Vitamin D Deficiency and Its Association with Iron Deficiency in African Children

Association between anaemia and vitamin D insufficiency among 6- to 12-month-old infants: implications for clinical practice

BACKGROUND

Anaemia and vitamin D insufficiency (VDI) are among the most common nutritional problems. Anaemia screening is routinely performed; however, screening for VDI is not usually recommended.

OBJECTIVES

To study the association between anaemia and VDI and identify the risk factors for VDI.

METHODS

We conducted a cross-sectional study of 120 infants aged 6-12 months attending a well-child clinic at Songklanagarind Hospital between December 2020 and November 2021. Sociodemographic data and 24-h food records were also collected. Blood samples were obtained for complete blood count and 25-hydroxyvitamin D [25(OH)D] levels. Logistic regression analysis was used to determine risk factors for VDI.

RESULTS

The mean 25(OH)D level was 22.2 ± 8.9 ng/mL in anaemic infants and 27.2 ± 9.6 ng/mL in non-anaemic infants (P value 0.01). The median (IQR) Hb level was 11.1 g/dL (10.3, 11.4) in the VDI group and 11.4 g/dL (11, 12.1) in the non-VDI group (P value 0.002). The proportion of breastfed infants was higher in infants with anaemia (80%) (P < 0.001) and VDI (85.3%) (P < 0.001). Sunlight exposure <15 min/day (odds ratio [OR] 3.84; 95% confidence interval [CI]: 1.23-12.00; P = 0.020) was a risk factor, and vitamin D intake (OR 0.37; 95% CI: 0.20-0.74; P = 0.004) was a protective factor for VDI.

CONCLUSION

Infants with anaemia, short duration of sunlight exposure, breastfeeding, low vitamin D intake, and low iron intake were more likely to be vitamin D insufficient. However, after adjustment in the multivariate analyses, only sunlight exposure and vitamin D intake were significantly associated with vitamin D insufficiency.

Calcium, Phosphate, and Vitamin D in Children and Adolescents with Chronic Diseases: A Cross-Sectional Study

Chronic diseases may affect the nutritional status of children and adolescents. Calcium (Ca), phosphorus (P), and vitamin D (Vit-D) are crucial nutrients for their growth and development. Proper diagnosis and treatment are critical components of personalized and precision medicine. Hence, we conducted a cross-sectional and comparative study to evaluate Ca, P, and Vit-D levels in their non-skeletal functions and their association with health and nutritional biomarkers in children and adolescents with diverse chronic conditions. We performed anthropometric, body composition, clinical evaluation, biochemical analysis, and dietary survey methods. A total of 78 patients (1-19 years, 43 females, 42 children) took part in this study. Overall, 24, 30, and 24 participants were obese, undernourished, and eutrophic, respectively. Results found that 74% and 35% of individuals had deficient Vit-D and Ca intake, respectively. Most cases were normocalcemic. Results also found that 47% of the subjects had Vit-D deficiency (VDD), 37% were insufficient, and 37% had hypophosphatemia. Of the 46% and 31% of patients with VDD and insufficient levels, 19% and 11% were hypophosphatemic, respectively. Calcium, P, and Vit-D levels were associated with anthropometric parameters, body mass index, body composition, physical activity, diet, growth hormones, and the immune, liver, and kidney systems. These results show the coincident risk of altered Ca, P, and Vit-D metabolism in children and adolescents with chronic diseases.

Nutritional Modulation of Hepcidin in the Treatment of Various Anemic States

Twenty years after its discovery, hepcidin is still considered the main regulator of iron homeostasis in humans. The increase in hepcidin expression drastically blocks the flow of iron, which can come from one's diet, from iron stores, and from erythrophagocytosis. Many anemic conditions are caused by non-physiologic increases in hepcidin. The sequestration of iron in the intestine and in other tissues poses worrying premises in view of discoveries about the mechanisms of ferroptosis. The nutritional treatment of these anemic states cannot ignore the nutritional modulation of hepcidin, in addition to the bioavailability of iron. This work aims to describe and summarize the few findings about the role of hepcidin in anemic diseases and ferroptosis, as well as the modulation of hepcidin levels by diet and nutrients.

Maternal prenatal, with or without postpartum, vitamin D3 supplementation does not improve maternal iron status at delivery or infant iron status at 6 months of age: secondary analysis of a randomised controlled trial

Background

Vitamin D may modify iron status through regulation of hepcidin and inflammatory pathways. This study aimed to investigate effects of maternal vitamin D supplementation on iron status in pregnancy and early infancy.

Methods

In a trial in Dhaka, Bangladesh, women (n=1300) were randomised to one of five vitamin D3 regimens from 17 to 24 weeks' gestation until 26 weeks postpartum (prenatal; postpartum doses): 0;0, 4200;0, 16 800;0, 28 000;0 or 28 000;28 000 IU/week. All participants received standard iron-folic acid supplementation. In this secondary analysis (n=998), we examined effects of prenatal;postpartum vitamin D on serum ferritin and other biomarkers of maternal iron status (transferrin saturation, total iron binding capacity, soluble transferrin receptor and hepcidin) at delivery, and infant ferritin and haemoglobin at 6 months of age. Using linear regression, we estimated per cent mean differences between each intervention group and placebo with 95% CIs, with and without adjustment for baseline ferritin or inflammatory biomarkers (C reactive protein and α-1-acid glycoprotein (AGP)).

Results

At delivery, ferritin concentrations were similar between each intervention group and placebo in unadjusted (n=998) and baseline ferritin-adjusted analyses (n=992; p>0.05). Compared with placebo, AGP was lower in each intervention group (per cent difference (95% CI) = -11% (-21 to -1.0), -14% (-23 to -3.5) and -11% (-19 to -2.0) in the 4200 IU/week, 16 800 IU/week and 28 000 IU/week groups, respectively; n=779). In the subgroup of women with baseline 25-hydroxyvitamin D < 30 nmol/L, ferritin was lower in each intervention group versus placebo (-23% (-37 to -5.0), -20% (-35 to -1.9) and -20% (-33 to -4.1) in the 4200 IU/week, 16 800 IU/week and 28 000 IU/week groups, respectively; n=645); effects were slightly attenuated after adjustment for inflammation (n=510). There were no effects of vitamin D on other iron biomarkers among women at delivery or infants aged 6 months.

Conclusion

These findings do not support improvement of iron status by vitamin D. The effect of prenatal vitamin D supplementation on ferritin may reflect an anti-inflammatory mechanism.

Interplay of Vitamin D, Unfolded Protein Response, and Iron Metabolism in Neuroblastoma Cells: A Therapeutic Approach in Neurodegenerative Conditions

Vitamin D3 (VD) is crucial for various cell functions, including gene regulation, antioxidant defense, and neural health. Neurodegenerative conditions are closely linked to the unfolded protein response (UPR), a mechanism reacting to endoplasmic reticulum (ER) stress. Iron metabolism is intricately associated with UPR and neurodegeneration. This study used SH-SY5Y neuroblastoma cells to investigate the relationship between UPR, iron metabolism, and VD. Different sequences of treatments (pre- and post-treatments) were applied using VD and thapsigargin (Tg), and various methods were used for evaluation, including real-time qPCR, Western blotting, ELISA, and iron content analysis. The findings indicate that VD affects UPR pathways, cytokine release, and iron-related genes, potentially offering anti-inflammatory benefits. It also influences iron transporters and storage proteins, helping to maintain cellular iron balance. Furthermore, pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα) were impacting UPR activation in cells. VD also influenced fractalkine (CX3CL1) gene expression and secretion, suggesting its potential as a therapeutic agent for addressing neuroinflammation and iron dysregulation. This research provides insights into the intricate connections among VD, UPR, and iron metabolism in SH-SY5Y neuroblastoma cells, with implications for future investigations and potential therapeutic approaches in neurodegenerative diseases characterized by UPR dysregulation and iron accumulation.

Blood Levels of Environmental Heavy Metals are Associated with Poorer Iron Status in Ugandan Children: A Cross-Sectional Study

BACKGROUND

Iron deficiency (ID) and environmental exposure to metals frequently co-occur among Ugandan children, but little is known about their associations, although iron and other divalent metals share the same intestinal absorption transporter, divalent metal transporter 1 (DMT1).

OBJECTIVES

We examined associations between iron status and blood concentrations of lead, manganese (Mn), cobalt (Co), and cadmium, both singly and as a mixture.

METHODS

We used data on sociodemographic status, iron biomarkers, and blood concentrations of heavy metals collected from a cross-sectional survey of 100 children aged 6-59 mo in Kampala, Uganda. We compared blood concentrations of metals in ID with iron-sufficient children. We examined associations between a metal mixture and iron biomarkers using multiple linear regression and weighted quintile sum regression.

RESULTS

The median (interquartile range) blood Mn (μg/L) was higher in ID children defined by soluble transferrin receptor (sTfR) and ferritin (ID compared with iron-sufficient children): (sTfR [21.3 {15.1, 28.8}, 11.2 {8.6, 18.5}], ferritin [19.5 {15.0, 27.2}, 11.2 {8.8, 19.6}]; P < 0.001 for both). Similarly, the median (interquartile range) blood Co (μg/L) was higher in ID children by ferritin ([0.5 {0.4, 0.9}, 0.4 {0.3, 0.5}], P = 0.05). Based on the multiple linear regression results, higher blood Co and Mn were associated with poorer iron status (defined by all 4 iron indicators for Co and by sTfR for Mn). The weighted quintile sum regression result showed that higher blood concentrations of a metal mixture were associated with poorer iron status represented by sTfR, ferritin, and hepcidin, mainly driven by Co and Mn.

CONCLUSIONS

Our study findings suggest that poorer iron status is associated with overall heavy metal burden, predominantly Co and Mn, among Ugandan children. Further prospective studies should confirm our primary findings and investigate the combined effects of coexposures to neurotoxicants on the neurodevelopment of young children.

Genetic polymorphisms influencing deferasirox pharmacokinetics, efficacy, and adverse drug reactions: a systematic review and meta-analysis

Objective: Deferasirox is an iron-chelating agent prescribed to patients with iron overload. Due to the interindividual variability of deferasirox responses reported in various populations, this study aims to determine the genetic polymorphisms that influence drug responses. Methods: A systematic search was performed from inception to March 2022 on electronic databases. All studies investigating genetic associations of deferasirox in humans were included, and the outcomes of interest included pharmacokinetics, efficacy, and adverse drug reactions. Fixed- and random-effects model meta-analyses using the ratio of means (ROM) were performed. Results: Seven studies involving 367 participants were included in a meta-analysis. The results showed that subjects carrying the A allele (AG/AA) of ABCC2 rs2273697 had a 1.23-fold increase in deferasirox C_max (ROM = 1.23; 95% confidence interval [CI]:1.06-1.43; p = 0.007) and a lower Vd (ROM = 0.48; 95% CI: 0.36-0.63; p < 0.00001), compared to those with GG. A significant attenuated area under the curve of deferasirox was observed in the subjects with UGT1A3 rs3806596 AG/GG by 1.28-fold (ROM = 0.78; 95% CI: 0.60-0.99; p = 0.04). In addition, two SNPs of CYP24A1 were also associated with the decreased C_trough: rs2248359 CC (ROM = 0.50; 95% CI: 0.29-0.87; p = 0.01) and rs2585428 GG (ROM = 0.47; 95% CI: 0.35-0.63; p < 0.00001). Only rs2248359 CC was associated with decreased C_min (ROM = 0.26; 95% CI: 0.08-0.93; p = 0.04), while rs2585428 GG was associated with a shorter half-life (ROM = 0.44; 95% CI: 0.23-0.83; p = 0.01). Conclusion: This research summarizes the current evidence supporting the influence of variations in genes involved with drug transporters, drug-metabolizing enzymes, and vitamin D metabolism on deferasirox responses.

A Cross-Sectional Study of the Associations between Biomarkers of Vitamin D, Iron Status, and Hemoglobin in South African Women of Reproductive Age: the Healthy Life Trajectories Initiative, South Africa

Background

Vitamin D deficiency and anemia impact the health of women of reproductive age. Evidence suggests an inverse relationship between serum vitamin D (25-hydroxyvitamin D [25(OH)D]) and anemia/iron deficiency, but less is known about these associations in women of reproductive age, in particular in a setting with a combined burden of micronutrient deficiency, food insecurity, and obesity.

Objective

We aimed to assess the associations between 25(OH)D and biomarkers of iron and anemia in a cohort of women of reproductive age from Soweto, South Africa. The prevalence of vitamin D deficiency was also assessed.

Methods

In this cross-sectional substudy of the Healthy Life Trajectories Initiative (HeLTI) South Africa pilot trial, 25(OH)D, iron markers (ferritin and soluble transferrin receptor [sTFR]), and altitude-adjusted hemoglobin (Hb) were measured in 493 women aged 18 to 25 years. Associations between iron deficiency/anemia and vitamin D status were evaluated using multivariable logistic regression, adjusting for confounders including fat mass index (FMI). Structural equation modeling (SEM) was performed to evaluate direct and indirect pathways between 25(OH)D, iron and anemia markers, and covariates.

Results

Of 493 participants, 136 (27.6%) had vitamin D insufficiency (25(OH)D ≥12-20 ng/mL), whereas 28 (5.6%) had vitamin D deficiency (<12 ng/mL). Anemia and iron deficiency were not significantly associated with vitamin D category (25(OH)D<20 ng/mL compared with ≥20 ng/mL) in multivariable logistic regression analyses. In SEM, log-transformed 25(OH)D was not significantly associated with Hb, ferritin, or sTFR, but it was significantly associated with season of data collection, hormonal contraceptive use, and FMI (total effects: B = 0.17, 95% CI: 0.104, 0.236, P < 0.001; B: 0.10, 95% CI: 0.041, 0.154, P < 0.001; B: -0.01, 95%CI: -0.016, -0.003, P = 0.003, respectively).

Conclusion

No significant association between vitamin D (25(OH)D), anemia (Hb), and iron markers was found. The inverse relationship between FMI and vitamin D status emphasizes the overlap between adiposity and micronutrient deficiencies in young South African women, exacerbating their risk of disease development.

Associations of Dietary Patterns and Vitamin D Levels with Iron Status in Pregnant Women: A Cross-Sectional Study in Taiwan

Vitamin D is involved in the pathophysiology of anemia. This cross-sectional study was conducted using the Nationwide Nutrition and Health Survey in Pregnant Women in Taiwan database. We investigated associations among dietary patterns (DPs), vitamin D, and iron-related biomarkers in pregnant women. The principal component analysis revealed four DPs. Linear and logistic regression analyses were performed to investigate the association of DPs with anemia-related biomarkers. Plant-based, carnivore, and dairy and nondairy alternatives DPs were positively associated with serum vitamin D levels. After adjusting covariates, the pregnant women consuming plant-based DPs at the mid-tertile (T2) were associated with reduced risks of low serum folate and vitamin D levels, and those consuming carnivore DPs at higher tertiles (T2 and/or T3) were correlated with an increased risk of low serum iron levels but decreased risks of low serum transferrin saturation, vitamin B₁₂, and vitamin D levels. The pregnant women consuming dairy and nondairy alternatives DPs at the highest tertile (T3) were associated with reduced risks of low serum folate and vitamin B₁₂ levels. However, the processed food DP was not correlated with anemia-related biomarkers. Thus, plant-based, carnivore, and dairy and nondairy alternatives DPs were associated with the risk of low-serum-anemia-related variables.