blood draws (1 and 6-8 months postpartum [plus third anemia measurement at 12-18 months]; N = 250). Blood was analyzed for hemoglobin, ferritin, soluble transferrin receptor, C-reactive protein (CRP), and alpha(1)-acid glycoprotein (AGP). Iron biomarkers were adjusted for inflammation using CRP and AGP; hemoglobin cutoffs were adjusted for altitude. Inflammation (elevated CRP or AGP) was 17% among toddlers 12-18 months of age. ID (inflammation-adjusted ferritin) increased with age (<1%, 56%, and 79% at each blood draw), as did anemia and IDA (anemia: 70%, 76%, and 81%; IDA: <1%, 46%, and 68%). Maternal ID declined from the first to second assessment (39% vs. 27%). Inflammation-adjusted ID prevalence was up to 15 percentage points higher than unadjusted estimates. The high prevalence of ID, anemia, and IDA in this cohort of Bolivian infants beginning at 6-8 months of age suggests that early interventions may be necessary in vulnerable populations.

Identification, prevention and treatment of iron deficiency during the first 1000 days

Iron deficiency is a global problem across the life course, but infants and their mothers are especially vulnerable to both the development and the consequences of iron deficiency. Maternal iron deficiency during pregnancy can predispose offspring to the development of iron deficiency during infancy, with potentially lifelong sequelae. This review explores iron status throughout these "first 1000 days" from pregnancy through two years of age, covering the role of iron and the epidemiology of iron deficiency, as well as its consequences, identification, interventions and remaining research gaps.