Vitamin B12 deficiency is the primary cause of megaloblastic anaemia in Zimbabwe

Association between anaemia and aflatoxin B1 and fumonisin B1 exposure in HIV-infected and HIV-uninfected pregnant women from Harare, Zimbabwe

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are poisons that contaminate poorly stored staple foods in resource-limited settings. Antenatal AFB1 and FB1 exposure may cause anaemia. We aimed to determine the associations of urinary aflatoxin M1 (AFM1) and FB1, biomarkers of AFB1 and FB1 exposure, respectively, with erythrocyte parameters and anaemia. A retrospective cross-sectional study was conducted in 68 HIV-infected and 61 HIV-uninfected pregnant women ≥ 20 weeks gestational age in Harare, Zimbabwe. AFM1 and FB1 were measured in urine via competitive ELISA, and levels were grouped into tertiles. The erythrocyte parameters assessed were haemoglobin (Hb), mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, red blood cell (RBC), haematocrit (HCT), and red blood cell distribution width. Associations of urinary AFM1 and FB1 with erythrocyte parameters, and anaemia were assessed in a multiple regression controlled for potential confounders. The presence of FB1 in urine decreased Hb levels in all women (β= -0.98, 95% CI: -1.94, 0.02) and HIV-uninfected (β= -1.99, 95% CI: -3.71, -0.26). FB1 tertile 3 decreased Hb levels (β= -0.88, 95% CI: -1.74, 0.01) and HCT levels (β= -2.65, 95% CI: -5.26, 0.03) in HIV-infected. AFM1 tertile 2 decreased RBC levels in HIV-infected (β= -0.34, 95% CI: -0.71, -0.03). The presence of FB1 in urine increased anaemia risk in HIV-uninfected (OR: 10.68 95% CI: 1.02, 112.34). AFM1 tertile 2 increased macrocytic anaemia risk in HIV-infected (OR: 13.72, 95% CI: 0.92, 203.55). There is need to ensure food safety through monitoring and nutritional interventions to improve maternal-infant health outcomes.

Roles of blood metabolites in mediating the relationship between vitiligo and autoimmune diseases: Evidence from a Mendelian randomization study

OBJECTIVE

This study employed Mendelian Randomization (MR) to investigate the causal relationship between genetic susceptibility to vitiligo and the risk of various autoimmune diseases, along with the mediating role of blood metabolites.

METHODS

We performed two-sample MR analyses using aggregated genome-wide association studies (GWAS) data on 486 blood metabolites, vitiligo, and nine autoimmune diseases to investigate blood metabolites' causal effects on the susceptibility of vitiligo and the associations of vitiligo with nine autoimmune comorbidities. We also applied multivariable MR to unravel metabolites by which vitiligo influences the pathogenesis of autoimmune diseases.

RESULTS

Our findings indicate that vitiligo amplified the risk of several autoimmune diseases, including rheumatoid arthritis (OR 1.17; 95 % CI 1.08-1.27), psoriasis (OR 1.10; 95 % CI 1.04-1.17), type 1 diabetes (OR 1.41; 95 % CI 1.23-1.63), pernicious anemia (OR 1.23; 95 % CI 1.12-1.36), autoimmune hypothyroidism (OR 1.19; 95 % CI 1.11-1.26), alopecia areata (OR 1.22; 95 % CI 1.10-1.35), and autoimmune Addison's disease (OR 1.22; 95 % CI 1.12-1.33). Additionally, our analysis identified correlations with vitiligo for 14 known (nine risk, five protective) and seven uncharacterized serum metabolites. After adjusting for genetically predicted levels of histidine and pyruvate, the associations between vitiligo and these diseases were attenuated.

CONCLUSIONS

We substantiated vitiligo's influence on susceptibility to seven autoimmune diseases and conducted a thorough investigation of serum metabolites correlated with vitiligo. Histidine and pyruvate are potential mediators of vitiligo associated with autoimmune diseases.By combining metabolomics with genomics, we provide new perspectives on the etiology of vitiligo and its immune comorbidities.

Ready-to-Use Therapeutic Foods Fail to Improve Vitamin A and Iron Status Meaningfully during Treatment for Severe Acute Malnutrition in 6-59-Month-old Cambodian Children

Severe acute malnutrition (SAM) remains a global health concern. Studies on the impact of ready-to-use therapeutic foods (RUTFs) on micronutrient status during SAM treatment are almost nonexistent. The objective was to investigate the impact of RUTFs on the iron and vitamin A status of 6-59-month-old children receiving SAM treatment. Biomarkers of vitamin A status (retinol-binding protein, RBP), iron status (ferritin and soluble transferrin receptor, sTfR), and inflammation (C-reactive protein, CRP, and alpha-1 acid glycoprotein, AGP) were collected at admission and discharge (week 8) during an RUTF effectiveness trial. Vitamin A deficiency was defined as RBP <0.70 µmol/L, low body iron as body iron (BI) <0 mg/kg and deficient iron stores as ferritin <12 µg/L. Data were available for 110 and 75 children at admission and discharge, respectively. There was no significant difference in haemoglobin, ferritin, sTfR, BI or RBP concentrations between admission and discharge. At discharge, BI was 0.2 mg/kg lower, and there was a tendency towards a slightly lower RBP concentration, but the prevalence of vitamin A deficiency was low at admission and discharge (6% and 3%, respectively). The small impact of both RUTFs on improving vitamin A and iron status during SAM treatment calls for further research on the bioavailability of micronutrients to enhance the effectiveness of SAM treatment on micronutrient status.

Profound Vitamin B12 Deficiency in a 1-Year-Old Child in Botswana: A Call to Initiate Early Empiric Therapy

Vitamin B12 deficiency is a rare diagnosis in young children. We present the case of a 1-year-old Zimbabwean child with profound anemia. Further testing revealed undetectable levels of vitamin B12 and positive intrinsic factor antibodies that were drawn after the initiation of empiric treatment with parenteral vitamin B12. We report the evaluation and management of vitamin B12 deficiency in a resource-limited setting. Vitamin B12 deficiency should be considered in children presenting with unexplained cytopenias with consideration of empiric treatment with parenteral vitamin B12, as developmental and neurological complications of vitamin B12 deficiency can be devastating and permanent.

Metabolic profiling of total homocysteine and related compounds in hyperhomocysteinemia: utility and limitations in diagnosing the cause of puzzling thrombophilia in a family

We describe a family illustrating the diagnostic difficulties occurring when pyridoxine-responsive cystathionine beta-synthase (CBS) deficiency presents with thrombotic disease without associated ocular, skeletal, or CNS abnormalities, a situation increasingly recognized. This family had several thromboembolic episodes in two generations with apparently inconstant elevations of plasma total homocysteine (tHcy). When taking (sometimes even low amounts) of pyridoxine, the affected family members had low-normal tHcy and normal values for cystathionine, methionine, and cysteine. Withdrawal of vitamin therapy was necessary before lower cystathionine, elevated methionine, and decreased cysteine became apparent, a pattern suggestive of CBS deficiency, leading to the finding that the affected members were each compound heterozygotes for CBS p.G307S and p.P49L. To assist more accurate diagnosis of adults presenting with thrombophilia found to have elevated tHcy, the patterns of methionine-related metabolites in CBS-deficient patients are compared in this article to those in patients with homocysteine remethylation defects, including inborn errors of folate or cobalamin metabolism, and untreated severe cobalamin or folate deficiency. Usually serum cystathionine is low in subjects with CBS deficiency and elevated in those with remethylation defects. S-Adenosylmethionine and S-adenosylhomocysteine are often markedly elevated in CBS deficiency when tHcy is above 100 umol/L. We conclude that there are likely other undiagnosed, highly B6-responsive adult patients with CBS deficiency, and that additional testing of cystathionine, total cysteine, methionine, and S-adenosylmethionine will be helpful in diagnosing them correctly and distinguishing CBS deficiency from remethylation defects.

Folate and DNA methylation

SIGNIFICANCE

The progressive, dose-dependent, and potentially reversible epigenetic changes observed in cancer present new opportunities in cancer risk modification and prevention using dietary and lifestyle factors. Folate, a water-soluble B vitamin, has been of intense interest because of an inverse association between folate status and the risk of several malignancies (particularly colorectal cancer) and its potential to modulate DNA methylation. Aberrant patterns and dysregulation of DNA methylation are mechanistically related to carcinogenesis.

RECENT ADVANCES

The effects of folate on DNA methylation patterns have recently been investigated in two important life stages: pre- and early postnatal life and aging. Recent studies have demonstrated that folate exposure in the intrauterine environment and early life and during the aging process may have profound effects on DNA methylation with significant functional ramifications, including the risk of cancer.

CRITICAL ISSUES

Evidence from animal, human, and in vitro studies suggest that the epigenetic effects of folate on DNA methylation are highly complex. The effects are gene and site specific and appear to depend on cell type, target organ, stage of transformation, the degree and duration of folate manipulations, interactions with other methyl group donors and dietary factors, and genetic variants in the folate metabolic pathways.

FUTURE DIRECTIONS

The potential for folate to modulate DNA methylation and, thus, modify the risk of cancer in humans is worthy of further investigation. Due to the complex relationship between folate exposure and DNA methylation, more elaborate epidemiological, clinical, and mechanistic studies that determine the clinical, biological, and molecular effects of folate are warranted.

Anaemia in low-income and middle-income countries

Anaemia affects a quarter of the global population, including 293 million (47%) children younger than 5 years and 468 million (30%) non-pregnant women. In addition to anaemia's adverse health consequences, the economic effect of anaemia on human capital results in the loss of billions of dollars annually. In this paper, we review the epidemiology, clinical assessment, pathophysiology, and consequences of anaemia in low-income and middle-income countries. Our analysis shows that anaemia is disproportionately concentrated in low socioeconomic groups, and that maternal anaemia is strongly associated with child anaemia. Anaemia has multifactorial causes involving complex interaction between nutrition, infectious diseases, and other factors, and this complexity presents a challenge to effectively address the population determinants of anaemia. Reduction of knowledge gaps in research and policy and improvement of the implementation of effective population-level strategies will help to alleviate the anaemia burden in low-resource settings.

Anaemia in pregnancy

Anaemia in pregnancy, defined as a haemoglobin concentration (Hb) < 110 g/L, affects more than 56 million women globally, two thirds of them being from Asia. Multiple factors lead to anaemia in pregnancy, nutritional iron deficiency anaemia (IDA) being the commonest. Underlying inflammatory conditions, physiological haemodilution and several factors affecting Hb and iron status in pregnancy lead to difficulties in establishing a definitive diagnosis. IDA is associated with increased maternal and perinatal morbidity and mortality, and long-term adverse effects in the new born. Strategies to prevent anaemia in pregnancy and its adverse effects include treatment of underlying conditions, iron and folate supplementation given weekly for all menstruating women including adolescents and daily for women during pregnancy and the post partum period, and delayed clamping of the umbilical cord at delivery. Oral iron is preferable to intravenous therapy for treatment of IDA. B12 and folate deficiencies in pregnancy are rare and may be due to inadequate dietary intake with the latter being more common. These vitamins play an important role in embryo genesis and hence any relative deficiencies may result in congenital abnormalities. Finding the underlying cause are crucial to the management of these deficiencies. Haemolytic anaemias rare also rare in pregnancy, but may have life-threatening complications if the diagnosis is not made in good time and acted upon appropriately.

Daily intake of 4 to 7 microg dietary vitamin B-12 is associated with steady concentrations of vitamin B-12-related biomarkers in a healthy young population

BACKGROUND

Studies have questioned whether the current Recommended Dietary Allowance (RDA) of 2.4 microg vitamin B-12/d is adequate.

OBJECTIVE

We examined the association between dietary vitamin B-12 intake and biomarkers of vitamin B-12 status.

DESIGN

Dietary vitamin B-12 intake was estimated, and biomarkers of vitamin B-12 status were measured, in healthy men and women (n = 299; age range: 18-50 y) who were recruited from a Florida community. The National Cancer Institute Diet History Questionnaire was used. Plasma cobalamin, total transcobalamin, holo-transcobalamin, methylmalonic acid (MMA), total homocysteine (tHcy), and autoantibodies against intrinsic factor (IF) and Helicobacter pylori were analyzed in blood samples.

RESULTS

Antibodies to H. pylori were detected in 12% of subjects (35/299), and negative results for IF antibodies were obtained for all subjects. The intake of vitamin B-12 correlated significantly with cobalamin, holo-transcobalamin, MMA, and tHcy. Subjects were divided into quintiles on the basis of their dietary vitamin B-12 intake (range: 0.42-22.7 microg/d), and biomarkers of vitamin B-12 status were plotted against estimated dietary vitamin B-12 intake. All biomarkers appeared to level off at a daily dietary vitamin B-12 intake between 4.2 and 7.0 microg.

CONCLUSION

In persons with normal absorption, our data indicate that an intake of 4-7 microg vitamin B-12/d is associated with an adequate vitamin B-12 status, which suggests that the current RDA of 2.4 microg vitamin B-12/d might be inadequate for optimal biomarker status even in a healthy population between 18 and 50 y of age.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

Hypersegmented neutrophils and reversible hyperpigmentation in vitamin B(12) deficiency in Ghana

The present report concerns three cases of vitamin B(12) deficiency in Ghana. One case presented in the expected textbook manner with neurological signs, anaemia and a low serum vitamin B(12) level, whereas another presented with anaemia and hyperpigmentation, but a high serum vitamin B(12) level. Both responded well to treatment with vitamin B(12). It is suggested from the literature that the high serum vitamin B(12) may have been the result of high intrinsic factor antibodies. The third patient presented with haemolytic anaemia with depression, and was managed as such initially. She responded well, with a normalisation of haemoglobin levels. Persisting vague neurological symptoms lead to a check of serum vitamin B(12), which was found to be low. Her symptoms cleared with vitamin B(12) treatment. The need for a pragmatic approach in diagnosing vitamin B(12) deficiency is stressed.

The critical role of vitamin B12

Vitamin B12 affects the peripheral and central nervous systems, bone marrow, skin and mucous membranes, bones, and vessels, as well as the normal development of children. Although there is undoubtedly an association between vitamin B12 and homocysteinemia, their relative influence on cardiovascular events is controversial. Some large studies confirm that a supplementation with group B vitamins did not reduce the risk of major cardiovascular events or all-cause mortality in patients with vascular disease. The outcomes of these and similar trials could have been different had the researchers considered the following points: Using vitamin B12 or B-complex as secondary prevention of cardiovascular events for patients with irreversible changes of blood vessels is probably in error. Rather, vitamin B12 or B-complex should be used as primary prevention. Also, using high doses of vitamin B12 will probably be more effective than using low doses of "group B vitamins" The effect of vitamin B12 on the proliferation of malignant cells has been examined in vivo and in vitro in numerous studies. Their results indicate that methylcobalamin inhibits the proliferation of malignant cells and propose the possibility of methylcobalamin as a candidate of potentially useful agents for the treatment for some malignant tumors. There are many articles indicating the increasing prevalence of low vitamin B12 level in different segments of general population. In order to prevent serious health problems, vitamin B12 routine fortification should be seriously considered and discussed.

KEYWORDS

vitamin B12; homocysteine; malignancy; vitamin B12 routine fortification; recurrent aphthous stomatitis.

Aetiological factors and perception of anaemia in Tunisian women of reproductive age

Objectives

To identify aetiological factors in anaemia and to explore knowledge, perceptions and attitudes towards anaemia.

Design

Two cross-sectional surveys and sixteen focus group discussions.

Setting

The two regions with the highest prevalence of anaemia in Tunisia, Greater Tunis (GT) and the South West (SW).

Subjects

Two representative samples of 687 (GT) and 729 (SW) women of reproductive age; 108 women were included in focus group discussions.

Results

Among anaemic women, 63·4 % in the GT region and 80·2 % in the SW displayed iron deficiency (ID). Genetic haemoglobinopathies accounted for 10·0 % and 3·6 % of the cases of anaemia in the two regions, respectively. After adjustment for confounders, the major factors for iron-deficiency anaemia were low dietary Fe intake (OR = 5·0, 95 % CI 3·0, 8·4), drinking tea after eating (OR = 3·4, 95 % CI 2·0, 5·7) and pica (OR = 2·1, 95 % CI 1·1, 3·9). Most of the women related anaemia to the following causes: malnutrition, lack of hygiene, and their heavy workload and responsibilities in the household. Many women connected anaemia with hypotension. Few established a relationship between ID and anaemia. They had confidence in their doctor for treatment, but many complained they were not given sufficient information. Low dietary Fe intake, inappropriate food practices and inadequate perceptions contribute to the aetiology of anaemia in women.

Conclusions

These results point out to the need for a strategy combining food fortification, Fe supplementation for pregnant women, nutritional education for the general public and at-risk specific target groups, and training of health professionals.

A High Prevalence of Biochemical Evidence of Vitamin B12 or Folate Deficiency does not Translate into a Comparable Prevalence of Anemia

Based on biochemical evidence, a high prevalence of biochemical evidence of vitamin B12 or folate deficiency has been reported in a number of areas in the world. The evidence that these biochemical abnormalities lead to a comparable prevalence of anemia is reviewed. The overall contribution of vitamin B12 deficiency to the global burden of anemia is probably not significant, except perhaps in women and their infants and children in vegetarian communities. In developed countries, folate-deficiency anemia is uncommon. In some developing countries, this anemia is still seen, but there are no comprehensive data on the relative prevalence compared with anemia due to malaria, iron-deficiency, hemoglobinopathy, and HIV disease. It seems unlikely that folate deficiency makes a major contribution to the burden of anemia in developing countries. Iron-deficiency anemia may coexist with vitamin B12 and especially folate deficiency, and may confound the hematological features of the vitamin deficiencies whose prevalence would then be underestimated. Supplementation of the diet of pregnant women with folic acid can virtually eliminate folate-deficiency anemia in these women. There are very few data on the hematological effect of vitamin B12 supplementation or fortification at the population level. The addition of vitamin B12 to the supplementation of the diet of pregnant women with iron and folic acid does not produce an increased hematological response, at least in nonvegetarian populations. There are numerous reports of the effect of folic acid fortification of food on tests of folate status, but only a single published report on the hematological response was found.

Is folic acid good for everyone?

Fortification of food with folic acid to reduce the number of neural tube defects was introduced 10 y ago in North America. Many countries are considering whether to adopt this policy. When fortification is introduced, several hundred thousand people are exposed to an increased intake of folic acid for each neural tube defect pregnancy that is prevented. Are the benefits to the few outweighed by possible harm to some of the many exposed? In animals, a folic acid-rich diet can influence DNA and histone methylation, which leads to phenotypic changes in subsequent generations. In humans, increased folic acid intake leads to elevated blood concentrations of naturally occurring folates and of unmetabolized folic acid. High blood concentrations of folic acid may be related to decreased natural killer cell cytotoxicity, and high folate status may reduce the response to antifolate drugs used against malaria, rheumatoid arthritis, psoriasis, and cancer. In the elderly, a combination of high folate levels and low vitamin B-12 status may be associated with an increased risk of cognitive impairment and anemia and, in pregnant women, with an increased risk of insulin resistance and obesity in their children. Folate has a dual effect on cancer, protecting against cancer initiation but facilitating progression and growth of preneoplastic cells and subclinical cancers, which are common in the population. Thus, a high folic acid intake may be harmful for some people. Nations considering fortification should be cautious and stimulate further research to identify the effects, good and bad, caused by a high intake of folic acid from fortified food or dietary supplements. Only then can authorities develop the right strategies for the population as a whole.

Modern society and prospects of low vitamin B12 intake

BACKGROUND

Vitamin B(12) deficiency can occur in individuals with dietary patterns that exclude animal foods and patients who are unable to absorb vitamin B(12 )in food.

MATERIAL AND METHOD

Our clinic serves a high-income population living in Southern Israel. We hypothesize that a tendency to decrease of level of vitamin B(12) in our population is caused by a premeditated decrease in consumption of animal products. We analyzed 512 medical histories of patients undergoing blood tests for vitamin B(12) level for various reasons.

RESULT

The level of vitamin B(12) in 192 patients (37.5%) was less than 250 pg/ml.

CONCLUSION

As a result of media information disseminating the relationship between meat, cholesterol and cardiovascular diseases, consumption of meat, particularly beef, has decreased. Changes in life style among segments of the population with high socioeconomic level, on one hand, and the existence of poverty, on the other, are two main factors in the decreasing consumption of animal products. This causes a decrease in the level of vitamin B(12) in the general population, and as a consequence, this will increase pathology due to vitamin B(12) deficiency. In lieu of these possible developments and in order to prevent serious health problems, vitamin B(12) fortification should be seriously considered and discussed.

Nutritional neuropathies

Optimal functioning of the central and peripheral nervous system is dependent on appropriate nutrients. Neurologic consequences of nutritional deficiencies are not restricted to underdeveloped countries. Multiple nutritional deficiencies can coexist. Obesity is of particular concern in the developed world. The rising rate of bariatric surgery are accompanied by neurologic complications related to nutrient deficiencies. Prognosis depends on prompt recognition and institution of appropriate therapy. This review discusses peripheral nervous system manifestations related to the deficiency of key nutrients, neurologic complications associated with bariatric surgery, and conditions that have a geographic significance associated with bariatric surgery and certain conditions that have a geographic predilection.

Nutritional megaloblastic anemia in young Turkish children is associated with vitamin B-12 deficiency and psychomotor retardation

We aimed to investigate the presence of psychomotor retardation, physical and laboratory examination in infants with megaloblastic anemia. Inclusion criteria for the study were; age 9 to 36 months, refusal of food except for breast and cow milk, loss of appetite, developmental delay, significant pallor, and hypersegmentation neutrophils in the peripheral blood smear. A total of 33 children fulfilling the inclusion criteria were enrolled among 3368 patients attending Pediatric Outpatient Clinics of şirnak-Cizre State Hospital between January 25, 2004 and May 5, 2004. Mean age was 16.4 months. Thirty-two patients had Vitamin B12 deficiency, 1 patient had folate deficiency, and 10 patients had combined vitamin B12 and folate deficiency. Statistically, a positive significant relationship was detected between serum vitamin B12 levels and mean corpuscular volume (P = 0.001, r = 0.56), and between vitamin B12 levels and hemoglobin (P = 0.004, r = 0.49). We believe that preventative measures such as fortification of flour with vitamin B12, nutritional support with vitamin B12 for the mother during pregnancy and nursing, provision of adequate primary preventive health services, and starting complementary food after 6 months of age are important determinants for preventing megaloblastic anemia.

Pernicious anemia in Chinese: a study of 181 patients in a Hong Kong hospital

To study the clinical and hematologic features of pernicious anemia in Chinese, we describe 181 Chinese with megaloblastic anemia and low serum cobalamin, in association with either classic Schilling test results (82 patients) or the presence of serum antibody to intrinsic factor (99 patients), encountered in a regional hospital in Hong Kong from May 1994 to May 2005. The median age was 75 years (range, 32-95 yr) and the male to female ratio was 1:1.5. The chief presenting feature was anemia, and fewer than 10% of patients presented predominantly with neurologic deficit. Gastric biopsies of 109 patients showed glandular atrophy in 73, endocrine cell hyperplasia in 5, polyps in 14, adenocarcinoma in 1, and chronic gastritis in the rest. Gastric adenocarcinoma occurred in 1.7% of patients after a median follow-up of 35 months (range, 0.5-132 mo). Diabetes mellitus occurred in 24% of patients and thyroid disease in 7%. No specific ABO blood group was associated with pernicious anemia. Serum antibody to intrinsic factor (73%) occurred more frequently than serum antibody to gastric parietal cell (65%) (p=0.353). The frequency of serum antibody to gastric parietal cell was higher in male (78%) than in female patients (53%) (p=0.018). Pernicious anemia is a major cause of megaloblastic anemia in Chinese.

A daily intake of approximately 6 microg vitamin B-12 appears to saturate all the vitamin B-12-related variables in Danish postmenopausal women

BACKGROUND

Recommended daily intakes of vitamin B-12 vary between 2 and 6 microg.

OBJECTIVE

The objective was to examine the associations between vitamin B-12 intake and markers of vitamin B-12 deficiency.

DESIGN

We studied 98 Danish postmenopausal women aged 41-75 y. Serum cobalamin, transcobalamin (TC) saturated with vitamin B-12 (holo-TC), TC saturation (holo-TC/total TC), methylmalonic acid (MMA), and total homocysteine (tHcy) were measured to assess vitamin B-12 status. Dietary intakes of vitamin B-12 were determined from 7-d weighed food records. Gastric pH measurement and the alkali-challenge test were performed with the use of Heidelberg radiotelemetric capsules.

RESULTS

The total intake of vitamin B-12 ranged from 1.2 to 23.9 microg/d. All vitamin B-12-related variables, except gastric pH, correlated significantly with total vitamin B-12 intake. Those taking supplements (54%) had higher circulating concentrations of cobalamin and TC saturation and lower concentrations of MMA and tHcy than did those not taking supplements. All subjects were divided into quintiles according to their total vitamin B-12 intake. For all the variables analyzed, the curves appeared to level off at a daily vitamin B-12 intake of approximately 6 microg; the median (and 25th-75th percentiles) for cobalamin was 380 (270-480) pmol/L, for holo-TC was 119 (92-162) pmol/L, for MMA was 0.12 (0.14-0.17) micromol/L, and for tHcy was 9.75 (8.3-11.40) micromol/L (n = 58).

CONCLUSION

A daily vitamin B-12 intake of 6 microg appeared to be sufficient to correct all the vitamin B-12-related variables measured in the postmenopausal Danish women in this study.

Treatable factors associated with severe anaemia in adults admitted to medical wards in Blantyre, Malawi, an area of high HIV seroprevalence

Severe anaemia is a common presentation in non-pregnant adults admitted to hospital in southern Africa. Standard syndromic treatment based on data from the pre-HIV era is for iron deficiency, worms and malaria. We prospectively investigated 105 adults admitted consecutively to medical wards with haemoglobin < 7 g/dl. Those with acute blood loss were excluded. Patients were investigated for possible parasitic, bacterial, mycobacterial and nutritional causes of anaemia, including bone marrow aspiration, to identify potentially treatable causes. Seventy-nine per cent of patients were HIV-positive. One-third of patients had tuberculosis, which was diagnosed only by bone marrow culture in 8% of HIV-positive patients. In 21% of individuals bacteria were cultured, with non-typhi salmonella predominating and Streptococcus pneumoniae rare. Iron deficiency, hookworm infection and malaria were not common in HIV-positive anaemic adults, although heavy hookworm infections were found in 6 (27%) of the 22 HIV-negative anaemic adults. In conclusion, conventional treatment for severe anaemia in adults is not appropriate in an area of high HIV prevalence. Occult mycobacterial disease and bacteraemia are common, but iron deficiency is not common in HIV-positive patients. In addition to iron supplements, management of severe anaemia should include investigation for tuberculosis, and consideration of antibiotics active against enterobacteria.

Vitamin B12 deficiency as a worldwide problem

Pernicious anemia is a common cause of megaloblastic anemia throughout the world and especially in persons of European or African descent. Dietary deficiency of vitamin B12 due to vegetarianism is increasing and causes hyperhomocysteinemia. The breast-fed infant of a vitamin B12-deficient mother is at risk for severe developmental abnormalities, growth failure, and anemia. Elevated methylmalonic acid and/or total homocysteine are sensitive indicators of vitamin B12-deficient diets and correlate with clinical abnormalities. Dietary vitamin B12 deficiency is a severe problem in the Indian subcontinent, Mexico, Central and South America, and selected areas in Africa. Dietary vitamin B12 deficiency is not prevalent in Asia, except in vegetarians. Areas for research include intermittent vitamin B12 supplement dosing and better measurements of the bioavailability of B12 in fermented vegetarian foods and algae.

Population-based differences in frequency of the transcobalamin II Pro259Arg polymorphism

OBJECTIVE

A common polymorphism of the transcobalamin II (TC-II) gene, Pro250Arg, has been implicated as a possible genetic factor in population-based differences in vitamin B(12) metabolism. Our objective was to determine whether the prevalence of TC-II Pro259Arg polymorphism differs significantly between Caucasian, Asian and African-American groups.

METHODS

Genomic DNA was available on 187 Caucasians and 43 Asians from the Toronto area, and 51 African-Americans from Northeastern United States. A mutagenically separated PCR method was employed to genotype these groups for the TC-II Pro259Arg polymorphism (776C-->G).

RESULTS

The frequency of the Arg 259 allele varied significantly among the three groups studied (0.439 in Caucasian, 0.558 in Asian and 0.363 in African; P = 0.022). The Asian group had a significantly higher frequency of the Arg 259 allele compared to the Caucasian (P = 0.030) and the African-American group (P = 0.006). The frequency of the Arg 259 allele in the Caucasian and African-American groups was not significantly different (P = 0.103).

CONCLUSION

Population-based differences in TC-II Pro259Arg frequency are significant and could be a contributor to ethnic variation in susceptibility to vitamin B(12) deficiency, a common and persistent problem.

High prevalence of cobalamin deficiency in Guatemalan schoolchildren: associations with low plasma holotranscobalamin II and elevated serum methylmalonic acid and plasma homocysteine concentrations

BACKGROUND

Studies conducted in Guatemala, Mexico, and Venezuela have found high prevalences of low plasma cobalamin (vitamin B-12) concentrations in infants and children. It is not known whether these low cobalamin concentrations are accompanied by altered metabolic functions.

OBJECTIVE

We sought to assess the prevalence of cobalamin deficiency in Guatemalan children by using sensitive and specific markers of deficiency.

DESIGN

Children (n = 553) were screened for low plasma cobalamin. Those with low plasma cobalamin (< 162 pmol/L) were matched by age, grade, and sex to those with marginal (162-221 pmol/L) and adequate (> 221 pmol/L) concentrations. In this matched subset (n = 180), additional biochemical indicators of cobalamin deficiency were measured.

RESULTS

Of the 553 children screened, 11% had low plasma cobalamin and an additional 22% had marginal concentrations. The prevalences of elevated serum methylmalonic acid (MMA), plasma homocysteine, or both were significantly higher in children with low and marginal plasma cobalamin than in children with adequate plasma cobalamin. Mean serum MMA was high in all groups compared with values reported in other populations. Mean plasma holotranscobalamin II concentrations were significantly lower in children with low rather than marginal or adequate plasma cobalamin. However, holotranscobalamin II was a less sensitive indicator of cobalamin depletion than was MMA.

CONCLUSION

Biochemical markers of cobalamin deficiency confirmed that the cobalamin status of children with low and marginal plasma cobalamin is inadequate to support normal metabolic function.

Anaemia and micronutrient deficiencies

Anaemia in pregnancy is a common and worldwide problem that deserves more attention. For many developing countries, prevalence rates of up to 75% are reported. Anaemia is frequently severe in these situations and can be expected to contribute significantly to maternal mortality and morbidity. After a discussion of definitions, screening for anaemia and prevalence, the relationship between anaemia and maternal mortality and morbidity will be reviewed. Micronutrient deficiency and especially iron deficiency is believed to be the main underlying cause for anaemia. More recently the role of vitamin A deficiency as a contributing factor to anaemia has also been examined. The difficulties of assessment of micronutrient sufficiency or deficiency in pregnancy are described, as is the interaction between infection and micronutrient deficiency states.

Prevalence of iron deficiency with and without concurrent anemia in population groups with high prevalences of malaria and other infections: a study in Côte d'Ivoire

BACKGROUND

Iron deficiency is highly prevalent in most developing countries. However, its detection is often obscured by infections and inflammatory disorders that are common in the same populations.

OBJECTIVE

The aim of this study was to estimate the prevalence of iron deficiency with or without concurrent anemia in different population groups from Côte d'Ivoire and to evaluate the influence of infectious and inflammatory disorders on iron-status indexes.

DESIGN

Blood samples from 1573 children, women, and men were analyzed for hemoglobin, serum ferritin, zinc protoporphyrin, and serum transferrin receptor. C-reactive protein was used as the indicator of inflammation or infection, and samples were screened for malarial parasites and hemoglobinopathies. Iron deficiency was defined as 2 of 3 iron-status indexes outside the cutoff values, and iron deficiency anemia (IDA) was defined as iron deficiency with concurrent anemia. Pearson's correlation coefficients were used to evaluate the influence of malaria and inflammation on iron-status indexes.

RESULTS

The prevalence of iron deficiency was 41-63% in the women and children and 13% in the men, whereas the prevalence of IDA was 20-39% in the women and children and 4% in the men. The detection of iron deficiency and IDA was obscured by the high prevalence of inflammatory disorders.

CONCLUSIONS

Iron deficiency and IDA are highly prevalent in the women and children in Côte d'Ivoire. Iron deficiency was detected in approximately 50% of anemic women and children, which indicates that hemoglobin alone is not a good indicator of iron status when inflammatory disorders are highly prevalent. The serum transferrin receptor is the most useful single indicator of iron deficiency because it was the only iron-status index unaffected by malaria or inflammation.

Anemia

Anemia is an enormous problem worldwide that is worse in the developing countries but by no means lacking in developed countries. Women and children are disproportionately affected. Nutritional anemias, mainly caused by a lack of iron and folate, are largely correctable by dietary improvement, but this socioeconomic change may not be readily achieved. The inherited disorders, the hemoglobinopathies and thalassemias, in their heterozygous forms are beneficial to the affected populations. Prevention of the homozygous forms and the serious diseases that result can only be addressed by education. These conditions are seen in all types of medical practice ranging from neonatology to geriatrics and public health and are an ongoing concern to all physicians.

Etiology of anemia in pregnancy in south Malawi

BACKGROUND

Anemia in pregnancy is a major public health problem in developing countries. In sub-Saharan Africa, such anemia is generally accepted as resulting from nutritional deficiencies, particularly iron deficiency.

OBJECTIVE

We comprehensively assessed the full spectrum of nutritional and nonnutritional factors associated with pregnancy anemia.

DESIGN

Iron, folate, vitamin B-12, and vitamin A were measured in serum in a cross-sectional study of 150 pregnant women in Blantyre, Malawi. Bone marrow aspirates were evaluated, peripheral blood films were examined for malaria parasites, stool and urine samples were examined for helminthic infection, and tests were done for genetic disorders and for HIV infection. C-reactive protein (CRP) concentrations and erythrocyte sedimentation rates were measured as markers of inflammation.

RESULTS

Of the 150 anemic women, 23% were iron deficient with no evidence of folate, vitamin B-12, or vitamin A deficiencies; 32% were deficient in iron and one or more of the other micronutrients; 26% were not iron deficient but had evidence of one of the other micronutrient deficiencies, most often vitamin A; and 19% were not deficient in any of the micronutrients studied. CRP concentrations were notably high in 54% of the anemic women with no nutritional deficiencies and in 73.5% of the anemic women who were iron replete by bone marrow assessment.

CONCLUSION

The role of chronic inflammation as a possible contributing factor to anemia in pregnancy has important implications for the clinical evaluation and treatment of women.

Nutrition in pregnancy: mineral and vitamin supplements

Pregnancy is associated with physiologic changes that result in increased plasma volume and red blood cells and decreased concentrations of circulating nutrient-binding proteins and micronutrients. In many developing countries, these physiologic changes can be aggravated by undernutrition, leading to micronutrient deficiency states, such as anemia, that can have disastrous consequences for both mothers and newborn infants. Multiple micronutrients are often taken by pregnant women in developed countries, but their benefits are limited, except for prophylactic folic acid taken during the periconceptional period. Women in developing countries may benefit from multiple-micronutrient prophylaxis in pregnancy, but the underlying basis and rationale for changing from supplementation with iron and folate to supplementation with multiple micronutrients has not been debated in the context of existing program objectives. There is an urgent need for this discussion so that both program effectiveness and program efficacy can be improved.

Etiology and diagnostic evaluation of macrocytosis

BACKGROUND

Elevation of mean cell volume (MCV) is a common clinical problem, but the etiologic spectrum and optimal diagnostic evaluation of macrocytosis are not well defined.

METHODS

We studied 300 consecutive hospitalized adult patients with MCV values > or = 100 fL. Assessment included complete blood counts, morphologic review, liver function tests, and levels of serum cobalamin (Cbl), methylmalonic acid, and total homocysteine.

RESULTS

The most common cause of macrocytosis was drug therapy, followed by alcohol, liver disease, and reticulocytosis. Megaloblastic hematopoiesis accounted for less than 10% of cases. MCV values > 120 fL were usually caused by Cbl deficiency. Anisocytosis, macro-ovalocytosis, and teardrop erythrocytes were most prominent in megaloblastic hematopoiesis. Elevated levels of serum methylmalonic acid and total homocysteine were useful in the diagnosis of Cbl deficiency.

CONCLUSIONS

Drugs and alcohol are the most common causes of macrocytosis in hospitalized patients in a New York City teaching hospital. We have formulated tentative guidelines for the evaluation of high MCV values in this setting.

Plasma vitamin B-12 concentrations relate to intake source in the Framingham Offspring study

BACKGROUND

Low vitamin B-12 status is prevalent among the elderly, but few studies have examined the association between vitamin B-12 status and intake.

OBJECTIVE

We hypothesized that vitamin B-12 concentrations vary according to intake source.

DESIGN

Plasma concentrations and dietary intakes were assessed cross-sectionally for 2999 subjects in the Framingham Offspring Study. The prevalence of vitamin B-12 concentrations <148, 185, and 258 pmol/L was examined by age group (26-49, 50-64, and 65-83 y), supplement use, and the following food intake sources: fortified breakfast cereal, dairy products, and meat.

RESULTS

Thirty-nine percent of subjects had plasma vitamin B-12 concentrations <258 pmol/L, 17% had concentrations <185 pmol/L, and 9% had concentrations <148 pmol/L, with little difference between age groups. Supplement users were significantly less likely than non-supplement-users to have concentrations <185 pmol/L (8% compared with 20%, respectively). Among non-supplement-users, there were significant differences between those who consumed fortified cereal >4 times/wk (12%) and those who consumed no fortified cereal (23%) and between those in the highest and those in the lowest tertile of dairy intake (13% compared with 24%, respectively), but no significant differences by meat tertile. Regression of plasma vitamin B-12 on log of intake, by source, yielded significant slopes for each contributor adjusted for the others. For the total group, b = 40.6 for vitamin B-12 from vitamin supplements. Among non-supplement-users, b = 56.4 for dairy products, 35.2 for cereal, and 16.7 for meat. Only the meat slope differed significantly from the others.

CONCLUSIONS

In contrast with previous reports, plasma vitamin B-12 concentrations were associated with vitamin B-12 intake. Use of supplements, fortified cereal, and milk appears to protect against lower concentrations. Further research is needed to investigate possible differences in bioavailability.

Racial differences in prevalence of cobalamin and folate deficiencies in disabled elderly women

BACKGROUND

Many previous investigations of cobalamin and folate status were performed in white populations.

OBJECTIVE

Our objective was to determine whether there are racial differences in the prevalence of cobalamin and folate deficiency.

DESIGN

The study was a cross-sectional comparison of baseline serum cobalamin, folate, methylmalonic acid (MMA), total homocysteine (tHcy), and creatinine concentrations, complete blood count, and vitamin supplementation in 550 white and 212 African American subjects from a cohort of physically disabled older women.

RESULTS

The mean (+/-SD) serum MMA concentration was significantly higher in whites than in African Americans: 284 +/- 229 compared with 218 +/- 158 nmol/L (P = 0.0001). tHcy concentration was higher in African Americans than in whites: 12.4 +/- 7.0 compared with 10.9 +/- 4.6 micromol/L (P = 0.001). Serum cobalamin was lower in whites (P = 0.0002). Cobalamin deficiency (serum cobalamin <258 pmol/L and MMA >271 nmol/L) was more frequent in the white women (19% compared with 8%; P < 0.0003). Folate deficiency (serum folate <11.4 nmol/L, tHcy >13.9 micromol/L, and MMA <271 nmol/L) was more prevalent in African Americans than in whites (5% compared with 2%; P = 0.01). Multivitamin use was associated with lower tHcy but not with MMA concentrations. Regression models showed that age >85 y, African American race, serum creatinine >90 micromol/L, and high MMA concentration were all significantly correlated with higher tHcy. Creatinine > 90 micromol/L, white race, and folate concentration were positively associated with MMA concentration.

CONCLUSIONS

Cobalamin deficiency with elevated serum MMA concentration is more prevalent in elderly white than in African American women and elevated serum tHcy and folate deficiency are more prevalent in elderly African American than in white women.

Pancytopenia in Zimbabwe

BACKGROUND

There has been little systematic study of the clinical spectrum of pancytopenia, and the optimal diagnostic approach to pancytopenia remains undefined.

METHODS

The authors studied 134 hospitalized pancytopenic patients in Zimbabwe in both consecutive and nonconsecutive fashion.

RESULTS

The most common cause of pancytopenia was megaloblastic anemia, followed by aplastic anemia, acute leukemia, acquired immunodeficiency syndrome (AIDS), and hypersplenism. Severe pancytopenia was usually due to aplastic anemia. Patients with aplastic anemia and acute leukemia were usually children, whereas those with megaloblastic anemia were adults. Moderate to severe anemia was noted throughout the series, but was most striking in patients with megaloblastic anemia, aplastic anemia, and acute leukemia. The mean corpuscular volume (MCV) was elevated in most patients with megaloblastic hematopoiesis, aplastic anemia, and acute nonlymphocytic leukemia. Normal or low MCV values were noted in almost one third of patients with megaloblastic anemia. Anisocytosis, poikilocytosis, macroovalocytosis, microcytosis, fragmentation, and teardrop erythrocytes were more prominent on the blood films of patients with megaloblastic anemia.

CONCLUSIONS

Megaloblastic anemia, aplastic anemia, and AIDS are the most common causes of pancytopenia in Zimbabwe. Aplasia is the most frequent cause of severe pancytopenia. The authors have formulated tentative guidelines for the evaluation of pancytopenic patients in this setting.

Vitamin B12 levels in pregnancy influence erythropoietin response to anemia

OBJECTIVE

to discover whether vitamin B12 levels influence erythropoietin (EPO) response during pregnancy.

STUDY DESIGN

117 pregnant women after the 27th week were divided into three groups according to log vitamin B12 concentrations. EPO (by enzyme-linked immunosorbent assay), Hemoglobin (Hb) and medium corpuscular Hb concentration (MCHC) were measured in these patients. The tests used were: calculation of simple statistic, regression coefficient and t-independent test with level of significance. An exclusive partitioned cluster method (K-means procedure) was used.

RESULTS

For the lowest vitamin B12 levels there is an unexpected lack of difference in plasma EPO levels between anemic and nonanemic patients. In fact EPO levels were high even in nonanemic women. The only parameter of the blood count that seems to change in relation to vitamin B12 concentration is the MCHC.

CONCLUSIONS

These results suggest that low vitamin B12 levels inhibit the suppression of EPO response in nonanemic pregnant women probably through MCHC modifications.

Neurological complications of acquired cobalamin deficiency: clinical aspects

Neuropsychiatric syndromes occur in about 40% of Cbl-deficient patients and are characterized by progressive and variable damage to the spinal cord, peripheral nerves and cerebrum. The first abnormality is usually sensory impairment, most often presenting as distal and symmetrical paraesthesiae of the lower limbs and frequently associated with ataxia. Almost all patients demonstrate loss of vibratory sensation, often in association with diminished proprioception and cutaneous sensation and a Romberg sign. Corticospinal tract involvement is common in more advanced cases, with abnormal reflexes, motor impairment and, ultimately, spastic paraparesis. A minority of patients exhibit mental or psychiatric disturbances or autonomic signs, but these rarely if ever occur in the absence of other neurological changes. Because N2O inactivates Cbl, abuse of the gas may lead to typical Cbl neuropathy. Haematological changes are minimal and serum Cbl levels and Schilling tests normal in most patients. The severity of neurological abnormalities prior to treatment correlates with the duration of symptoms and the haemoglobin level. Initial severity, symptom duration and initial haemoglobin also correlate with residual neurological damage after Cbl therapy. The inverse correlation between severity of anaemia and neurological damage is not understood. Diagnosis of Cbl neuropathy can usually be made in the presence of the typical neuropsychiatric abnormalities, a low serum Cbl level and evidence of megaloblastic haemopoiesis. In some patients serum MMA and HCYS determinations or a therapeutic trial may be required. A neurological response usually occurs within the first 3 months, although further improvement may occur with time. Patients with advanced disease may be left with major residual disability. Therefore early diagnosis is critical. Pharmacological doses of folic acid reverse the haematological abnormalities of Cbl deficiency. This may allow neuropathy to develop or progress and make recognition of deficiency more difficult. There is no clear evidence that folic acid therapy precipitates or exacerbates Cbl neuropathy. Haematological improvement may occur in a fraction of patients receiving small doses of folate, but the data are inadequate to predict the danger of low levels of folate supplementation in the general population.

Metabolite assays in cobalamin and folate deficiency

Cbl and folate are both necessary for the metabolism of HCYS, whereas only Cbl is required for MMA metabolism. During the past decade, analytical methods have been developed that are sensitive enough to detect low levels of MMA and HCYS normally present in the plasma. These methods are sufficiently precise to be used in the clinical laboratory and measurements of the serum levels of the metabolites provide sensitive and specific techniques for the identification of Cbl and folate deficiencies. These techniques constitute an important addition to the battery of diagnostic tests that are available for detecting the vitamin deficiencies and for distinguishing each from the other. By virtue of the role of Cbl and folate in the metabolic pathways that involve MMA and HCYS, levels of both metabolites rise in Cbl deficiency, but only HCYS rises in folate deficiency. During the development of Cbl or folate deficiencies, accumulation of these metabolites in the plasma signals the existence of a condition of biochemical vitamin deficiency of sufficient degree to cause impairment in the metabolic pathways which are dependent on these vitamins. Circulating metabolite levels appear to accurately reflect the nutritional status of the vitamins and a rise in serum metabolite levels is therefore one of the earliest and most reliable indicators of developing Cbl and folate deficiencies. Elevations of serum metabolites above the reference range not only precede a fall in the serum vitamin levels but also show a more consistent correlation with objective evidence of vitamin deficiency than do low blood vitamin levels. The advent of serum metabolite measurements has also made it possible to identify subtle or atypical forms of vitamin deficiency that may be associated with unusual or previously undiscovered disease manifestations. Thus, in patients who display only neurological manifestations of disease, underlying Cbl deficiency may be revealed by the finding of raised serum or urine levels of MMA. Similarly, unsuspected folate deficiency may be disclosed by the finding of a raised serum HCYS. This may have important implications with respect to disease risk, since there is mounting evidence that sub-optimal folate nutritional status may be associated with increased risks of vascular disease, neoplasia and birth defects. Finally, the measurement of serum levels of MMA, HCYS and other metabolites that accumulate in Cbl and folate deficiencies may provide important new insights into the mechanism whereby these vitamin deficiencies lead to different patterns and manifestations of disease.