Relative Contributions of Malaria, Inflammation, and Deficiencies of Iron and Vitamin A to the Burden of Anemia during Low and High Malaria Seasons in Rural Zambian Children

Improving Anemia Assessment in Clinical and Public Health Settings

We aim to provide a practical approach to assess anemia and its primary causes, both in clinical settings and in the context of public health programs. Anemia remains a global challenge; thus, to achieve goals for anemia reduction and assess progress, standardized approaches are required for the assessment of anemia and its causes. We first provide a brief review of how to assess anemia, based on hemoglobin concentrations and cutoffs that correspond to age, sex, and physiologic status. Next, we discuss how to assess the likely causes of anemia in different settings. The causes of anemia are classified as non-nutritional (for example, because of infection, inflammation, blood loss, or genetic disorders) or nutrition-specific (for example, because of deficiencies of iron, vitamin A, riboflavin, vitamin B12, or folate). There is an important overlap between these 2 categories, such as the increased likelihood of iron deficiency in the context of inflammation. Given the multifaceted nature of anemia etiology, we introduce a framework for anemia assessment based on the "ecology of anemia," which recognizes its many overlapping causes. This conceptual framework is meant to inform what data on anemia causes may need to be collected in population surveys. The framework has a supporting table with information on the diagnostic tests, biomarkers and proposed cutoffs, characteristics, and feasibility of collecting the myriad information that can help elucidate the anemia etiology. We also provide examples of how this framework can be applied to interpret the anemia risk factor data from population-based surveys that can inform decisions about context-specific interventions. Finally, we present research gaps and priorities related to anemia assessment.

Oxidative Stress in Malaria: Potential Benefits of Antioxidant Therapy

Malaria is an infectious disease and a serious public health problem in the world, with 3.3 billion people in endemic areas in 100 countries and about 200 million new cases each year, resulting in almost 1 million deaths in 2018. Although studies look for strategies to eradicate malaria, it is necessary to know more about its pathophysiology to understand the underlying mechanisms involved, particularly the redox balance, to guarantee success in combating this disease. In this review, we addressed the involvement of oxidative stress in malaria and the potential benefits of antioxidant supplementation as an adjuvant antimalarial therapy.

Essential metals, vitamins and antioxidant enzyme activities in COVID-19 patients and their potential associations with the disease severity

The role of micronutrient deficiency in the pathogenesis of COVID-19 has been reviewed in the literature; however, the data are limited and conflicting. This study investigated the association between the status of essential metals, vitamins, and antioxidant enzyme activities in COVID-19 patients and disease severity. We recruited 155 patients, who were grouped into four classes based on the Adults guideline for the Management of Coronavirus Disease 2019 at King Faisal Specialist & Research Centre (KFSH&RC): asymptomatic (N = 16), mild (N = 49), moderate (N = 68), and severe (N = 22). We measured serum levels of copper (Cu), zinc (Zn), selenium (Se), vitamin D₃, vitamin A, vitamin E, total antioxidant capacity, and superoxide dismutase (SOD). Among the patients, 30%, 25%, 37%, and 68% were deficient in Se (< 70.08 µg/L), Zn (< 0.693 µg/mL), vitamin A (< 0.343 µg/mL), and vitamin D₃ (< 20.05 µg/L), respectively, and SOD activity was low. Among the patients, 28% had elevated Cu levels (> 1.401 µg/mL, KFSH&RC upper reference limit). Multiple regression analysis revealed an 18% decrease in Se levels in patients with severe symptoms, which increased to 30% after adjusting the model for inflammatory markers. Regardless of inflammation, Se was independently associated with COVID-19 severity. In contrast, a 50% increase in Cu levels was associated with disease severity only after adjusting for C-reactive protein, reflecting its possible inflammatory and pro-oxidant role in COVID-19 pathogenesis. We noted an imbalance in the ratio between Cu and Zn, with ~ 83% of patients having a Cu/Zn ratio > 1, which is an indicator of inflammation. Cu-to-Zn ratio increased to 45% in patients with mild symptoms and 34%–36% in patients with moderate symptoms compared to asymptomatic patients. These relationships were only obtained when one of the laboratory parameters (lymphocyte or monocyte) or inflammatory markers (neutrophil-to-lymphocyte ratio) was included in the regression model. These findings suggest that Cu/Zn might further exacerbate inflammation in COVID-19 patients and might be synergistically associated with disease severity. A 23% decrease in vitamin A was seen in patients with severe symptoms, which disappeared after adjusting for inflammatory markers. This finding may highlight the potential role of inflammation in mediating the relationship between COVID-19 severity and vitamin A levels. Despite our patients’ low status of Zn, vitamin D₃, and antioxidant enzyme (SOD), there is no evidence of their role in COVID-19 progression. Our findings reinforce that deficiency or excess of certain micronutrients plays a role in the pathogenesis of COVID-19. More studies are required to support our results.

Approaches to quantify the contribution of multiple anemia risk factors in children and women from cross-sectional national surveys

BACKGROUND

Attributable fractions (AF) of anemia are often used to understand the multifactorial etiologies of anemia, despite challenges interpreting them in cross-sectional studies. We aimed to compare different statistical approaches for estimating AF for anemia due to inflammation, malaria, and micronutrient deficiencies including iron, vitamin A, vitamin B12, and folate.

METHODS

AF were calculated using nationally representative survey data among preschool children (10 countries, total N = 7,973) and nonpregnant women of reproductive age (11 countries, total N = 15,141) from the Biomarkers Reflecting Inflammation and Nutrition Determinants of Anemia (BRINDA) project. We used the following strategies to calculate AF: 1) Levin's formula with prevalence ratio (PR) in place of relative risk (RR), 2) Levin's formula with odds ratio (OR) in place of RR, and 3) average (sequential) AF considering all possible removal sequences of risk factors. PR was obtained by 1) modified Poisson regression with robust variance estimation, 2) Kleinman-Norton's approach, and 3) estimation from OR using Zhang-Yu's approach. Survey weighted country-specific analysis was performed with and without adjustment for age, sex, socioeconomic status, and other risk factors.

RESULTS

About 20-70% of children and 20-50% of women suffered from anemia, depending on the survey. Using OR yielded the highest and potentially biased AF, in some cases double those using PR. Adjusted AF using different PR estimations (Poisson regression, Kleinman-Norton, Zhang-Yu) were nearly identical. Average AF estimates were similar to those using Levin's formula with PR. Estimated anemia AF for children and women were 2-36% and 3-46% for iron deficiency, <24% and <12% for inflammation, and 2-36% and 1-16% for malaria. Unadjusted AF substantially differed from adjusted AF in most countries.

CONCLUSION

AF of anemia can be estimated from survey data using Levin's formula or average AF. While different approaches exist to estimate adjusted PR, Poisson regression is likely the easiest to implement. AF are a useful metric to prioritize interventions to reduce anemia prevalence, and the similarity across methods provides researchers flexibility in selecting AF approaches.

Association of Iron-Deficiency Anemia and Non-Iron-Deficiency Anemia with Neurobehavioral Development in Children Aged 6-24 Months

(1) Background: Anemia has comprehensive adverse effects on the growth and development of children. In this study, we analyzed the potential effects of different types of anemia on early-life neurobehavioral development. (2) Methods: A total of 2601 children aged 6-24 months, whose parents agreed to participate in this study, underwent routine blood tests and neurobehavioral development assessment. The children's parents or other primary caregivers were interviewed with a face-to-face questionnaire at the time of enrollment in the study. Anemia was determined by hemoglobin < 110 g/L and classified into iron-deficiency and non-iron-deficiency anemia according to the levels of serum ferritin, C-reactive protein, and alpha-1-acid glycoprotein. Neurobehavioral development was assessed by the China Developmental Scale for Children and divided into five domains: gross motor, fine movement, adaptability, language, and social behavior. The development quotient (DQ) was used to measure the level of total neurobehavioral development and each domain of neurobehavioral development. (3) Results: The prevalence of anemia in children aged 6-24 months was 26.45%, of which iron-deficiency anemia only accounted for 27.33%. Compared with children without anemia, those with iron-deficiency anemia had a significantly lower developmental quotient (DQ) for total neurobehavioral development and gross motor and adaptability development. The partial regression coefficients were -1.33 (95% CI -2.36, -0.29; p = 0.012), -1.88 (95% CI -3.74, -0.03; p = 0.047), and 1.48 (95% CI -2.92, -0.05; p = 0.042), respectively. Children with non-iron-deficiency anemia had significantly lower DQ for total neurobehavioral development and gross motor and fine movement development than those without anemia. The partial regression coefficients were -0.94 (95% CI -1.64, -0.25; p = 0.008), -1.25 (95% CI -2.48, -0.03; p = 0.044), and -1.18 (95% CI -2.15, -0.21; p = 0.017), respectively. There were no statistically significant differences in total neurobehavioral development and the five domains of neurobehavioral development between children with non-iron-deficiency and iron-deficiency anemia. The partial β values were 0.40 (95% CI -1.53, 2.33; p = 0.684), 0.21 (95% CI -1.39, 1.81; p = 0.795), 0.63 (95% CI -1.03, 2.28; p = 0.457), 0.16 (95% CI -1.78, 2.10; p = 0.871), 0.35 (95% CI -1.32, 2.01; p = 0.684), and 0.34 (95% CI -0.77, 1.46; p = 0.545), respectively. (4) Conclusions: Both iron-deficiency anemia and non-iron-deficiency anemia were negatively correlated with the neurobehavioral development of children. Negative correlations were found between iron-deficiency anemia and gross motor and adaptability development and between non-iron-deficiency anemia and gross motor and fine movement development.

Age-specific differences in the magnitude of malaria-related anemia during low and high malaria seasons in rural Zambian children

BACKGROUND

Malaria causes anemia by destruction of red blood cells and inhibition of erythropoiesis.

OBJECTIVE

We assessed whether the magnitude of the malaria-specific effect on anemia differs by age, during low and high malaria seasons.

METHOD

In rural Zambian children participating in a pro-vitamin A efficacy trial, we estimated differences in the prevalence of anemia (defined as hemoglobin < 110 g/L for children < 60 months. and < 115 g/L in older children) by malaria status and assessed malaria-age interactions. Regression models (with anemia as the outcome) were used to model malaria-age interaction in both the low and high malaria seasons, controlling for potential confounders.

RESULTS

Average age was 68 months at baseline (n = 820 children). In the low malaria season, anemia prevalence was 29% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with no malaria-age interactions (p = 0.44). In the high malaria season, anemia prevalence was 41% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with significant malaria-age interactions (p = 0.02 for anemia). Age-stratified prevalence of anemia in malaria positive versus negative children was 67.0% versus 37.1% (in children < 60 months); 57.0% versus 37.2% (in 60-69 months.); 46.8% versus 37.2% (in 70-79 months.); 37.0% versus 37.3% (in 80-89 months) and 28.0% versus 37.4% (in 90+ months).

CONCLUSIONS

Malarial anemia is most severe in younger children, especially when transmission is intense. Anemia control programs must prioritize this vulnerable group.

Iron deficiency anaemia among 6-to-36-month children from northern Angola

BACKGROUND

Angola is one of the southern African countries with the highest prevalence of anaemia. Identifying anaemia determinants is an important step for the design of evidence-based control strategies. In this study, we aim at documenting the factors associated with Iron Deficiency Anaemia (IDA) in 948 children recruited at the Health Research Center of Angola study area during 2015.

METHODS

Data on demographic, socio-economic and parental practices regarding water, sanitation, hygiene, malaria infection and infant and young child feeding were collected, as well as parasitological, biochemical and molecular data. Total and age-stratified multivariate multinomial regression models were fitted to estimate the magnitude of associations between anaemia and its determinants.

RESULTS

Anaemia was found in 44.4% of children, of which 46.0% had IDA. Overall, regression models associated IDA with age, gender and inflammation and non-IDA with age, zinc deficiency and overload, P. falciparum infection, sickle cell trait/anaemia. Among 6-to-23-month-old children IDA was associated with continued breastfeeding and among 24-to-36-month-old children IDA was associated with stunting. Furthermore, zinc deficiency was associated with non-IDA among both age groups children. Inflammation was associated with IDA and non-IDA in either 6-to-23 and 24-to-36 months old children.

CONCLUSION

The main variables associated with IDA and non-IDA within this geographic setting were commonly reported in Africa, but not specifically associated with anaemia. Additionally, the associations of anaemia with inflammation, zinc deficiency and infections could be suggesting the occurrence of nutritional immunity and should be further investigated. In age groups, zinc overload was observed to protect under 6 months children from Non-IDA, while continued breastfeeding was associated with increased IDA prevalence in 6-to-23 months children, and stunting was suggested to increase the odds of IDA in 24-to-36 month children. This site-specific aetiology profile provides an essential first set of evidences able to inform the planification of preventive and corrective actions/programs. Nevertheless, regional and country representative data is needed.

Outer retina changes on optical coherence tomography in vitamin A deficiency

Background

Vitamin A deficiency is rare in the United States and can be missed in patients with malabsorption syndromes without a high dose of suspicion. Ocular complications of hypovitaminosis A include xerosis and nyctalopia, and to a lesser extent reduction in visual acuity and color vision. Outer retinal changes, as seen on spectral domain optic coherence tomography (SD-OCT), in patients with vitamin A deficiency have previously not been documented.

Case presentation

We present two cases with symptoms of severe nyctalopia who were subsequently diagnosed with severe Vitamin A deficiency and their unique findings on SD-OCT of outer nuclear layer diffuse thinning with irregular appearance of the interdigitating zone and the ellipsoid zone as well as normalization after vitamin A supplementation.

Conclusions

Outer nuclear layer thinning and disruption of the outer retinal bands on SD-OCT are reversible with correction of vitamin A deficiency. Improvement in visual acuity, color vision, and nyctalopia are possible with early diagnosis and appropriate treatment.