High prevalence of low serum vitamin B12 in a multi-ethnic Israeli population

This study ascertained serum vitamin B12 levels among patients with Gaucher disease and among healthy Israelis. Serum B12 and metabolites' levels were studied in consecutive adult patients with Gaucher disease not treated with enzyme plus Ashkenazi Jewish neighbour-controls, together with healthy blood-donor volunteers of various ethnicities. Each group showed a high incidence of low serum B12 concentrations, with a 22.3% incidence among Ashkenazi Jews and 40% among patients with Gaucher disease. These findings raise questions on the individual and community levels of serum B12. We recommend evaluation of B12 levels among geographically contingent peoples.     

Severe megaloblastic bone marrow change associated with unsuspected mild vitamin B12 deficiency

Summary Two patients are reported who developed peripheral blood abnormalities and marked megaloblastic bone marrow change within eleven days of cardiac bypass surgery. The patients were shown to have unsuspected mild vitamin B₁₂ deficiency due to Addisonian pernicious anaemia. The megaloblastic changes were presumed to be precipitated by the increased demand for erythrocytes and platelets after surgery.     

Cobalamin deficiency with megaloblastic anaemia in one patient under long-term omeprazole therapy

The first case of cobalamin deficiency with megaloblastic anaemia in a patient under long-term omeprazole therapy is presented. This patient received omeprazole at a daily dose of 40–60 mg for 4 years as treatment for a gastro-oesophagal reflux complicated by peptic oesophagitis. Seric vitamin B12 was dramatically decreased at 80 pmol L^-1. The Schilling test was normal (13%) with crystalline [⁵⁷Co] cobalamin and it was at 0% with [⁵⁷Co] cobalamin-labelled trout meat. All other assimilation tests were normal except an expiratory hydrogen breath test performed with lactulose. The haematological status was restored after intramuscular treatment with cobalamin. In conclusion, prolonged omeprazole therapy can be responsible for a cobalamin deficiency due to protein-bound cobalamin malabsorption.     

High prevalences of vitamin B12 and folic acid deficiency in elderly subjects in Israel

The prevalences of vitamin B12 and folic acid deficiency in the general Israeli population of elders has not been assessed. We measured plasma cobalamin and folic acid concentrations in 418 subjects from four institutions for the aged, 749 subjects attending 19 geriatric day centres and 104 healthy controls. Methylmalonic acid (MMA) and/or homocysteine concentrations were determined in subjects who had a cobalamin concentration <221 pmol/l or folic acid concentration <11 nmol/l respectively. The prevalences of vitamin B12 deficiency (cobalamin <147 pmol/l and MMA > or =0.24 micromol/l), and folic acid deficiency (folic acid <11 nmol/l and homocysteine of >15 micromol/l) in subjects from day centres were 12.6% and 16.4% respectively, and in subjects from institutions 1.2% and 2.2% respectively (P < 0.001). Multiple logistic regression analysis indicated that the relative risk of living at home versus institutions for the aged was highly significant, with odds ratios (OR) of 6.8 [95% confidence interval (CI) 2.6-18.0] for vitamin B12 deficiency and 6.6 (95% CI 2.9-13.1) for folic acid deficiency. Analysis of data for day centre patients showed that folic acid deficiency was a significant risk factor of vitamin B12 deficiency (adjusted OR 3.68, 95% CI 2.27-5.98), and vitamin B12 deficiency was a significant risk of folic acid deficiency (adjusted OR 3.69, 95% CI 2.27-6.01). These data suggest that malnutrition is a major cause of the highly prevalent deficiencies of vitamin B12 and/or folic acid in elderly Israeli subjects dwelling at home.     

巨幼细胞性贫血患者骨髓检查结果分析

目的：了解巨幼细胞性贫血患者骨髓及实验室检查结果。方法：对222例巨幼细胞性贫血患者的骨髓象及血液的红细胞、白细胞、血小板和血清叶酸、维生素B12等结果进行总结分析。结果：有129例（58.1%）表现为全血细胞减少,以叶酸缺乏为主185例（83.3%）。叶酸、维生素B12缺乏越严重,骨髓中巨变等病态造血越明显。结论：巨幼细胞性贫血患者骨髓造血病态的程度往往反映患者营养不良的程度。     

Clinicopathological features of megaloblastic anaemia in Hong Kong: a study of 84 Chinese patients

Megaloblastic anaemia is uncommon in Hong Kong. Eighty-four consecutive Chinese patients with megaloblastic anaemia were studied. There were 48 males and 36 females, with a median age at presentation of 67 years. Vitamin B12 deficiency was found in all cases, with none of the patients showing folate deficiency. The frequency of pernicious anaemia in our patients was higher than in other south-east Asian series but comparable with western ones. When compared with patients in the West, our cases showed the following main differences: virtual absence of folate deficiency, even in alcoholics; absence of associated gastric malignancies; and a high frequency of tuberculosis.     

Correction of the DNA synthesis defect in vitamin B12 deficiency by tetrahydrofolate: evidence in favour of the methyl-folate trap hypothesis as the cause of megaloblastic anaemia in vitamin B12 deficiency

Summary. The critical disturbance of folate metabolism caused by vitamin B₁₂ deficiency which results in megalo- blastic anaemia remains controversial. Vitamin B₁₂ is required in the methionine synthase reaction in which homocysteine is converted to methionine and methyl tetrahydrofolate (methyl THF) to THF. The 'methyl-folate trap'hypothesis suggested that failure of demethylation of methyl THF with consequent deficiency of folate co-enzymes derived from THF is the crucial lesion caused by vitamin B₁₂ deficiency. A more recent theory suggested that reduced supply of methionine leads to reduced availability of 'activated formate'and hence of formyl THF and it is this defect that results in failure of folate co-enzyme synthesis. The present results, based on deoxyuridine suppression tests on 103 cases of megaloblastic anaemia, show that THF itself is equally capable of correcting the failure of thymidylate synthesis in vitamin B₁₂ deficiency as in folate deficiency. Although not as effective as formyl THF in correcting the dU blocking test in vitamin B₁₂ deficiency, this is equally so for the correction of the test by THF compared with formyl THF in folate deficiency. The results therefore favour the theory that it is in the supply of THF and not of 'active formate'or formyl THF that vitamin B₁₂ plays a critical role in folate metabolism.     

Serum methylmalonic acid and total homocysteine in patients with suspected cobalamin deficiency: A clinical study based on gastrointestinal histopathological findings

We compared the sensitivity and specificity of the two metabolite tests, methylmalonic acid (MMA) and total homocysteine (Hcy) in serum, and serum cobalamin (Cbl) in patients referred to our hospital because of suspected cobalamin deficiency and a serum cobalamin value at the referring unit <200 pmol/L. All 111 patients included were investigated using upper gastrointestinal endoscopy with biopsy specimens taken from the gastric and duodenal mucosa to find a morphological basis for cobalamin malabsorption as well as the Schilling test for the validation of the serum tests. All patients were treated with cobalamin and new blood samples were taken after 4 weeks. We found no difference in sensitivity and specificity between serum MMA, Hcy, and Cbl in identifying patients with and without conditions compatible with cobalamin malabsorption. Elevated serum MMA and Hcy were also found in about 15% of the group of patients with normal Schilling tests and without a morphological basis for cobalamin malabsorption. Moreover, most patients in this group responded with decreased values of the metabolite tests following cobalamin treatment, suggesting that neither elevated metabolites nor a decrease in these values following cobalamin treatment are specific for cobalamin deficiency. Am. J. Hematol. 56:230–238, 1997. © 1997 Wiley-Liss, Inc.     

Cobalamin Forms in Plasma and Tissue during Treatment of Vitamin B12 Deficiency

Thin-layer chromatography and bioautography were used to study the cobalamin pattern of plasma, erythrocytes, and hepatic tissue from patients with cobalamin deficiency on maintenance therapy with hydroxocobalamin (Vibeden®), a cyanocobalamin depot preparation (Betolvex®), or cyanocobalamin tablets (Behepan®). The cobalamin pattern in plasma is dominated by the form in which it is administered. The results of assaying the erythrocytes and liver biopsies show that the cobalamins administered are converted to the coenzyme forms in vivo, irrespective of the type of cobalamin preparation.     

Steroid-responsive functional B12 deficiency in association with transcobalamin II polymorphism 776C --> G

We present a case of intracellular vitamin B12 deficiency presenting with confusion, subacute combined degeneration of the cord, megaloblastic anaemia and intrinsic factor antibodies in the serum. Diagnosis was delayed by a normal serum B12 level and was confirmed by a grossly elevated serum homocysteine. There was a dramatic response to steroids. The patient was heterozygous for the transcobalamin (TC) II polymorphism 776C --> G. This case demonstrates the importance of functional assessment of intracellular B12 activity (e.g. serum homocysteine) in excluding B12 deficiency, the role of steroids in pernicious anaemia and a possible clinical correlation of a TCII polymorphism.     

The deoxyuridine suppression test performed on phytohaemagglutinin-stimulated peripheral blood cells fails to reflect in vivo vitamin B12 or folate deficiency

Because phytohaemagglutinin-stimulated lymphocytes acquire folate deficiency in vitro, we have re-examined the claim that the deoxyuridine suppression test (dU-test) based on such cells helps to diagnose megaloblastic states. dU-test results were obtained from the phytohaemagglutinin-stimulated blood cells of 77 patients at 6 concentrations of dU. 21 megaloblastic patients with cobalamin or folate deficiency did not have a mean blood dU-test result significantly higher than that of 21 normoblastic patients at any concentration of dU. Among all patients, however, there was a weak correlation between the blood and marrow dU-test results. Folic acid corrected the blood dU-test results more in the normoblastic than the megaloblastic patients, and a difference between the two groups appeared, but a large overlap persisted. Blood dU-test results tend to be higher in megaloblastic patients, but acquired folate deficiency obscures the distinction from normoblastic patients so that the test is not of diagnostic value.     

Schilling and protein-bound cobalamin absorption tests are poor instruments for diagnosing cobalamin malabsorption

Abstract. Lindgren A, Bagge E, Cederblad A, Nilsson 0, Persson H, Kilander AF (Boris Central Hospital, Sahlgrenska University Hospital, and Molndal Hospital, Sweden). Schilling and protein-bound cobalamin absorption tests are poor instruments for diagnosing cobalamin malabsorption. Objectives: To assess the advantage of a protein-bound cobalamin absorption test (PBAT) over the Schilling test in patients with suspeded cobalamin (vitamin B12) malabsorption. Design: Clinical study of consecutive patients referred from primary care units, medical and neurological clinics. Setting: The catchment area of Sahlgrenska University Hospital, Goteborg. Subjects. Referred patients (n = 155) with suspected cobalamin deficiency and at least one serum cobalamin value < 200 pmol L-l. Interventions: All patients were investigated with upper gastrointestinal endoscopy with biopsies taken upper gastrointestinal endoscopy with biopsies taken methylmalonic acid (h4MA) and homocysteine (Hcy) were determined in all 109 patients not on cobalamin substitution. A dual isotope cobalamin absorption test was then performed with the concomitant administration of crystalline (Schilling) and proteinbound cobalamin (PBAT). Main outcome measures: Number of patients with gastric body atrophy diagnosed with each absorption gastric body atrophy diagnosed with each absorption test and the relation between these results and functional cobalamin deficiency defined as elevated MMA and Hcy, that normalized after cobalamin substitution treatment. Results: The majority of patients with abnormal absorption tests had already developed elevated MMA and/or Hcy. PBAT was more sensitive than the Schilling test in identifyiog patients with gastric body atrophy but the sensitivity was too low for clinical use. About f of the patients with gastric body atrophy and normal absorption tests had already developed elevated MMA and/or Hcy. PBAT was more sensitive than the Schilling test in identifyiog patients with gastric body atrophy but the sensitivity was too low for clinical use. About f of the patients with gastric body atrophy and normal absorption tests had elevated MMA and/or Hcy, indicating cobalamin deficiency. Conclusion: PBAT may be somewhat more sensitive than the Schilling test but neither test is sensitive enough for diagnosing cobalamin malabsorption at an early stage.     

The marker of cobalamin deficiency, plasma methylmalonic acid, correlates to plasma creatinine

OBJECTIVE: To examine the relationship between the two diagnostic tests, plasma methylmalonic acid and plasma cobalamins, and their association with plasma creatinine, age and sex. DESIGN: Cross-sectional study of simultaneous laboratory measurements. SETTING: County of Aarhus, Denmark. SUBJECTS: Records on 1689 patients who had their first plasma methylmalonic acid measurement during 1995 and 1996, and who had a simultaneous measurement of plasma cobalamins. Plasma creatinine values measured within a week of measurements of plasma methylmalonic acid and plasma cobalamins were available for 1255 of the patients. MAIN OUTCOME MEASURES: Predictors of variation in plasma methylmalonic acid; plasma cobalamins, plasma creatinine, age and sex. RESULTS: Plasma methylmalonic acid was positively correlated with plasma creatinine, even for plasma creatinine within the normal range. These associations remained in a multiple regression analysis. For plasma cobalamins below 200 pmol L-1, there was a strong negative correlation between plasma methylmalonic acid and plasma cobalamins, whilst the association was weak for higher plasma cobalamin levels. Plasma methylmalonic acid increased and plasma cobalamins decreased with age. CONCLUSIONS: The strong correlation between plasma methylmalonic acid and plasma creatinine suggests that plasma creatinine - also within the normal range - must be taken into consideration when interpreting plasma methylmalonic acid.     

Elevated serum homocysteine as a predictor for vitamin B12 or folate deficiency

Abstract: Tissue deficiency of vitamin B₁₂ and folate results in an increase in serum homocysteine (sHcy). We have measured sHcy in patients with reduced serum vitamin B₁₂ and/or red cell folate (RCF) to determine its usefulness as a discriminant for the diagnostic interpretation of reduced vitamin levels. Of 3846 patients who had serum vitamin B₁₂ and RCF assayed, 335 (9%) had reduced vitamin levels. Multivariate analysis showed a significant association between sHcy and serum creatinine (p = 0.0001), positive intrinsic factor (IF) antibody or neutrophil hypersegmentation (NHS) (p = 0.001), increased MCV (p = 0.014) and low RCF (p = 0.025) but no relationship with the level of serum vitamin B₁₂ or haemoglobin. After censoring the patients with renal impairment (n = 54), the distribution of the remaining 72 patients with elevated sHcy was 37/151 (25%) with low serum vitamin B₁₂ with or without low RCF and 35/130 (27%) with low RCF alone. sHcy correctly identified response to vitamin therapy in 33/35 (94%) patients who had adequate parameters to assess response. The positive predictive values of IF antibody/NHS, macrocytosis and/or low RCF for elevated sHcy were 100% and 34% respectively. Twenty-four percent of patients with a low serum vitamin B₁₂ and elevated sHcy had no abnormal haematologic parameters as determined by the routine laboratory staff. These data suggest that the usefulness of measuring sHcy in a routine diagnostic setting is limited and a careful review of the peripheral blood for macrocytosis and NHS plus determination of RCF may be a more cost-effective process than sHcy assay in most instances to determine the presence of tissue deficiency.     

Discovery of vitamin B12 in the liver and its absorption factor in the stomach: a historical review

This review describes the early chronological events in the pursuit of a treatment for pernicious anaemia, and the subsequent discovery of vitamin B12 and the intrinsic factor. It details Castle's experiments which established the theory of extrinsic and intrinsic factors as hemopoietic principles, and describes the studies on purification of the anti-pernicious anaemia principle from liver tissue that terminated in the crystallization of vitamin B12 and identification of its coenzyme forms. Biochemical purification and characterization of the intrinsic factor secreted by the gastric parietal cells, and two other vitamin B12 proteins, R-binder (transcobalamin I, haptocorrin), and transcobalamin II, are discussed in detail. The biochemical reactions in micro-organisms and humans in which vitamin B12 is involved are then briefly reviewed, and finally and briefly the immunological basis of pernicious anaemia is discussed.     

Interrelationships between Vitamin B12 and Folic Acid in Myelomatosis: Cobalamin Coenzyme and Tetrahydrofolic Acid Function

Cobalamin and folate metabolism was investigated in 43 patients with myelomatosis, in 8 control subjects of similar age and 22 younger controls. Plasma total cobalamin was lower in myeloma patients than in either of the control groups and methylcobalamin (Me-Cbl) was disproportionately reduced. Erythrocyte levels of total cobalamin were very similar in patients and elderly controls but were half the levels in younger controls. Erythrocyte levels of Me-Cbl were slightly higher in patients than in the elderly controls. FIGLU excretion after L-histidine was elevated in 53 % of the patients but values did not correlate with serum or erythrocyte folate or with plasma total cobalamin. FIGLU excretion decreased after DL-methionine or Me-Cbl only in patients whose FIGLU excretion was initially high. The results are discussed in the light of the ‘methylfolate trap hypothesis’ and suggest that some patients with myelomatosis have insufficient activity of methionine synthetase to meet the additional metabolic demand for one carbon compounds.     

Acquired and inherited disorders of cobalamin and folate in children

Cobalamin deficiency in the newborn usually results from cobalamin deficiency in the mother. Megaloblastic anaemia, pancytopenia and failure to thrive can be present, accompanied by neurological deficits if the diagnosis is delayed. Most cases of spina bifida and other neural tube defects result from maternal folate and/or cobalamin insufficiency in the periconceptual period. Polymorphisms in a number of genes involved in folate and cobalamin metabolism exacerbate the risk. Inborn errors of cobalamin metabolism affect its absorption, (intrinsic factor deficiency, Imerslund‐Gräsbeck syndrome) and transport (transcobalamin deficiency) as well as its intracellular metabolism affecting adenosylcobalamin synthesis (cblA and cblB), methionine synthase function (cblE and cblG) or both (cblC, cblD and cblF). Inborn errors of folate metabolism include congenital folate malabsorption, severe methylenetetrahydrofolate reductase deficiency and formiminotransferase deficiency. The identification of disease‐causing mutations in specific genes has improved our ability to diagnose many of these conditions, both before and after birth.     

Glycosylated haemoglobin (HbA1c) in iron- and vitamin B12 deficiency

Glycosylated haemoglobin (HbA1c) was measured in 10 patients with iron deficiency anaemia, 10 patients with vitamin B12 deficiency anaemia and 10 healthy controls. Initially there were no significant differences between the groups (P greater than 0.4), but after treatment with iron and vitamin B12 for 3 and 6 weeks, the glycosylated haemoglobin concentration decreased significantly (P less than 0.01). It was concluded that glycosylated haemoglobin is a sensitive marker of the changes in the erythrocyte population that are observed when predominantly immature erythrocytes are being produced.     

Folate Concentration in Top,Middle and Bottom Layer of Packed Red Cells in Patients with Vitamin B12 Deficiency: Relation to Treatment

In response to specific treatment of vitamin B₁₂ deficient, anaemic patients there is an influx of folate into the young, circulating red cells. To separate new and old cells, capillary tubes filled with whole blood were centrifuged and the packed red cell column divided into top (T), middle (M) and bottom (B) layer. The newest cells are found in the T layer. The increase in red cell folate (RCF) concentration starts before, during or after the reticulocyte response, and is therefore not directly related to folate metabolism in the red precursor cells in the marrow. The low RCF concentration at the peak of the reticulocyte response in some of the cases demonstrates that the folate material, which may have been accumulated in the red precursor cells in the marrow, may be lost by the time the red cells enter the peripheral blood. The influx of folate into the young, circulating red cells is rapidly followed by an efflux of folate, suggesting that much of the folate material is still in the monoglutamate form. A new influx of folate is noted after a time lapse of from 5 to 10 d. Iron deficiency seems to prevent the uptake of folate by the circulating red cells.     

Vitamin B-12 treatment has limited effect on health-related quality of life among individuals with elevated plasma methylmalonic acid: a randomized placebo-controlled study

OBJECTIVE: To examine the hypothesis that treatment with vitamin B-12 improves health-related quality of life (HRQOL) in individuals with biochemical signs of vitamin B-12 deficiency. DESIGN: A randomized placebo-controlled study. SETTING: Municipality of Aarhus, Denmark. SUBJECTS: Nonhospitalized individuals (n = 140) with a modest increase in plasma methylmalonic acid (0.40-2.00 micromol L-1) not previously treated with vitamin B-12. INTERVENTION: The participants were randomized to vitamin B-12 injection treatment or placebo weekly for 4 weeks and re-examined 3 months later. The investigator and the participants were blinded to the intervention. MAIN OUTCOME MEASURE: Change in HRQOL assessed by the SF-36 questionnaire from baseline to follow-up examination 3 months later. RESULTS: The participants reported a significantly worser HRQOL than the age- and sex-matched Danish general population (P < 0.001). However, no change was observed after treatment with vitamin B-12 for seven of eight health dimensions. A significant improvement was found only in general health when compared with the placebo group (P = 0.03). CONCLUSIONS: Vitamin B-12 treatment influenced only one of eight dimensions of HRQOL amongst participants with biochemical signs of vitamin B-12 deficiency. We therefore question the benefit of vitamin B-12 treatment amongst elderly with a modestly increased plasma methylmalonic acid as the only sign of vitamin B-12 deficiency.