Effects of Iron on Vitamin D Metabolism: A Systematic Review

Micronutrient Status During Military Training and Associations With Musculoskeletal Health, Injury, and Readiness Outcomes

OBJECTIVE

Micronutrient status, specifically vitamin D and iron, represent modifiable factors for optimizing military readiness. The primary purpose of this investigation was to determine associations between micronutrient deficiency (i.e., iron status and 25-hydroxy-vitamin D [25(OH)D]) and operationally relevant outcomes (i.e., skeletal health, musculoskeletal injury) at baseline and post-10 weeks of arduous military training.

METHODS

A total of 227 (177 men, 50 women) Marine Officer Candidates School (OCS) candidates who completed OCS training with complete data sets were included in this analysis. Vitamin D and iron status indicators were collected at two timepoints, pre (baseline) and post OCS. Musculoskeletal outcomes at the mid- and proximal tibial diaphysis were assessed via peripheral quantitative computed tomography.

RESULTS

Micronutrient status declined following OCS training in men and women and was associated with musculoskeletal outcomes including greater bone strength (strength strain index) at the mid-diaphysis site in those with optimal status (M = 38.26 mm3, SE = 15.59) versus those without (M = -8.03 mm3, SE = 17.27). In women (p = .037), endosteal circumference was greater in the deficient group (M = 53.26 mm, SE = 1.19) compared with the optimal group (M = 49.47 mm, SE = 1.31) at the proximal diaphysis. In men, greater baseline hepcidin concentrations were associated with an increased likelihood of suffering musculoskeletal injury during training.

CONCLUSIONS

Vitamin D and iron status declined over the course of training, suggesting impaired micronutrient status. Differences in musculoskeletal outcomes by micronutrient group suggests optimal vitamin D and ferritin concentrations may exert beneficial effects on bone fatigability and fracture reduction during military training.

Association between anemia and vitamin D deficiency in German seniors : A retrospective data analysis

BACKGROUND

Anemia and deficiency of vitamin D (VDD) are frequently seen in seniors and an association is suspected. Approximately one third of the German population is affected by VDD, with a rising prevalence among seniors.

AIM

To analyze the association between anemia and VDD among German seniors aged ≥ 60 years.

METHODS

Retrospective cross-sectional data analysis (n = 4008) in a nationwide working laboratory medical center (January-December 2019). Study parameters included amongst others: hemoglobin (Hb), calcifediol (25D) and calcitriol (1.25D), glomerular filtration rate (GFR) to assess the kidney disease outcomes quality initiative (KDOQI) state. The inclusion criteria were age ≥ 60 years, normal C‑reactive protein (CRP) and leucocyte levels.

RESULTS

The 25D was estimated in 4008 patients and 1.25D only in 411 patients. Mean age 75 years (± 8.61 years; 60-99 years) with 30.6% males; mean GFR 62 ml/min/1.73 m3 (± 22.74); 20% of patients were anemic, 35% were deficient for 25D (< 50 nmol/l), with men > women (p = 0.014). Linear regression analysis revealed a significant effect of 25D values < 30 nmol/l on hemoglobin in males of KDOQI I-III and females of KDOQI I-IV (R2 = 0.052; p = 0.005; and R2 = 0.124; p < 0.001, respectively). For 1.25D a weak but significant effect on hemoglobin independent of KDOQI was only seen in women (R2 = 0.200; p = 0.005).

CONCLUSION

In this cohort deficiency of 25D and 1.25D was significantly associated with hemoglobin independent of renal function only in women but not in men.

Iron deficiency in athletes: Prevalence and impact on VO2 peak

BACKGROUND

Iron is an important micronutrient in pathways of energy production, adequate nutrient intake and its balance is essential for optimal athletic performance. However, large studies elucidating the impact of iron deficiency on athletes' performance are sparse.

METHODS

Competitive athletes of any age who presented for preparticipation screening 04/2020-10/2021 were included in this study and stratified for iron deficiency (defined as ferritin level <20 µg/l with and without mild anemia [hemoglobin levels ≥11 g/dl]). Athletes with and without iron deficiency were compared and the impact of iron deficiency on athletic performance was investigated.

RESULTS

Overall, 1190 athletes (mean age 21.9 ± 11.6 years; 34.2% females) were included in this study. Among these, 19.7% had iron deficiency. Patients with iron deficiency were younger (18.1 ± 8.4 vs. 22.8 ± 12.1 years, P < 0.001), more often females (64.5% vs. 26.8%, P < 0.001), had lower VO2 peak value (43.4 [38.5/47.5] vs. 45.6 [39.1/50.6]ml/min/kg, P = 0.022) and lower proportion of athletes reaching VO2 peak of >50 ml/min/kg (8.5% vs. 16.1%, P = 0.003). Female sex (OR 4.35 [95% CI 3.13-5.88], P > 0.001) was independently associated with increased risk for iron deficiency. In contrast, the risk for iron deficiency decreased by every life year (OR 0.97 [95% CI 0.95-0.99], P = 0.003). Iron deficiency was independently associated with reduced VO2 peak (OR 0.94 [0.91-0.97], P < 0.001) and lower probability to reach VO2 peak >50 ml/min/kg (OR 0.42 [95% CI 0.25-0.69], P = 0.001).

CONCLUSIONS

Iron deficiency is common in athletes (predominantly in female and in young athletes). Iron deficiency was independently associated with reduced VO2 peak during exercise testing and lower probability to reach a VO2 peak >50 ml/min/kg.

Iron status is associated with tibial structure and vitamin D metabolites in healthy young men

The influence of iron on collagen synthesis and vitamin D metabolism has implications for bone health. This cross-sectional observational study investigated associations between markers of iron status and tibial structure, vitamin D metabolites, and circulating biochemical markers of bone metabolism in young healthy men. A total of 343 male British Army recruits participated (age 22 ± 3 y, height 1.77 ± 0.06 m, body mass 75.5 ± 10.1 kg). Circulating biochemical markers of iron status, vitamin D metabolites, and bone metabolism, and tibial structure and density by high-resolution peripheral quantitative computed tomography scans (HRpQCT) were measured in participants during week 1 of basic military training. Associations between markers of iron status and HRpQCT outcomes, bone metabolism, and vitamin D metabolites were tested, controlling for age, height, lean body mass, and childhood exercise volume. Higher ferritin was associated with higher total, trabecular, and cortical volumetric bone mineral density, trabecular volume, cortical area and thickness, stiffness, and failure load (all p ≤ 0.037). Higher soluble transferrin receptor (sTfR) was associated with lower trabecular number, and higher trabecular thickness and separation, cortical thickness, and cortical pore diameter (all p ≤ 0.033). Higher haemoglobin was associated with higher cortical thickness (p = 0.043). Higher ferritin was associated with lower βCTX, PINP, total 25(OH)D, and total 24,25(OH)2D, and higher 1,25(OH)2D:24,25(OH)2D ratio (all p ≤ 0.029). Higher sTfR was associated with higher PINP, total 25(OH)D, and total 24,25(OH)2D (all p ≤ 0.025). The greater density, size, and strength of the tibia, and lower circulating concentrations of markers of bone resorption and formation with better iron stores (higher ferritin) are likely as a result of the direct role of iron in collagen synthesis.

Fibroblast growth factor 23 is pumping iron: C-terminal-fibroblast growth factor 23 cleaved peptide and its function in iron metabolism

PURPOSE OF REVIEW

Iron deficiency regulates the production of the bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) but also its cleavage, to generate both intact (iFGF23) and C-terminal (Cter)-FGF23 peptides. Novel studies demonstrate that independently of the phosphaturic effects of iFGF23, Cter-FGF23 peptides play an important role in the regulation of systemic iron homeostasis. This review describes the complex interplay between iron metabolism and FGF23 biology.

RECENT FINDINGS

C-terminal (Cter) FGF23 peptides antagonize inflammation-induced hypoferremia to maintain a pool of bioavailable iron in the circulation. A key mechanism proposed is the down-regulation of the iron-regulating hormone hepcidin by Cter-FGF23.

SUMMARY

In this manuscript, we discuss how FGF23 is produced and cleaved in response to iron deficiency, and the principal functions of cleaved C-terminal FGF23 peptides. We also review possible implications anemia of chronic kidney disease (CKD).

Effects of a second iron-dextran injection administered to piglets during lactation on differential gene expression in liver and duodenum at weaning

Six female littermate piglets were used in an experiment to evaluate the mRNA expression in tissues from piglets given one or two 1 mL injections of iron dextran (200 mg Fe/mL). All piglets in the litter were administered the first 1 mL injection < 24 h after birth. On day 7, piglets were paired by weight (mean body weight = 1.72 ± 0.13 kg) and one piglet from each pair was randomly selected as control (CON) and the other received a second injection (+Fe). At weaning on day 22, each piglet was anesthetized, and samples of liver and duodenum were taken from the anesthetized piglets and preserved until mRNA extraction. differential gene expression data were analyzed with a fold change cutoff (FC) of |1.2| P < 0.05. Pathway analysis was conducted with Z-score cutoff of P < 0.05. In the duodenum 435 genes were significantly changed with a FC ≥ |1.2| P < 0.05. In the duodenum, Claudin 1 and Claudin 2 were inversely affected by + Fe. Claudin 1 (CLDN1) plays a key role in cell-to-cell adhesion in the epithelial cell sheets and was upregulated (FC = 4.48, P = 0.0423). Claudin 2 (CLDN2) is expressed in cation leaky epithelia, especially during disease or inflammation and was downregulated (FC = -1.41, P = 0.0097). In the liver, 362 genes were expressed with a FC ≥ |1.2| P < 0.05. The gene most affected by a second dose of 200 mg Fe was hepcidin antimicrobial peptide (HAMP) with a FC of 40.8. HAMP is a liver-produced hormone that is the main circulating regulator of Fe absorption and distribution across tissues. It also controls the major flows of Fe into plasma by promoting endocytosis and degradation of ferroportin (SLC4A1). This leads to the retention of Fe in Fe-exporting cells and decreased flow of Fe into plasma. Gene expression related to metabolic pathway changes in the duodenum and liver provides evidence for the improved feed conversion and growth rates in piglets given two iron injections preweaning with contemporary pigs in a companion study. In the duodenum, there is a downregulation of gene clusters associated with gluconeogenesis (P < 0.05). Concurrently, there was a decrease in the mRNA expression of genes for enzymes required for urea production in the liver (P < 0.05). These observations suggest that there may be less need for gluconeogenesis, and possibly less urea production from deaminated amino acids. The genomic and pathway analyses provided empirical evidence linking gene expression with phenotypic observations of piglet health and growth improvements.

Applying data mining techniques to predict vitamin D deficiency in diabetic patients

Vitamin D is among the vitamins necessary for both adults' and children's health. It plays a significant role in calcium absorption, the immune system, cell proliferation and differentiation, bone protection, skeletal health, rickets, muscle health, heart health, disease pathogenesis and severity, glucose metabolism, glucose intolerance, varying insulin secretion, and diabetes. Because the 25-hydroxyvitamin D (25OHD) test, which is used to measure vitamin D is expensive and may not be covered in healthcare benefits in many countries, this study aims to predict vitamin D deficiency in diabetic patients. The prediction method is based on data mining techniques combined with feature selection by using historical electronic health records. The results were compared with a filter-based feature selection algorithm, namely relief-F. Non-valuable features were eliminated effectively with the relief-F feature selection method without any performance loss in classification. The performances of the methods were evaluated using classification accuracy (ACC), sensitivity, specificity, F1-score, precision, kappa results, and receiver operating characteristic (ROC) curves. The analyses have been conducted on a vitamin D dataset of diabetic patients and the results show that the highest classification accuracy of 97.044% was obtained for the support vector machines (SVM) model using radial kernel that contains 18 features.

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.

Patterns of 25-Hydroxyvitamin D3, Calcium Status, and Anemia in the Saudi Population: A Cross-Sectional Study

BACKGROUND

Emerging evidence suggests an intricate relationship between vitamin D, Ca²⁺, and inflammation-driven anemia. We, thus, investigated the patterns of serum 25(OH)D₃, Ca²⁺, ferritin, and iron in healthy and anemic members of the Saudi population.

METHODS

A population-based, retrospective, cross-sectional study was designed to analyze data for 14,229 subjects, aged 3-110 years, obtained from Al-Borg Medical Laboratories, over a six-year period (2014-2020). Gender and age differences were analyzed for 25(OH)D₃, Ca²⁺, hemoglobin, ferritin, and iron.

RESULTS

Vitamin D deficiency was extremely prevalent (98.47%) irrespective of age or gender, despite an increasing trend with age, in clear contrast to serum Ca²⁺. Ferritin was significantly lower in young adult and adult females, compared to elderly females, whereas iron was significantly reduced in females; in particular, adult females compared to young adults or elderly adults. Only anemic adult males had significantly lower 25(OH)D₃, while Ca²⁺ was consistently significantly diminished in anemics of all age groups, independent of gender. Notably, hypocalcemic subjects were 2.36 times more likely to be anemic. Moreover, ferritin, but not iron, was significantly diminished in anemics, which was only evident in young adults and adults. However, both ferritin and iron showed positive correlation with hematocrit, hemoglobin, MCH, MCHC, and MCV.

CONCLUSIONS

Despite being significantly lower in anemics, 25(OH)D₃ is not particularly associated with anemia, while hypocalcemia is associated with an increased risk for anemia. Assessment of vitamin D and Ca²⁺ status may be valuable in the clinical management of anemia in the Saudi population.

Multiple Indicators of Undernutrition, Infection, and Inflammation in Lactating Women Are Associated with Maternal Iron Status and Infant Anthropometry in Panama: The MINDI Cohort

Maternal infections, nutrient deficiencies, and inflammation (MINDI) co-exist in lactating indigenous women in Panama, but their impact on maternal iron status and infant growth is unknown. For this secondary analysis of cross-sectional data of lactating mothers from our MINDI cohort, we investigated associations of MINDI variables with maternal anemia, elevated serum transferrin receptor (sTfR), low serum iron, hepcidin, ferritin, and infant weight-for-age (WAZ), length-for-age (LAZ), and head-circumference-for-age (HCAZ) Z-scores in 99 mother-infant dyads. A bootstrapping resampling procedure preselected covariates for inclusion in multivariable regressions models from chronic maternal infections and nutritional status [folate, vitamins A, D, retinol-binding protein (RBP), insulin-growth factor-1 (IGF-1)] and inflammation [C-reactive protein (CRP), cytokines, platelet indices] indicators. Anemia was prevalent (53.5%) but underestimated due to widespread low plasma volume (<2.2 L, 79.9%) and was associated with indicators of malnutrition [lower IGF-1, body mass index (BMI), vitamin D, and intake of green/leafy vegetables], but not inflammation. Higher CRP was associated with lower serum iron, and higher hepcidin and ferritin, whereas maternal platelets were associated with lower HCAZ (β = −0.22), WAZ (β = −0.17), and LAZ (β = −0.17). Higher LAZ was also associated with maternal serum vitamin D (β = 0.23), whereas maternal iron supplementation lowered LAZ (β = −0.22). Assessment of iron status in this MINDI cohort is complex and supplementation strategies must consider consequences for both the mother and the infant.

Iron Deficiency Anemia: Efficacy and Limitations of Nutritional and Comprehensive Mitigation Strategies

Iron deficiency anemia (IDA) has reached epidemic proportions in developing countries and has become a major global public health problem, affecting mainly 0–5-year-old children and young women of childbearing age, especially during pregnancy. Iron deficiency can lead to life-threatening loss of red blood cells, muscle function, and energy production. Therefore, the pathogenic features associated with IDA are weakness and impaired growth, motor, and cognitive performance. IDA affects the well-being of the young generation and the economic advancement of developing countries, such as India. The imbalance between iron intake/absorption/storage and iron utilization/loss culminates into IDA. However, numerous strategic programs aimed to increase iron intake have shown that improvement of iron intake alone has not been sufficient to mitigate IDA. Emerging critical risk factors for IDA include a composition of cultural diets, infections, genetics, inflammatory conditions, metabolic diseases, dysbiosis, and socioeconomic parameters. In this review, we discuss numerous IDA mitigation programs in India and their limitations. The new multifactorial mechanism of IDA pathogenesis opens perspectives for the improvement of mitigation programs and relief of IDA in India and worldwide.

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

Vitamin D regulates the master iron hormone hepcidin, and iron in turn alters vitamin D metabolism. Although vitamin D and iron deficiency are highly prevalent globally, little is known about their interactions in Africa. To evaluate associations between vitamin D and iron status we measured markers of iron status, inflammation, malaria parasitemia, and 25-hydroxyvitamin D (25(OH)D) concentrations in 4509 children aged 0.3 months to 8 years living in Kenya, Uganda, Burkina Faso, The Gambia, and South Africa. Prevalence of iron deficiency was 35.1%, and prevalence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D concentrations of <30 nmol/L and <50 nmol/L, respectively. Children with 25(OH)D concentrations of <50 nmol/L had a 98% increased risk of iron deficiency (OR 1.98 [95% CI 1.52, 2.58]) compared to those with 25(OH)D concentrations >75 nmol/L. 25(OH)D concentrations variably influenced individual markers of iron status. Inflammation interacted with 25(OH)D concentrations to predict ferritin levels. The link between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African children.

Iron and 25-hydroxyvitamin D in postmenopausal women with osteoporosis

Iron and vitamin D deficiencies are some of the most common health problems in the world. Iron is essential in oxygen transport and participates in many enzymatic systems in the body, with important roles in vitamin D metabolism. Osteoporosis is one of the most prevalent chronic disease of the elderly in the world as well as in the Saudi population. The relationship between iron, vitamin D deficiency and bone health comes from clinical observations in iron overload patients who suffered bone loss. The opposite scenario, whether iron and vitamin D deficiencies affect bone metabolism, has not been fully addressed. This is of great interest, as this nutrient deficiency is a worldwide public health problem and at the same time osteoporosis and bone alterations are highly prevalent. The relationship between 25(OH)D and iron deficiencies with osteoporosis is unknown up to date. This review presents the current knowledge on nutritional iron and vitamin D deficiencies in bone remodeling, and discuss the link between iron and bone metabolism among postmenopausal women. Finally, it is hypothesized that chronic iron and vitamin D deficiencies induces bone resorption and risk of osteoporosis, thus complete recovery from anemia and its prevention should be promoted in order to improve quality of life including bone health. Several mechanisms are implicated; hence, further investigation on the possible impact of iron and vitamin D deficiencies on the development of osteoporosis is needed.

Vitamin D deficiency in young children with iron deficiency in Misan province, Iraq

This study aimed to assess vitamin D status and its association with iron status in young Iraqi children. A total of 95 infants and toddlers with iron deficiency (ages ranging from 6 to 24 months) and an equal number of 95 healthy subjects with normal hemoglobin (Hb) and sufficient ferritin level with matching age were included as a control group. A specially designed questionnaire was used to collect data. The cases were classified into iron deficiency (ID) and iron deficiency anemia (IDA) according to hemoglobin and ferritin levels. The cases and control groups were subdivided into vitamin insufficiency (VDI), vitamin D deficiency (VDD), and vitamin D sufficiency groups according to 25-hydroxyvitamin D [25(OH)D] levels. Young children with IDA have significantly lower serum levels of 25(OH) D compared with ID and control groups (p<0.05). According to iron status, VDI and VDD were present in 20% and 70% of IDA, 25.7% and 60%of ID, and 26.3% and 30.5% of control groups, respectively, with a significant difference in vitamin D level (p<0.05) among studied groups. A significant positive correlation (p=0.000) was found between serum ferritin level and 25(OH) D level in studied patients. Young children with severe iron deficiency have a higher prevalence of vitamin D deficiency, and there was a significant positive correlation between serum ferritin level and 25(OH) D levels among studied children.

Vitamin D deficiency and anemia in pregnant women: a systematic review and meta-analysis

CONTEXT

Epidemiological studies suggest an association between vitamin D deficiency and anemia. Evidence of this relationship in pregnant women, however, is scarce.

OBJECTIVE

The aim of this systematic review was to investigate the association between vitamin D deficiency and gestational anemia through observational studies.

DATA SOURCES

The PubMed, Scopus, Web of Science, ScienceDirect, Embase, and Virtual Health Library databases were searched from inception to April 2021.

STUDY SELECTION

Original articles reporting observational studies that investigated the association between vitamin D deficiency and gestational anemia were included. Articles that did not have an abstract, as well as reviews articles, experimental studies, and editorials, were excluded. Two reviewers independently performed study selection, data extraction, and assessment of study quality. Disagreements between the reviewers were resolved by a third reviewer.

DATA EXTRACTION

Study quality was assessed by 2 scales. Data were extracted from eligible studies and arranged in a 2 × 2 table. Odds ratios with 95% confidence intervals for the risk of the outcome were estimated using a fixed-effect model.

RESULTS

In total, 985 studies were retrieved, of which 17 were included in the systematic review: 11 cohort studies, 3 case-control studies, and 3 cross-sectional studies. For the meta-analysis, 8 studies with a total of 6530 women were included. There was a 61% increase in the odds of anemia in pregnant women with vitamin D deficiency (OR = 1.61; 95%CI, 1.41-1.83; I2 = 48%).

CONCLUSIONS

Vitamin D deficiency may be a risk factor for anemia in pregnant women.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020182697.

Rapid and Effective Vitamin D Supplementation May Present Better Clinical Outcomes in COVID-19 (SARS-CoV-2) Patients by Altering Serum INOS1, IL1B, IFNg, Cathelicidin-LL37, and ICAM1

Background: We aimed to establish an acute treatment protocol to increase serum vitamin D, evaluate the effectiveness of vitamin D3 supplementation, and reveal the potential mechanisms in COVID-19. Methods: We retrospectively analyzed the data of 867 COVID-19 cases. Then, a prospective study was conducted, including 23 healthy individuals and 210 cases. A total of 163 cases had vitamin D supplementation, and 95 were followed for 14 days. Clinical outcomes, routine blood biomarkers, serum levels of vitamin D metabolism, and action mechanism-related parameters were evaluated. Results: Our treatment protocol increased the serum 25OHD levels significantly to above 30 ng/mL within two weeks. COVID-19 cases (no comorbidities, no vitamin D treatment, 25OHD <30 ng/mL) had 1.9-fold increased risk of having hospitalization longer than 8 days compared with the cases with comorbidities and vitamin D treatment. Having vitamin D treatment decreased the mortality rate by 2.14 times. The correlation analysis of specific serum biomarkers with 25OHD indicated that the vitamin D action in COVID-19 might involve regulation of INOS1, IL1B, IFNg, cathelicidin-LL37, and ICAM1. Conclusions: Vitamin D treatment shortened hospital stay and decreased mortality in COVID-19 cases, even in the existence of comorbidities. Vitamin D supplementation is effective on various target parameters; therefore, it is essential for COVID-19 treatment.

Changes in Bone Turnover, Inflammatory, Oxidative Stress, and Metabolic Markers in Women Consuming Iron plus Vitamin D Supplements: a Randomized Clinical Trial

We aimed to investigate whether combination of vitamin D and iron supplementation, comparing vitamin D alone, could modify bone turnover, inflammatory, oxidative stress, and metabolic markers. Eighty-seven women with hemoglobin (Hb) ≤ 12.7 g/dL and 25OHD ≤ 29 ng/mL vitamin D deficiency/insufficiency aged 18-45 years were randomly assigned into two groups: (1) receiving either 1000 IU/day vitamin D3 plus 27 mg/day iron (D-Fe); (2) vitamin D3 plus placebo supplements (D-P), for 12 weeks. In D-Fe group, significant decrease in red blood cells (RBC) (P = 0.001) and hematocrit (Hct) (P = 0.004) and increases in mean corpuscular hemoglobin concentration (MCHC) (P = 0.001), 25OHD (P < 0.001), osteocalcin (P < 0.001), high-density cholesterol (HDL) (P = 0.041), and fasting blood sugar (FBS) (P < 0.001) were observed. D-P group showed significant decrease in RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), mean corpuscular volume (MCV) (P = 0.004), mean corpuscular hemoglobin (MCH) (P < 0.001), MCHC (P = 0.005), serum ferritin (P < 0.001), and low-density cholesterol (LDL) (P = 0.016) and increases of 25OHD (P < 0.001), osteocalcin (P < 0.001), C-terminal telopeptide (CTX) (P = 0.025), triglyceride (TG) (P = 0.004), FBS (P < 0.001), and interleukin-6 (IL-6) (P = 0.001) at week 12. After the intervention, the D-P group had between-group increases in mean change in the osteocalcin (P = 0.007) and IL-6 (P = 0.033), and decreases in the RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), and MCV (P = 0.001), compared with the D-Fe group. There were significant between-group changes in MCH (P < 0.001), MCHC (P < 0.001), ferritin (P < 0.001), and serum iron (P = 0.018). Iron-vitamin D co-supplementation does not yield added benefits for improvement of bone turnover, inflammatory, oxidative stress, and metabolic markers, whereas, vitamin D alone may have some detrimental effects on inflammatory and metabolic markers. IRCT registration number: IRCT201409082365N9.

The Association Between Ferritin and Vitamin D Levels in Premenopausal Fibroid Uterus Cases With Anemia

Objective

The present study aimed to evaluate the association between serum ferritin and vitamin D levels in fibroid uterus cases presenting with anemia.

Methods

Sixty premenopausal women with uterine fibroids (30 associated with anemia and 30 without anemia) were enrolled as cases and control. All participants were evaluated on the basis of a questionnaire, which included queries related to obstetric, medical, and sociodemographic history. Peripheral blood smear, complete blood count (CBC), hemoglobin (Hb), and serum ferritin concentration were measured by a fully automated analyzer, and 25(OH) vitamin D level was measured by enzyme-linked immunosorbent assay (ELISA).

Results

There was a significant difference in ferritin levels between cases and control (p<0.001). The exposure to sunlight was moderate (one-hour exposure) in all subjects, eliminating the confounding effect of sunlight exposure influencing vitamin D levels. The median vitamin D level in cases was 5.0 ng/ml [interquartile range (IQR): 4.8], and that in control was 18.4 ng/ml (IQR: 7.9; p<0.001). A strong positive correlation of (r)=0.616 (p<0.001) was found between serum ferritin and vitamin D levels.

Conclusion

Fibroid uterus cases with anemia are more prone to vitamin D deficiency as compared to cases without anemia. Vitamin D estimation in fibroid uterus cases presenting with anemia would be useful for better patient management.

Prevalence and Predictors of Vitamin D Deficiency and Insufficiency among Pregnant Rural Women in Bangladesh

Although adequate vitamin D status during pregnancy is essential for maternal health and to prevent adverse pregnancy outcomes, limited data exist on vitamin D status and associated risk factors in pregnant rural Bangladeshi women. This study determined the prevalence of vitamin D deficiency and insufficiency, and identified associated risk factors, among these women. A total of 515 pregnant women from rural Bangladesh, gestational age ≤ 20 weeks, participated in this cross-sectional study. A separate logistic regression analysis was applied to determine the risk factors of vitamin D deficiency and insufficiency. Overall, 17.3% of the pregnant women had vitamin D deficiency [serum 25(OH)D concentration <30.0 nmol/L], and 47.2% had vitamin D insufficiency [serum 25(OH)D concentration between 30–<50 nmol/L]. The risk of vitamin D insufficiency was significantly higher among nulliparous pregnant women (OR: 2.72; 95% CI: 1.75–4.23), those in their first trimester (OR: 2.68; 95% CI: 1.39–5.19), anaemic women (OR: 1.53; 95% CI: 0.99–2.35; p = 0.056) and women whose husbands are farmers (OR: 2.06; 95% CI: 1.22–3.50). The risk of vitamin deficiency was significantly higher among younger pregnant women (<25 years; OR: 2.12; 95% CI: 1.06–4.21), nulliparous women (OR: 2.65; 95% CI: 1.34–5.25), women in their first trimester (OR: 2.55; 95% CI: 1.12–5.79) and those with sub-optimal vitamin A status (OR: 2.30; 95% CI: 1.28–4.11). In conclusion, hypovitaminosis D is highly prevalent among pregnant rural Bangladeshi women. Parity and gestational age are the common risk factors of vitamin D deficiency and insufficiency. A husband’s occupation and anaemia status might be important predictors of vitamin D insufficiency, while younger age and sub-optimal vitamin A status are risk factors for vitamin D deficiency in this population.

Iron overload and Hepcidin overexpression could play a key role in COVID infection, and may explain vulnerability in elderly, diabetics, and obese patients

BACKGROUND

The COVID epidemic hit like a tsunami worldwide. At the time of its arrival in Italy, available literary data were meager, and most of them concerned its epidemiology. World Health Organization proposed guidelines in march 2020, a strategy of treatment has been developed, and a significant number of subsequent articles have been published to understand, prevent, and cure COVID patients.

METHODS

From the observation of two patients, we performed a careful analysis of scientific literature to unearth the relation between COVID infection, clinical manifestations as pneumonia and thrombosis, and to find out why it frequently affects obese, diabetics, and elderly patients.

RESULTS

The analysis shows that hepcidin could represent one of such correlating factors. Hepcidin is most elevated in older age, in non-insulin diabetics patients and in obese people. It is the final target therapy of many medicaments frequently used. Viral disease, and in particular SARS-CoV19, could induce activation of the hepcidin pathway, which in turn is responsible for an increase in the iron load. Excess of iron can lead to cell death by ferroptosis and release into the bloodstream, such as free iron, which in turn has toxic and pro-coagulative effects.

CONCLUSIONS

Overexpression of hepcidin and iron overload might play a crucial role in COVID infection, becoming potential targets for treatment. Hepcidin could also be considered as a biomarker to measure the effectiveness of our treatments and the restoration of iron homeostasis the final intent. (www.actabiomedica.it).

The Effect of Serum 25-Hydroxyvitamin D on Serum Ferritin Concentrations: A Longitudinal Study of Participants of a Preventive Health Program

Various studies have suggested a role of vitamin D in inflammation. However, its effect on ferritin, a biomarker of inflammation, has received relatively little attention. Therefore, we aimed to assess the association of serum 25-hydroxyvitamin D (25(OH)D) with serum ferritin (SF) concentrations, and to examine whether temporal increases in serum 25(OH)D concentrations are paralleled by a reduction in SF concentrations. Data from a community sample of Canadian adults who participated in a preventive health program (n = 6812) were analyzed. During the follow-up, serum 25(OH)D concentrations increased from 80.7 to 115.0 nmol/L whereas SF concentrations decreased from 122.0 to 92.0 µg/L (median follow-up time was 11.67 months). Cross-sectional analyses revealed that compared to participants with 25(OH)D concentrations of <50 nmol/L, those with 25(OH)D concentrations of 75 to <100, 100 to <125, and ≥125 nmol/L had SF concentrations that were 13.00, 23.15, and 27.59 µg/L lower respectively (p < 0.001). Compared to those without temporal improvements in 25(OH)D concentrations between baseline and follow-up, participants who improved their 25(OH)D concentrations with ≥50 nmol/L decreased their SF concentrations with 5.71 µg/L. For participants for whom the increase in 25(OH)D concentrations was less than 50 nmol/L, decreases in SF concentrations were less pronounced and not statistically significant. These observations suggest that despite strong associations between 25(OH)D and SF concentrations, interventions aiming to lower SF concentrations through sun-exposure and vitamin D supplementation should target substantial increases in 25(OH)D concentrations.

Vitamin D Supplementation Modestly Reduces Serum Iron Indices of Healthy Arab Adolescents

Vitamin D deficiency has been shown to affect iron status via decreased calcitriol production, translating to decreased erythropoiesis. The present study aimed to determine for the first time whether vitamin D supplementation can affect iron levels among Arab adolescents. A total of 125 out of the initial 200 Saudi adolescents with vitamin D deficiency (serum 25(OH)D < 50 nmol/L) were selected from the Vitamin D-School Project of King Saud University in Riyadh, Saudi Arabia. Cluster randomization was done in schools, and students received either vitamin D tablets (1000 IU/day) (N = 53, mean age 14.1 ± 1.0 years) or vitamin D-fortified milk (40IU/200mL) (N = 72, mean age 14.8 ± 1.4 years). Both groups received nutritional counseling. Anthropometrics, glucose, lipids, iron indices, and 25(OH)D were measured at baseline and after six months. Within group analysis showed that post-intervention, serum 25(OH)D significantly increased by as much as 50%, and a parallel decrease of −42% (p-values <0.001 and 0.002, respectively) was observed in serum iron in the tablet group. These changes were not observed in the control group. Between-group analysis showed a clinically significant increase in serum 25(OH)D (p = 0.001) and decrease in iron (p < 0.001) in the tablet group. The present findings suggest a possible inhibitory role of vitamin D supplementation in the iron indices of healthy adolescents whose 25(OH)D levels are sub-optimal but not severely deficient, implying that the causal relationship between both micronutrients may be dependent on the severity of deficiency, type of iron disorder, and other vascular conditions that are known to affect hematologic indices. Well-designed, randomized trials are needed to confirm the present findings.

The Association between Iron and Vitamin D Status in Female Elite Athletes

Vitamin D may influence iron metabolism and erythropoiesis, whereas iron is essential for vitamin D synthesis. We examined whether vitamin D deficiencies (VDD) are associated with reduced iron status and whether progressive iron deficiency (ID) is accompanied by inferior vitamin D status. The study included 219 healthy female (14–34 years old) athletes. VDD was defined as a 25(OH)D concentration < 75 nmol/L. ID was classified based on ferritin, soluble transferrin receptor (sTfR), total iron binding capacity (TIBC) and blood morphology indices. The percentage of ID subjects was higher (32%) in the VDD group than in the 25(OH)D sufficient group (11%) (χ² = 10.6; p = 0.001). The percentage of VDD subjects was higher (75%) in the ID than in the normal iron status group (48%) (χ² = 15.6; p = 0.001). The odds ratios (ORs) for VDD increased from 1.75 (95% CI 1.02–2.99; p = 0.040) to 4.6 (95% CI 1.81–11.65; p = 0.001) with progressing iron deficiency. ID was dependent on VDD in both VDD groups (25(OH)D < 75 and < 50 nmol/L). The ID group had a lower 25(OH)D concentration (p = 0.000). The VDD group had lower ferritin (p = 0.043) and iron (p = 0.004) concentrations and higher values of TIBC (p = 0.016) and sTfR (p = 0.001). The current results confirm the association between vitamin D and iron status in female athletes, although it is difficult to assess exactly which of these nutrients exerts a stronger influence over the other.

Iron deficiency beyond erythropoiesis: should we be concerned?

OBJECTIVE

To consider the key implications of iron deficiency for biochemical and physiological functions beyond erythropoiesis.

METHODS

PubMed was searched for relevant journal articles published up to August 2017.

RESULTS

Anemia is the most well-recognized consequence of persisting iron deficiency, but various other unfavorable consequences can develop either before or concurrently with anemia. Mitochondrial function can be profoundly disturbed since iron is a cofactor for heme-containing enzymes and non-heme iron-containing enzymes in the mitochondrial electron transport chain. Biosynthesis of heme and iron-sulfur clusters in the mitochondria is inhibited, disrupting synthesis of compounds such as hemoglobin, myoglobin, cytochromes and nitric oxide synthase. The physiological consequences include fatigue, lethargy, and dyspnea; conversely, iron repletion in iron-deficient individuals has been shown to improve exercise capacity. The myocardium, with its high energy demands, is particularly at risk from the effects of iron deficiency. Randomized trials have found striking improvements in disease severity in anemic but also non-anemic chronic heart failure patients with iron deficiency after iron therapy. In vitro and pre-clinical studies have demonstrated that iron is required by numerous enzymes involved in DNA replication and repair, and for normal cell cycle regulation. Iron is also critical for immune cell growth, proliferation, and differentiation, and for specific cell-mediated effector pathways. Observational studies have shown that iron-deficient individuals have defective immune function, particularly T-cell immunity, but more evidence is required. Pre-clinical models have demonstrated abnormal myelogenesis, brain cell metabolism, neurotransmission, and hippocampal formation in iron-deficient neonates and young animals. In humans, iron deficiency anemia is associated with poorer cognitive and motor skills. However, the impact of iron deficiency without anemia is less clear.

CONCLUSION

The widespread cellular and physiological effects of iron deficiency highlight the need for early detection and treatment of iron deficiency, both to ameliorate these non-erythropoietic effects, and to avoid progression to iron deficiency anemia.

Vitamin D deficiency and anemia risk in children: a review of emerging evidence

There has been renewed scientific interest in the sequelae of vitamin D deficiency, given the emerging evidence on the diverse biologic functions of vitamin D, besides its fundamental role in bone and mineral metabolism. For the past decade, the evidence in the medical literature pointing to a relationship between anemia risk and vitamin D deficiency has been accumulating. This paper critically reviews the current evidence linking vitamin D deficiency to anemia risk in children. The synthesized evidence indicates that the studies, which were preponderantly conducted among the adult population, not only reported a bidirectional relationship between vitamin D deficiency and anemia but also showed a racial effect. In studies conducted among children, similar results were reported. Although the causal association of vitamin D deficiency with anemia risk (especially iron-deficiency anemia) remains debatable, the noncalcemic actions of the vitamin and its analogs hold prospects for several novel clinical applications. There is, however, unanimity in many reports suggesting that vitamin D deficiency is directly associated with anemia of chronic disease or inflammation. Despite the advances in unraveling the role of vitamin D in iron homeostasis, further research is still required to validate causality in the relationship between vitamin D deficiency and anemia, as well as to determine its optimal dosing, the ideal recipients for therapeutic intervention, and the preferred analogs to administer.