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Ralph Green - One of the best experts on this subject based on the ideXlab platform.
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Measurement of Total Vitamin B12 and Holotranscobalamin, Singly and in Combination, in Screening for Metabolic Vitamin B12 Deficiency
2015Co-Authors: Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:Background: The standard screening test for Vitamin B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both mea-sures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age>60 years). Plasma methylma-lonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 (<148 pmol/L) and low holoTC (<35 pmol/L) were observed in 6.5 % and 8.0%
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Measurement of Total Vitamin B12 and Holotranscobalamin, Singly and in Combination, in Screening for Metabolic Vitamin B12 Deficiency
2015Co-Authors: Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both mea-sures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age>60 years). Plasma methylma-lonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 (<148 pmol/L) and low holoTC (<35 pmol/L) were observed in 6.5 % and 8.0%, and increased methylmalonic acid (>350 nmol/L) an
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measurement of total Vitamin B12 and holotranscobalamin singly and in combination in screening for metabolic Vitamin B12 Deficiency
Clinical Chemistry, 2006Co-Authors: Joshua W Miller, Marjorie G Garrod, Alan L Rockwood, Mark M Kushnir, Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:Background: The standard screening test for Vitamin B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both measures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age ≥60 years). Plasma methylmalonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 ( 350 nmol/L) and homocysteine (>13 μmol/L) were observed in 12.1% and 17.0% of the study participants. In multiple regression models, holoTC explained 5%–6% more of the observed variance in methylmalonic acid and homocysteine than did total Vitamin B12 ( P ≤0.004). ROC curve analysis indicated that total Vitamin B12 and holoTC were essentially equivalent in their ability to discriminate persons with and without Vitamin B12 Deficiency. Individuals with low concentrations of both total Vitamin B12 and holoTC had significantly higher concentrations of methylmalonic acid and homocysteine than did individuals with total Vitamin B12 and/or holoTC within the reference intervals ( P <0.001). Conclusions: HoloTC and total Vitamin B12 have equal diagnostic accuracy in screening for metabolic Vitamin B12 Deficiency. Measurement of both holoTC and total Vitamin B12 provides a better screen for Vitamin B12 Deficiency than either assay alone.
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Vitamin B12 Deficiency is the dominant nutritional cause of hyperhomocysteinemia in a folic acid fortified population
Clinical Chemistry and Laboratory Medicine, 2005Co-Authors: Ralph Green, Joshua W MillerAbstract:Prevalence rates for folate Deficiency and hyperhomocysteinemia have been markedly reduced following the introduction of folic acid fortification in the United States. We report the prevalence of hyperhomocysteinemia in a population of community-dwelling elderly Latinos in the post-folic acid fortification era. We measured homocysteine, total Vitamin B12, holotranscobalamin, red blood cell folate, and serum creatinine in 1096 subjects aged > or =60 years. Hyperhomocysteinemia (>13 micromol/L) was observed in 16.5% of the subjects. The population attributable risk percentages for hyperhomocysteinemia were 29.7% for total B12 115 micromol/L. In contrast, the population attributable risk percentage for hyperhomocysteinemia was only 0.3% for red blood cell folate <365 nmol/L. We conclude that in the post-folic acid fortification era, low Vitamin B12 status has become the dominant nutritional determinant of hyperhomocysteinemia. Steps to either reduce the prevalence of Vitamin B12 Deficiency or to identify and treat individuals with Vitamin B12 Deficiency could further reduce the prevalence of hyperhomocysteinemia.
Alexandra Papaioannou - One of the best experts on this subject based on the ideXlab platform.
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oral Vitamin B12 versus intramuscular Vitamin B12 for Vitamin B12 Deficiency a systematic review of randomized controlled trials
Family Practice, 2006Co-Authors: Christopher C Butler, Josep Vidalalaball, Rebecca Canningsjohn, Kerenza Hood, Andrew Mccaddon, Alexandra Papaioannou, I F W Mcdowell, Andrew GoringeAbstract:Background. Vitamin B12 Deficiency is common, increasing with age. Most people are treated in primary care with intramuscular Vitamin B12. Several studies have reported equal efficacy of oral administration of Vitamin B12. Objectives. We set out to identify randomized controlled trial (RCT) evidence for the effectiveness of oral versus intramuscular Vitamin B12 to treat Vitamin B12 Deficiency. Methods. We conducted a systematic review searching databases for relevant RCTs. Outcomes included levels of serum Vitamin B12, total serum homocysteine and methylmalonic acid, haemoglobin and signs and symptoms of Vitamin B12 Deficiency. Results. Two RCTs comparing oral with intramuscular administration of Vitamin B12 met our inclusion criteria. The trials recruited a total of 108 participants and followed up 93 of these from 90 days to 4 months. In one of the studies, mean serum Vitamin B12 levels were significantly higher in the oral (643 ± 328 pg/ml; n = 18) compared with the intramuscular group (306 ± 118 pg/ml; n = 15) at 2 months (P < 0.001) and 4 months (1005 ± 595 versus 325 ± 165 pg/ml; P < 0.0005) and both groups had neurological responses. In the other study, serum Vitamin B12 levels increased significantly in those receiving oral Vitamin B12 and intramuscular Vitamin B12 (P < 0.001). Conclusions. The evidence derived from these limited studies suggests that 2000 µg doses of oral Vitamin B12 daily and 1000 µg doses initially daily and thereafter weekly and then monthly may be as effective as intramuscular administration in obtaining short-term haematological and neurological responses in Vitamin B12-deficient patients.
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oral Vitamin B12 versus intramuscular Vitamin B12 for Vitamin B12 Deficiency
Cochrane Database of Systematic Reviews, 2005Co-Authors: Josep Vidalalaball, Christopher C Butler, Rebecca Canningsjohn, Andrew Goringe, Kerenza Hood, Andrew Mccaddon, I Mcdowell, Alexandra PapaioannouAbstract:Vitamin B12 Deficiency is common and rises with age. Most people with Vitamin B12 Deficiency are treated in primary care with intramuscular Vitamin B12 which is a considerable source of work for health care professionals. Several case control and case series studies have reported equal efficacy of oral administration of Vitamin B12 but it is rarely prescribed in this form, other than in Sweden and Canada. Doctors may not be prescribing oral formulations because they are unaware of this option or have concerns regarding effectiveness.
Lindsay H Allen - One of the best experts on this subject based on the ideXlab platform.
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Measurement of Total Vitamin B12 and Holotranscobalamin, Singly and in Combination, in Screening for Metabolic Vitamin B12 Deficiency
2015Co-Authors: Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:Background: The standard screening test for Vitamin B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both mea-sures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age>60 years). Plasma methylma-lonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 (<148 pmol/L) and low holoTC (<35 pmol/L) were observed in 6.5 % and 8.0%
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Measurement of Total Vitamin B12 and Holotranscobalamin, Singly and in Combination, in Screening for Metabolic Vitamin B12 Deficiency
2015Co-Authors: Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both mea-sures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age>60 years). Plasma methylma-lonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 (<148 pmol/L) and low holoTC (<35 pmol/L) were observed in 6.5 % and 8.0%, and increased methylmalonic acid (>350 nmol/L) an
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effect of Vitamin B12 Deficiency on neurodevelopment in infants current knowledge and possible mechanisms
Nutrition Reviews, 2008Co-Authors: Daphna K Dror, Lindsay H AllenAbstract:Severe Vitamin B12 Deficiency produces a cluster of neurological symptoms in infants, including irritability, failure to thrive, apathy, anorexia, and developmental regression, which respond remarkably rapidly to supplementation. The underlying mechanisms may involve delayed myelination or demyelination of nerves; alteration in the S-adenosylmethionine:S-adenosylhomocysteine ratio; imbalance of neurotrophic and neurotoxic cytokines; and/or accumulation of lactate in brain cells. This review summarizes the current knowledge concerning infantile Vitamin B12 Deficiency, including a pooled analysis of case studies of infants born to mothers with untreated pernicious anemia or a strict vegetarian lifestyle and a discussion of the mechanisms that may underlie the manifestations of Deficiency.
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measurement of total Vitamin B12 and holotranscobalamin singly and in combination in screening for metabolic Vitamin B12 Deficiency
Clinical Chemistry, 2006Co-Authors: Joshua W Miller, Marjorie G Garrod, Alan L Rockwood, Mark M Kushnir, Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:Background: The standard screening test for Vitamin B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both measures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age ≥60 years). Plasma methylmalonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 ( 350 nmol/L) and homocysteine (>13 μmol/L) were observed in 12.1% and 17.0% of the study participants. In multiple regression models, holoTC explained 5%–6% more of the observed variance in methylmalonic acid and homocysteine than did total Vitamin B12 ( P ≤0.004). ROC curve analysis indicated that total Vitamin B12 and holoTC were essentially equivalent in their ability to discriminate persons with and without Vitamin B12 Deficiency. Individuals with low concentrations of both total Vitamin B12 and holoTC had significantly higher concentrations of methylmalonic acid and homocysteine than did individuals with total Vitamin B12 and/or holoTC within the reference intervals ( P <0.001). Conclusions: HoloTC and total Vitamin B12 have equal diagnostic accuracy in screening for metabolic Vitamin B12 Deficiency. Measurement of both holoTC and total Vitamin B12 provides a better screen for Vitamin B12 Deficiency than either assay alone.
Joshua W Miller - One of the best experts on this subject based on the ideXlab platform.
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measurement of total Vitamin B12 and holotranscobalamin singly and in combination in screening for metabolic Vitamin B12 Deficiency
Clinical Chemistry, 2006Co-Authors: Joshua W Miller, Marjorie G Garrod, Alan L Rockwood, Mark M Kushnir, Lindsay H Allen, Mary N Haan, Ralph GreenAbstract:Background: The standard screening test for Vitamin B12 Deficiency, measurement of total plasma Vitamin B12, has limitations of sensitivity and specificity. Plasma Vitamin B12 bound to transcobalamin (holoTC) is the fraction of total Vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of Vitamin B12 status. Methods: We compared the diagnostic accuracy of total Vitamin B12, holoTC, and a combination of both measures to screen for metabolic Vitamin B12 Deficiency in an elderly cohort (age ≥60 years). Plasma methylmalonic acid and homocysteine were used as indicators of Vitamin B12 Deficiency. Results: Low total Vitamin B12 ( 350 nmol/L) and homocysteine (>13 μmol/L) were observed in 12.1% and 17.0% of the study participants. In multiple regression models, holoTC explained 5%–6% more of the observed variance in methylmalonic acid and homocysteine than did total Vitamin B12 ( P ≤0.004). ROC curve analysis indicated that total Vitamin B12 and holoTC were essentially equivalent in their ability to discriminate persons with and without Vitamin B12 Deficiency. Individuals with low concentrations of both total Vitamin B12 and holoTC had significantly higher concentrations of methylmalonic acid and homocysteine than did individuals with total Vitamin B12 and/or holoTC within the reference intervals ( P <0.001). Conclusions: HoloTC and total Vitamin B12 have equal diagnostic accuracy in screening for metabolic Vitamin B12 Deficiency. Measurement of both holoTC and total Vitamin B12 provides a better screen for Vitamin B12 Deficiency than either assay alone.
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Vitamin B12 Deficiency is the dominant nutritional cause of hyperhomocysteinemia in a folic acid fortified population
Clinical Chemistry and Laboratory Medicine, 2005Co-Authors: Ralph Green, Joshua W MillerAbstract:Prevalence rates for folate Deficiency and hyperhomocysteinemia have been markedly reduced following the introduction of folic acid fortification in the United States. We report the prevalence of hyperhomocysteinemia in a population of community-dwelling elderly Latinos in the post-folic acid fortification era. We measured homocysteine, total Vitamin B12, holotranscobalamin, red blood cell folate, and serum creatinine in 1096 subjects aged > or =60 years. Hyperhomocysteinemia (>13 micromol/L) was observed in 16.5% of the subjects. The population attributable risk percentages for hyperhomocysteinemia were 29.7% for total B12 115 micromol/L. In contrast, the population attributable risk percentage for hyperhomocysteinemia was only 0.3% for red blood cell folate <365 nmol/L. We conclude that in the post-folic acid fortification era, low Vitamin B12 status has become the dominant nutritional determinant of hyperhomocysteinemia. Steps to either reduce the prevalence of Vitamin B12 Deficiency or to identify and treat individuals with Vitamin B12 Deficiency could further reduce the prevalence of hyperhomocysteinemia.
Josep Vidalalaball - One of the best experts on this subject based on the ideXlab platform.
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oral Vitamin B12 versus intramuscular Vitamin B12 for Vitamin B12 Deficiency a systematic review of randomized controlled trials
Family Practice, 2006Co-Authors: Christopher C Butler, Josep Vidalalaball, Rebecca Canningsjohn, Kerenza Hood, Andrew Mccaddon, Alexandra Papaioannou, I F W Mcdowell, Andrew GoringeAbstract:Background. Vitamin B12 Deficiency is common, increasing with age. Most people are treated in primary care with intramuscular Vitamin B12. Several studies have reported equal efficacy of oral administration of Vitamin B12. Objectives. We set out to identify randomized controlled trial (RCT) evidence for the effectiveness of oral versus intramuscular Vitamin B12 to treat Vitamin B12 Deficiency. Methods. We conducted a systematic review searching databases for relevant RCTs. Outcomes included levels of serum Vitamin B12, total serum homocysteine and methylmalonic acid, haemoglobin and signs and symptoms of Vitamin B12 Deficiency. Results. Two RCTs comparing oral with intramuscular administration of Vitamin B12 met our inclusion criteria. The trials recruited a total of 108 participants and followed up 93 of these from 90 days to 4 months. In one of the studies, mean serum Vitamin B12 levels were significantly higher in the oral (643 ± 328 pg/ml; n = 18) compared with the intramuscular group (306 ± 118 pg/ml; n = 15) at 2 months (P < 0.001) and 4 months (1005 ± 595 versus 325 ± 165 pg/ml; P < 0.0005) and both groups had neurological responses. In the other study, serum Vitamin B12 levels increased significantly in those receiving oral Vitamin B12 and intramuscular Vitamin B12 (P < 0.001). Conclusions. The evidence derived from these limited studies suggests that 2000 µg doses of oral Vitamin B12 daily and 1000 µg doses initially daily and thereafter weekly and then monthly may be as effective as intramuscular administration in obtaining short-term haematological and neurological responses in Vitamin B12-deficient patients.
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oral Vitamin B12 versus intramuscular Vitamin B12 for Vitamin B12 Deficiency
Cochrane Database of Systematic Reviews, 2005Co-Authors: Josep Vidalalaball, Christopher C Butler, Rebecca Canningsjohn, Andrew Goringe, Kerenza Hood, Andrew Mccaddon, I Mcdowell, Alexandra PapaioannouAbstract:Vitamin B12 Deficiency is common and rises with age. Most people with Vitamin B12 Deficiency are treated in primary care with intramuscular Vitamin B12 which is a considerable source of work for health care professionals. Several case control and case series studies have reported equal efficacy of oral administration of Vitamin B12 but it is rarely prescribed in this form, other than in Sweden and Canada. Doctors may not be prescribing oral formulations because they are unaware of this option or have concerns regarding effectiveness.
