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Yazidi M, Kammoun E, Oueslati I, Chihaoui M. Metformin-Induced Vitamin B12 Deficiency in Patients with Type 2 Diabetes: A Narrative Review with a Practical Approach for Screening, Diagnosing, and Managing Vitamin B12 Deficiency. Korean J Fam Med 2024; 45:189-198. [PMID: 39054838 PMCID: PMC11273170 DOI: 10.4082/kjfm.24.0090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/27/2024] [Accepted: 06/12/2024] [Indexed: 07/27/2024] Open
Abstract
Metformin is the most widely used antihyperglycemic drug in patients with type 2 diabetes (T2D). Over the past 2 decades, several studies have highlighted a substantial increase in the risk of vitamin B12 deficiency in patients with T2D on metformin therapy. This can lead to several complications and induce or exacerbate peripheral neuropathy. Despite these data, there are no definite guidelines for screening, diagnosing, and treating vitamin B12 deficiency in patients with T2D on metformin therapy. Therefore, in this narrative review, we aimed to suggest a practical diagnostic and therapeutic strategy to address vitamin B12 deficiency in patients with T2D receiving metformin treatment. Clinical evidence supporting an increased risk of vitamin B12 deficiency in patients with T2D on metformin therapy and its risk factors and potential complications are also discussed.
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Affiliation(s)
- Meriem Yazidi
- Department of Endocrinology, La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Elyes Kammoun
- Department of Endocrinology, La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Ibtissem Oueslati
- Department of Endocrinology, La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Melika Chihaoui
- Department of Endocrinology, La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
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2
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Batulwar PS, Anjankar A. Individuals Diagnosed With Type 2 Diabetes Mellitus and the Status of Vitamin B12 Deficiency: A Review. Cureus 2024; 16:e55103. [PMID: 38558585 PMCID: PMC10978817 DOI: 10.7759/cureus.55103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 02/27/2024] [Indexed: 04/04/2024] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder with a multifactorial etiology and a significant global burden. In recent years, emerging evidence has suggested a potential link between T2DM and vitamin B12 deficiency, raising concerns about its impact on disease progression, management, and associated complications. This comprehensive review critically examines the current understanding of the prevalence, risk factors, clinical implications, and management strategies related to vitamin B12 deficiency in individuals diagnosed with T2DM. The review begins by providing an overview of the epidemiology of T2DM and its associated complications, underscoring the need for comprehensive management approaches. Subsequently, it delves into the physiology of vitamin B12, including its sources, absorption mechanisms, and biological functions, laying the groundwork for understanding the potential implications of deficiency in T2DM. A thorough analysis of the literature is conducted to elucidate the prevalence and risk factors of vitamin B12 deficiency in individuals with T2DM, considering factors such as age, duration of diabetes, medication use (e.g., metformin), dietary patterns, and comorbidities. Special attention is given to the role of metformin, the first-line therapy for T2DM, in precipitating or exacerbating vitamin B12 deficiency through mechanisms involving alterations in the gut microbiota and intestinal absorption. The review further explores the clinical manifestations and diagnostic challenges associated with vitamin B12 deficiency in the context of T2DM, emphasizing the importance of recognizing subtle symptoms and implementing appropriate screening protocols. It discusses the potential implications of vitamin B12 deficiency on glycemic control, diabetic neuropathy, cognitive function, cardiovascular health, and overall quality of life in individuals with T2DM. In addressing the management of vitamin B12 deficiency in T2DM, the review examines various therapeutic strategies, including oral and parenteral supplementation, dietary modifications, and lifestyle interventions. It critically evaluates the evidence supporting routine screening for vitamin B12 deficiency in individuals with T2DM and discusses controversies surrounding optimal supplementation protocols, dosing regimens, and monitoring strategies. Furthermore, the review highlights gaps in current knowledge and identifies areas for future research, such as the long-term effects of vitamin B12 supplementation on clinical outcomes in T2DM, the impact of genetic factors on vitamin B12 metabolism, and the potential role of personalized interventions. Overall, this review consolidates existing evidence and provides insights into the complex relationship between T2DM and vitamin B12 deficiency, aiming to inform clinical practice, enhance patient care, and guide future research endeavors in this important area of metabolic medicine.
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Affiliation(s)
- Pratiksha S Batulwar
- Biochemistry, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Ashish Anjankar
- Biochemistry, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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Sayedali E, Yalin AE, Yalin S. Association between metformin and vitamin B12 deficiency in patients with type 2 diabetes. World J Diabetes 2023; 14:585-593. [PMID: 37273250 PMCID: PMC10236989 DOI: 10.4239/wjd.v14.i5.585] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 04/07/2023] [Indexed: 05/15/2023] Open
Abstract
Diabetes mellitus (DM) is still one of the most common diseases worldwide, and its prevalence is still increasing globally. According to the American and European recommendations, metformin is considered a first-line oral hypo-glycemic drug for controlling type 2 DM (T2DM) patients. Metformin is the ninth most often prescribed drug in the world, and at least 120 million diabetic people are estimated to receive the drug. In the last 20 years, there has been increasing evidence of vitamin B12 deficiency among metformin-treated diabetic patients. Many studies have reported that vitamin B12 deficiency is related to the ma-labsorption of vitamin B12 among metformin-treated T2DM patients. Vitamin B12 deficiency may have a very bad complication for the T2DM patient. In this review, we will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption. In addition, the review will describe the clinical outcomes of vitamin B12 deficiency in metformin-treated T2DM.
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Affiliation(s)
- Ehsan Sayedali
- Department of Biochemistry,Faculty of Pharmacy, Mersin University, Mersin 33169, Turkey
| | - Ali Erdinç Yalin
- Department of Biochemistry,Faculty of Pharmacy, Mersin University, Mersin 33169, Turkey
| | - Serap Yalin
- Department of Biochemistry,Faculty of Pharmacy, Mersin University, Mersin 33169, Turkey
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Alhaddad A, Radwan A, Mohamed NA, Mehanna ET, Mostafa YM, El-Sayed NM, Fattah SA. Rosiglitazone Mitigates Dexamethasone-Induced Depression in Mice via Modulating Brain Glucose Metabolism and AMPK/mTOR Signaling Pathway. Biomedicines 2023; 11:biomedicines11030860. [PMID: 36979839 PMCID: PMC10046017 DOI: 10.3390/biomedicines11030860] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Major depressive disorder (MDD) is a common, complex disease with poorly understood pathogenesis. Disruption of glucose metabolism is implicated in the pathogenesis of depression. AMP-activated protein kinase (AMPK) has been shown to regulate the activity of several kinases, including pAKT, p38MAPK, and mTOR, which are important signaling pathways in the treatment of depression. This study tested the hypothesis that rosiglitazone (RGZ) has an antidepressant impact on dexamethasone (DEXA)-induced depression by analyzing the function of the pAKT/p38MAPK/mTOR pathway and NGF through regulation of AMPK. MDD-like pathology was induced by subcutaneous administration of DEXA (20 mg/kg) for 21 days in all groups except in the normal control group, which received saline. To investigate the possible mechanism of RGZ, the protein expression of pAMPK, pAKT, p38MAPK, and 4EBP1 as well as the levels of hexokinase, pyruvate kinase, and NGF were assessed in prefrontal cortex and hippocampal samples. The activities of pAMPK and NGF increased after treatment with RGZ. The administration of RGZ also decreased the activity of mTOR as well as downregulating the downstream signaling pathways pAKT, p38MAPK, and 4EBP1. Here, we show that RGZ exerts a potent inhibitory effect on the pAKT/p38MAPK/mTOR/4EBP1 pathway and causes activation of NGF in brain cells. This study has provided sufficient evidence of the potential for RGZ to ameliorate DEXA-induced depression. A new insight has been introduced into the critical role of NGF activation in brain cells in depression. These results suggest that RGZ is a promising antidepressant for the treatment of MDD.
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Affiliation(s)
- Aisha Alhaddad
- Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Al-Madinah Al-Munawwarah 30078, Saudi Arabia
| | - Asmaa Radwan
- Department of Pharmacology &Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
| | - Noha A. Mohamed
- Department of Forgery & Counterfeiting, Forensic Medicine, Ministry of Justice, Ismailia 41522, Egypt
| | - Eman T. Mehanna
- Department of Biochemistry & Molecular Biology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
- Correspondence: (E.T.M.); (N.M.E.-S.)
| | - Yasser M. Mostafa
- Department of Pharmacology &Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
- Department of Pharmacology & Toxicology, Faculty of Pharmacy, Badr University in Cairo, Badr 11829, Egypt
| | - Norhan M. El-Sayed
- Department of Pharmacology &Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
- Correspondence: (E.T.M.); (N.M.E.-S.)
| | - Shaimaa A. Fattah
- Department of Biochemistry & Molecular Biology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
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The antidiabetic drug metformin aids bacteria in hijacking vitamin B12 from the environment through RcdA. Commun Biol 2023; 6:96. [PMID: 36693976 PMCID: PMC9873799 DOI: 10.1038/s42003-023-04475-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/12/2023] [Indexed: 01/25/2023] Open
Abstract
Years of use of the antidiabetic drug metformin has long been associated with the risk of vitamin B12 (B12) deficiency in type 2 diabetes (T2D) patients, although the underlying mechanisms are unclear. Accumulating evidence has shown that metformin may exert beneficial effects by altering the metabolism of the gut microbiota, but whether it induces human B12 deficiency via modulation of bacterial activity remains poorly understood. Here, we show that both metformin and the other biguanide drug phenformin markedly elevate the accumulation of B12 in E. coli. By functional and genomic analysis, we demonstrate that both biguanides can significantly increase the expression of B12 transporter genes, and depletions of vital ones, such as tonB, nearly completely abolish the drugs' effect on bacterial B12 accumulation. Via high-throughput screens in E. coli and C. elegans, we reveal that the TetR-type transcription factor RcdA is required for biguanide-mediated promotion of B12 accumulation and the expressions of B12 transporter genes in bacteria. Together, our study unveils that the antidiabetic drug metformin helps bacteria gather B12 from the environment by increasing the expressions of B12 transporter genes in an RcdA-dependent manner, which may theoretically reduce the B12 supply to T2D patients taking the drug over time.
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Rzepka Z, Rok J, Kowalska J, Banach K, Wrześniok D. Cobalamin Deficiency May Induce Astrosenescence-An In Vitro Study. Cells 2022; 11:3408. [PMID: 36359805 PMCID: PMC9655094 DOI: 10.3390/cells11213408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 11/30/2022] Open
Abstract
Cobalamin (vitamin B12) deficiency is one of the major factors causing degenerative changes in the nervous system and, thus, various neurological and psychiatric symptoms. The underlying cellular mechanism of this phenomenon is not yet fully understood. An accumulation of senescent astrocytes has been shown to contribute to a wide range of pathologies of the nervous system, including neurodegenerative disorders. This study aimed to investigate whether cobalamin deficiency triggers astrosenescence. After inducing cobalamin deficiency in normal human astrocytes in vitro, we examined biomarkers of cellular senescence: SA-β-gal, p16INK4A, and p21Waf1/Cip1 and performed cell nuclei measurements. The obtained results may contribute to an increase in the knowledge of the cellular effects of cobalamin deficiency in the context of astrocytes. In addition, the presented data suggest a potential causative agent of astrosenescence that has not been proven to date.
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Affiliation(s)
- Zuzanna Rzepka
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 4 Jagiellońska Str., 41-200 Sosnowiec, Poland
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Wei J, Wei Y, Huang M, Wang P, Jia S. Is metformin a possible treatment for diabetic neuropathy? J Diabetes 2022; 14:658-669. [PMID: 36117320 PMCID: PMC9574743 DOI: 10.1111/1753-0407.13310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 12/04/2022] Open
Abstract
Metformin is a hypoglycemic drug widely used in the treatment of type 2 diabetes. It has been proven to have analgesic and neuroprotective effects. Metformin can reverse pain in rodents, such as diabetic neuropathic pain, neuropathic pain caused by chemotherapy drugs, inflammatory pain and pain caused by surgical incision. In clinical use, however, metformin is associated with reduced plasma vitamin B12 levels, which can further neuropathy. In rodent diabetes models, metformin plays a neuroprotective and analgesic role by activating adenosine monophosphate-activated protein kinase, clearing methylgloxal, reducing insulin resistance, and neuroinflammation. This paper also summarized the neurological adverse reactions of metformin in diabetic patients. In addition, whether metformin has sexual dimorphism needs further study.
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Affiliation(s)
- Juechun Wei
- The Second Medical CollegeBinzhou Medical UniversityYantaiChina
| | - Yanling Wei
- Qingdao Dongheng Zhiyuan Automobile Service Co. LTDQingdaoChina
| | - Meiyan Huang
- The Second Medical CollegeBinzhou Medical UniversityYantaiChina
| | - Peng Wang
- The Second Medical CollegeBinzhou Medical UniversityYantaiChina
| | - Shushan Jia
- Yantai Affiliated Hospital of Binzhou Medical UniversityYantaiChina
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Kwape L, Ocampo C, Oyekunle A, Mwita JC. Vitamin B12 deficiency in patients with diabetes at a specialised diabetes clinic, Botswana. JOURNAL OF ENDOCRINOLOGY, METABOLISM AND DIABETES OF SOUTH AFRICA 2021. [DOI: 10.1080/16089677.2021.1927586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- L Kwape
- Department of Medicine, Princess Marina Hospital, Gaborone, Botswana
| | - C Ocampo
- Department of Medicine, Princess Marina Hospital, Gaborone, Botswana
- Department of Internal Medicine, University of Botswana, Gaborone, Botswana
| | - A Oyekunle
- Department of Medicine, Princess Marina Hospital, Gaborone, Botswana
- Department of Internal Medicine, University of Botswana, Gaborone, Botswana
| | - JC Mwita
- Department of Medicine, Princess Marina Hospital, Gaborone, Botswana
- Department of Internal Medicine, University of Botswana, Gaborone, Botswana
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Wu Y, Zhang L, Li S, Zhang D. Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis. Nutr Rev 2021; 80:351-366. [PMID: 33912967 DOI: 10.1093/nutrit/nuab014] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/12/2021] [Accepted: 02/24/2021] [Indexed: 01/24/2023] Open
Abstract
CONTEXT The results from epidemiologic studies on the intake of dietary vitamin B1, B2, B6, and B12 and association with risk of developing depression have been inconsistent. OBJECTIVE The purpose of this systematic review and meta-analysis was to summarize the existing evidence and synthesize the results. DATA SOURCES The databases of Web of Science and PubMed were searched for relevant articles published in English until September 2020. STUDY SELECTION Observational studies that evaluated the associations between depression and dietary vitamin B1, B2, B6, and B12 were included in this study. DATA EXTRACTION The job of data extraction was undertaken by 2 authors, and the pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a fixed-effects model. RESULTS Thirteen articles related to 18 studies were eligible for inclusion in this systematic review and meta-analysis. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B1, B2, B6, and B12 was 0.69 (0.55-0.87), 0.77 (0.67-0.89), 0.81 (0.71-0.93), and 0.86 (0.75-0.99), respectively. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B2 was 0.80 (0.64-0.99) in females and 0.83 (0.67-1.02) in males, for dietary vitamin B6 was 0.71 (0.59-0.86) in females and 0.92 (0.76-1.12) in males, and for dietary vitamin B12 was 0.79 (0.65-0.97) in females and 0.94 (0.77-1.15) in males. CONCLUSION This study suggested that the intake of dietary vitamin B1, B2, B6, and B12 may be inversely associated with the risk of depression; the inverse associations observed between depression and intake of dietary vitamin B2, B6, and B12 were significant in females, but not in males. Further studies are needed to confirm these results.
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Affiliation(s)
- Yanjun Wu
- Y. Wu, L. Zhang, S. Li, and D. Zhang are with the Department of Epidemiology and Health Statistics, the College of Public Health of Qingdao University, Qingdao, People's Republic of China
| | - Liming Zhang
- Y. Wu, L. Zhang, S. Li, and D. Zhang are with the Department of Epidemiology and Health Statistics, the College of Public Health of Qingdao University, Qingdao, People's Republic of China
| | - Suyun Li
- Y. Wu, L. Zhang, S. Li, and D. Zhang are with the Department of Epidemiology and Health Statistics, the College of Public Health of Qingdao University, Qingdao, People's Republic of China
| | - Dongfeng Zhang
- Y. Wu, L. Zhang, S. Li, and D. Zhang are with the Department of Epidemiology and Health Statistics, the College of Public Health of Qingdao University, Qingdao, People's Republic of China
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Stein J, Geisel J, Obeid R. Association between neuropathy and B-vitamins: A systematic review and meta-analysis. Eur J Neurol 2021; 28:2054-2064. [PMID: 33619867 DOI: 10.1111/ene.14786] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/04/2021] [Accepted: 02/18/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Peripheral neuropathy (PN) is common in patients with diseases that are in turn associated with deficiency of the B-vitamins, and vitamin treatment has shown mixed results. METHODS This systematic review and meta-analysis studied the association between PN/pain and B-vitamin biomarkers and investigated whether vitamin treatment can ameliorate the symptoms. PubMed and Web of Science were searched according to the study protocol. RESULTS A total of 46 observational and seven interventional studies were identified and included in the data synthesis. The presence of PN was associated with lowered B12 levels (pooled estimate [95% CIs] = 1.51 [1.23-1.84], n = 34, Cochran Q Test I2 = 43.3%, p = 0.003) and elevated methylmalonic acid (2.53 [1.39-4.60], n = 9, I2 = 63.8%, p = 0.005) and homocysteine (3.48 [2.01-6.04], n = 15, I2 = 70.6%, p < 0.001). B12 treatment (vs. the comparators) showed a non-significant association with symptom improvement (1.36 (0.66-2.79), n = 4, I2 = 28.9%). Treatment with B1 was associated with a significant improvement in symptoms (5.34 [1.87-15.19], n = 3, I2 = 64.6%, p = 0.059). Analysis of seven trials combined showed a non-significant higher odds ratio for improvement under treatment with the B-vitamins (2.58 [0.98-6.79], I2 = 80.0%, p < 0.001). CONCLUSIONS PN is associated with lowered plasma vitamin B12 and elevated methylmalonic acid and homocysteine. Overall, interventional studies have suggested that B-vitamins could improve symptoms of PN. Available trials have limitations and generally did not investigate vitamin status prior to treatment. Well-designed studies, especially in non-diabetes PN, are needed. This meta-analysis is registered at PROSPERO (ID: CRD42020144917).
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Affiliation(s)
- Johannes Stein
- Saarland University, Saarbrucken, Germany.,Department of Clinical Chemistry and Laboratory Medicine, Saarland University Hospital, Homburg, Germany
| | - Juergen Geisel
- Department of Clinical Chemistry and Laboratory Medicine, Saarland University Hospital, Homburg, Germany
| | - Rima Obeid
- Department of Clinical Chemistry and Laboratory Medicine, Saarland University Hospital, Homburg, Germany
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Gökışık MT, Uyar S. The role of Helicobacter pylori in vitamin-B 12 deficiency due to metformin use. Helicobacter 2020; 25:e12718. [PMID: 32559822 DOI: 10.1111/hel.12718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Metformin is widely used for the treatment of type-2 diabetes (T2D) but was shown to cause vitamin-B12 deficiency. H pylori infection was also suggested to cause vitamin-B12 deficiency. This study aimed to elucidate the relationships in this triad by investigating vitamin-B12 deficiency and H pylori infection in T2D patients using metformin. MATERIALS AND METHODS This descriptive cross-sectional study recruited T2D patients using metformin from a primary care center and examined their socioeconomic status, accompanying complaints, medication use, and hemogram parameters such as serum vitamin B12 , calcium, and hemoglobin. The presence of H pylori infection was determined through stool antigen test. RESULTS Study included 421 T2D patients on metformin regimen: 213 (50.6%) males and 208 (49.4%) females. The mean duration of diabetes was 9.88 ± 7.32 years, and the total metformin dose was 1925.5 ± 236.7 mg/d. Almost half of the participants (n = 199, 47.3%) had H pylori infection, and more than half (n = 222, 52.7%) had vitamin-B12 deficiency. The rate of vitamin-B12 deficiency was significantly higher among those with H pylori infection. No significant relationship was found between the daily metformin dose and vitamin-B12 deficiency. CONCLUSIONS This study supported the role of H pylori infection in vitamin-B12 deficiency. However, the effects of increased metformin dose and H pylori infection on vitamin-B12 levels were not additive. It is recommended that vitamin-B12 levels in T2D patients are monitored and those with vitamin-B12 deficiency, regardless of metformin dose, are screened for H pylori and, if necessary, treated.
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Affiliation(s)
- Melih Tansel Gökışık
- Department of Family Medicine, Antalya Training and Research Hospital, Health Sciences University, Antalya, Turkey
| | - Seyit Uyar
- Department of Internal Medicine, Antalya Training and Research Hospital, Health Sciences University, Antalya, Turkey
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Runeberg HA, Higbea AM, Weideman RA, Alvarez CA. Evaluation of Vitamin B 12 Monitoring in Veterans With Type 2 Diabetes on Metformin Therapy. J Pharm Pract 2020; 34:715-720. [PMID: 31955662 DOI: 10.1177/0897190019899260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Studies have shown an association between metformin use and vitamin B12 deficiency. Since 2017, the American Diabetes Association (ADA) Standards of Medical Care in Diabetes Guideline has included a recommendation for periodic vitamin B12 measurements in metformin-treated patients, especially those with anemia or peripheral neuropathy. OBJECTIVE To determine the overall incidence and impact of the ADA Guideline on vitamin B12 monitoring in a veteran population on long-term metformin therapy. METHODS Retrospective chart review was performed for patients on metformin who started therapy prior to 2005 at the VA North Texas Health Care System (VANTXHCS). The primary outcome was the proportion of patients with at least 1 vitamin B12 level drawn during 2016 versus 2018. Metformin dose and duration, vitamin B12 supplementation, and incident neuropathy prescriptions or diagnosis were also analyzed. RESULTS Of 394 patients included for the primary outcome, 136 (34.5%) had at least 1 vitamin B12 level in 2016 versus 198 (50.3%) patients in 2018 (odds ratio: 1.94, P < .001). Of the 394 patients, 157 were diagnosed with neuropathy or prescribed a medication for neuropathy without a vitamin B12 level in the previous year or with a low level that was not supplemented. CONCLUSION Vitamin B12 monitoring significantly increased between 2016 and 2018, aligning with the release of the 2017 ADA guidelines. However, a large proportion of patients were identified who were diagnosed with or treated for neuropathy without adequate vitamin B12 monitoring.
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Affiliation(s)
| | - Ashley M Higbea
- Texas Tech University Health Sciences Center, Jerry H. Hodge School of Pharmacy, Dallas, TX, USA
| | | | - Carlos A Alvarez
- Texas Tech University Health Sciences Center, Jerry H. Hodge School of Pharmacy, Dallas, TX, USA
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14
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Metformin and cognition from the perspectives of sex, age, and disease. GeroScience 2020; 42:97-116. [PMID: 31897861 DOI: 10.1007/s11357-019-00146-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022] Open
Abstract
Metformin is the safest and the most widely prescribed first-line therapy for managing hyperglycemia due to different underlying causes, primarily type 2 diabetes mellitus. In addition to its euglycemic properties, metformin has stimulated a wave of clinical trials to investigate benefits on aging-related diseases and longevity. Such an impact on the lifespan extension would undoubtedly expand the therapeutic utility of metformin regardless of glycemic status. However, there is a scarcity of studies evaluating whether metformin has differential cognitive effects across age, sex, glycemic status, metformin dose, and duration of metformin treatment and associated pathological conditions. By scrutinizing the available literature on animal and human studies for metformin and brain function, we expect to shed light on the potential impact of metformin on cognition across age, sex, and pathological conditions. This review aims to provide readers with a broader insight of (a) how metformin differentially affects cognition and (b) why there is a need for more translational and clinical studies examining multifactorial interactions. The outcomes of such comprehensive studies will streamline precision medicine practices, avoiding "fit for all" approach, and optimizing metformin use for longevity benefit irrespective of hyperglycemia.
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Simkin AJ. Genetic Engineering for Global Food Security: Photosynthesis and Biofortification. PLANTS (BASEL, SWITZERLAND) 2019; 8:E586. [PMID: 31835394 PMCID: PMC6963231 DOI: 10.3390/plants8120586] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 12/18/2022]
Abstract
Increasing demands for food and resources are challenging existing markets, driving a need to continually investigate and establish crop varieties with improved yields and health benefits. By the later part of the century, current estimates indicate that a >50% increase in the yield of most of the important food crops including wheat, rice and barley will be needed to maintain food supplies and improve nutritional quality to tackle what has become known as 'hidden hunger'. Improving the nutritional quality of crops has become a target for providing the micronutrients required in remote communities where dietary variation is often limited. A number of methods to achieve this have been investigated over recent years, from improving photosynthesis through genetic engineering, to breeding new higher yielding varieties. Recent research has shown that growing plants under elevated [CO2] can lead to an increase in Vitamin C due to changes in gene expression, demonstrating one potential route for plant biofortification. In this review, we discuss the current research being undertaken to improve photosynthesis and biofortify key crops to secure future food supplies and the potential links between improved photosynthesis and nutritional quality.
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Affiliation(s)
- Andrew John Simkin
- Genetics, Genomics and Breeding, NIAB EMR, East Malling, Kent, ME19 6BJ, UK
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Risk factors for depression in elderly diabetic patients and the effect of metformin on the condition. BMC Public Health 2019; 19:1063. [PMID: 31391021 PMCID: PMC6686369 DOI: 10.1186/s12889-019-7392-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 07/29/2019] [Indexed: 11/10/2022] Open
Abstract
Background At present, only a few studies have focused on the risk factors for depression in elderly diabetic patients, and there is little evidence for the effect of metformin in depressed elderly patients with diabetes than on its effect on blood glucose. The aim of the current work was to study the risk factors for depression in elderly diabetic patients and to ascertain the effects of metformin on the depressive state. Methods We initiated a 1:4 matched case–control study. The case group comprised 110 elderly diabetic patients with depression from nine communities in Shenyang in 2017. The control group comprised 440 non-depressed elderly diabetic patients from the same communities, which were matched by gender and age (± 2 years of age) with the case group. Depression was measured using the Geriatric Depression Scale-15, and we performed matched univariate and multivariate logistic regression analyses. Results In the multivariate analysis, overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly patients with diabetes. For these risk factors, the adjusted ORs (all P < 0.05) were as follows: an adjusted OR of 2.031 and 95% CI of 1.180–3.495; an adjusted OR of 2.342 and 95% CI of 1.465–3.743; and an adjusted OR of 5.350 and 95% CI of 2.222–12.883, respectively. Patients taking metformin had a lower risk of depression than those taking no medication, with an adjusted OR of 0.567 and 95% CI of 0.323–0.997 (P < 0.05). Conclusions Overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly diabetic patients, and metformin was a protective factor against depression in elderly diabetic patients.
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McMillan JM, Mele BS, Hogan DB, Leung AA. Impact of pharmacological treatment of diabetes mellitus on dementia risk: systematic review and meta-analysis. BMJ Open Diabetes Res Care 2018; 6:e000563. [PMID: 30487973 PMCID: PMC6254737 DOI: 10.1136/bmjdrc-2018-000563] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/11/2018] [Accepted: 10/01/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The association between diabetes mellitus (DM) treatment and dementia is not well understood. OBJECTIVE To investigate the association between treatment of diabetes, hypoglycemia, and dementia risk. RESEARCH DESIGN AND METHODS We performed a systematic review and meta-analysis of pharmacological treatment of diabetes and incident or progressive cognitive impairment. We searched Ovid MEDLINE, Embase, Cochrane Central Registry of Controlled Trials, and PsychINFO from inception to 18 October 2017. We included cross-sectional, case-control, cohort, and randomized controlled studies. The study was registered with PROSPERO (ID CRD42017077953). RESULTS We included 37 studies into our systematic review and 13 into our meta-analysis. Ten studies investigated any antidiabetic treatment compared with no treatment or as add-on therapy to prior care. Treatment with an antidiabetic agent, in general, was not associated with incident dementia (risk ratio (RR) 1.01; 95% CI 0.93 to 1.10). However, we found differential effects across drug classes, with a signal of harm associated with insulin therapy (RR 1.21; 95% CI 1.06 to 1.39), but potentially protective effects with thiazolidinedione exposure (RR 0.71; 95% CI 0.55 to 0.93). Severe hypoglycemic episodes were associated with a nearly twofold increased likelihood of incident dementia (RR 1.77; 95% CI 1.35 to 2.33). Most studies did not account for DM duration or severity. CONCLUSIONS AND LIMITATIONS The association between treatment for diabetes and dementia is differential according to drug class, which is potentially mediated by hypoglycemic risk. Not accounting for DM duration and/or severity is a major limitation in the available evidence base.
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Affiliation(s)
- Jacqueline M McMillan
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Bria S Mele
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - David B Hogan
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
| | - Alexander A Leung
- Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
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SERUM COBALAMIN AND FOLATE CONCENTRATIONS AS INDICATORS OF GASTROINTESTINAL DISEASE IN KILLER WHALES ( ORCINUS ORCA). J Zoo Wildl Med 2018; 49:564-572. [PMID: 30212340 DOI: 10.1638/2017-0102.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cobalamin and folate are water-soluble vitamins that are useful indicators of chronic gastrointestinal (GI) function in humans and some animal species. Serum cobalamin and folate concentrations in an ex situ population of killer whales ( Orcinus orca) were measured and factors that may affect their serum concentrations were identified. Serum samples ( n = 104) were analyzed from killer whales ( n = 10) both while clinically healthy and during periods of clinical GI disease as defined by clinical signs and fecal cytology. To characterize serum cobalamin and folate concentrations in clinically healthy animals, a mixed-model regression was used, with cobalamin and folate both significantly affected by weight (cobalamin: P < 0.0001, folate: P = 0.006) and season (cobalamin: P < 0.0001, folate: P < 0.0001). The marginal mean concentrations for cobalamin and folate across weight and season were 742 ± 53.6 ng/L and 30.2 ± 2.6 μg/L, respectively. The predicted 95% confidence intervals (CI) for these analytes were then compared with samples collected during periods of GI disease. Across individuals, 22% (2/9) of the folate and 80% (8/10) of the cobalamin samples from the animals with GI disease fell outside the 95% CI for the population. When comparing samples within an individual, a similar pattern presented, with 100% of cobalamin of the observed abnormal samples reduced compared to healthy animal concentration variability. The same was not true for folate. These results suggest that serum concentrations of cobalamin and folate may be useful minimally invasive markers to identify GI disease in killer whales, especially when values are compared within an individual.
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Zhao Z, Zhang L, Guo XD, Cao LL, Xue TF, Zhao XJ, Yang DD, Yang J, Ji J, Huang JY, Sun XL. Rosiglitazone Exerts an Anti-depressive Effect in Unpredictable Chronic Mild-Stress-Induced Depressive Mice by Maintaining Essential Neuron Autophagy and Inhibiting Excessive Astrocytic Apoptosis. Front Mol Neurosci 2017; 10:293. [PMID: 28959186 PMCID: PMC5603714 DOI: 10.3389/fnmol.2017.00293] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/31/2017] [Indexed: 12/28/2022] Open
Abstract
There is increasing interest in the association between depression and the development of metabolic diseases. Rosiglitazone, a therapeutic drug used to treat type 2 diabetes mellitus, has shown neuroprotective effects in patients with stroke and Alzheimer's disease. The present study was performed to evaluate the possible roles of rosiglitazone in in vivo (unpredictable chronic mild stress-induced depressive mouse model) and in vitro (corticosterone-induced cellular model) depressive models. The results showed that rosiglitazone reversed depressive behaviors in mice, as indicated by the forced swimming test and open field test. Rosiglitazone was also found to inhibit the inflammatory response, decrease corticosterone levels, and promote astrocyte proliferation and neuronal axon plasticity in the prefrontal cortex of mice. This series of in vivo and in vitro experiments showed that autophagy among neurons was inhibited in depressive models and that rosiglitazone promoted autophagy by upregulating LKB1, which exerted neuroprotective effects. Rosiglitazone was also found to activate the Akt/CREB pathway by increasing IGF-1R expression and IGF-1 protein levels, thereby playing an anti-apoptotic role in astrocytes. Rosiglitazone's autophagy promotion and neuroprotective effects were found to be reversed by the PPARγ antagonist T0070907 in primary neurons and by PPARγ knockdown in an N2a cell line. In conclusion, we found that rosiglitazone protects both neurons and astrocytes in in vivo and in vitro depressive models, thereby playing an anti-depressive role. These findings suggest that PPARγ could be a new target in the development of anti-depressive drugs.
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Affiliation(s)
- Zhan Zhao
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Ling Zhang
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Xu-Dong Guo
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Lu-Lu Cao
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Teng-Fei Xue
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Xiao-Jie Zhao
- Neuroprotective Drug Discovery Key Laboratory, Department of Forensic Medicine, Nanjing Medical UniversityNanjing, China
| | - Dan-Dan Yang
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Jin Yang
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Juan Ji
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Ji-Ye Huang
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
| | - Xiu-Lan Sun
- Neuroprotective Drug Discovery Key Laboratory, Department of Pharmacology, Nanjing Medical UniversityNanjing, China
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Metformin Use and Vitamin B12 Deficiency: Untangling the Association. Am J Med Sci 2017; 354:165-171. [PMID: 28864375 DOI: 10.1016/j.amjms.2017.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/25/2017] [Accepted: 04/17/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Current evidence linking vitamin B12 deficiency with metformin use is inconsistent. Hence, there is uncertainty regarding the diagnostic approach in this scenario. Furthermore, this possible association has not been studied in the complete spectrum of patients with diabetes. MATERIALS AND METHODS We conducted a cross-sectional, controlled study with the objective of assessing differences in serum vitamin B12 levels among patients with and without diabetes with different metformin-treatment regimens. A total of 150 participants were recruited: patients with diabetes (group 1: metformin alone ≥850mg/day, group 2: patients with type 2 diabetes naive to treatment and group 3: metformin ≥850mg/day, in addition to any other oral glucose lowering agent or insulin, or both) and without diabetes (group 4: polycystic ovary syndrome or group 5: healthy individuals). Serum vitamin B12, folate levels and complete blood counts were obtained for the entire population. Methylmalonic acid and homocysteine were obtained for patients when vitamin B12 levels were found to be borderline or low. RESULTS When patients with or without diabetes were compared, no significant difference was found in relation to their vitamin B12 levels (517.62 versus 433.83; P = 0.072). No difference in vitamin B12 levels was found among participants with metformin use and metformin naive participants (503.4 versus 462.3; P = 0.380). CONCLUSIONS Irrespective of metformin use, no significant difference in the serum levels of vitamin B12 was observed, both in patients with and without diabetes. In the light of the body of evidence and the results of this study, a universal recommendation for vitamin B12 deficiency screening cannot be made.
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Green R, Allen LH, Bjørke-Monsen AL, Brito A, Guéant JL, Miller JW, Molloy AM, Nexo E, Stabler S, Toh BH, Ueland PM, Yajnik C. Vitamin B 12 deficiency. Nat Rev Dis Primers 2017; 3:17040. [PMID: 28660890 DOI: 10.1038/nrdp.2017.40] [Citation(s) in RCA: 465] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Vitamin B12 (B12; also known as cobalamin) is a B vitamin that has an important role in cellular metabolism, especially in DNA synthesis, methylation and mitochondrial metabolism. Clinical B12 deficiency with classic haematological and neurological manifestations is relatively uncommon. However, subclinical deficiency affects between 2.5% and 26% of the general population depending on the definition used, although the clinical relevance is unclear. B12 deficiency can affect individuals at all ages, but most particularly elderly individuals. Infants, children, adolescents and women of reproductive age are also at high risk of deficiency in populations where dietary intake of B12-containing animal-derived foods is restricted. Deficiency is caused by either inadequate intake, inadequate bioavailability or malabsorption. Disruption of B12 transport in the blood, or impaired cellular uptake or metabolism causes an intracellular deficiency. Diagnostic biomarkers for B12 status include decreased levels of circulating total B12 and transcobalamin-bound B12, and abnormally increased levels of homocysteine and methylmalonic acid. However, the exact cut-offs to classify clinical and subclinical deficiency remain debated. Management depends on B12 supplementation, either via high-dose oral routes or via parenteral administration. This Primer describes the current knowledge surrounding B12 deficiency, and highlights improvements in diagnostic methods as well as shifting concepts about the prevalence, causes and manifestations of B12 deficiency.
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Affiliation(s)
- Ralph Green
- Department of Pathology and Laboratory Medicine, University of California Davis, 4400 V Street, PATH Building, Davis, California 95817, USA
| | - Lindsay H Allen
- USDA, ARS Western Human Nutrition Research Center, University of California Davis, Davis, California, USA
| | | | - Alex Brito
- USDA, ARS Western Human Nutrition Research Center, University of California Davis, Davis, California, USA
| | - Jean-Louis Guéant
- Inserm UMRS 954 N-GERE (Nutrition Génétique et Exposition aux Risques Environnementaux), University of Lorraine and INSERM, Nancy, France
| | - Joshua W Miller
- School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Anne M Molloy
- School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Ebba Nexo
- Department of Clinical Medicine, Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Sally Stabler
- Department of Medicine, University of Colorado Denver, Denver, Colorado, USA
| | - Ban-Hock Toh
- Centre for Inflammatory Diseases, Monash Institute of Medical Research, Clayton, Victoria, Australia
| | - Per Magne Ueland
- Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway.,Section for Pharmacology, Department of Clinical Science, University of Bergen, Bergen, Norway
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Association studies of genetic scores of serum vitamin B12 and folate levels with symptoms of depression and anxiety in two danish population studies. Eur J Clin Nutr 2017; 71:1054-1060. [DOI: 10.1038/ejcn.2017.97] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 03/16/2017] [Accepted: 05/10/2017] [Indexed: 11/08/2022]
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Ahmed MA, Muntingh GL, Rheeder P. Perspectives on Peripheral Neuropathy as a Consequence of Metformin-Induced Vitamin B12 Deficiency in T2DM. Int J Endocrinol 2017; 2017:2452853. [PMID: 28932240 PMCID: PMC5591993 DOI: 10.1155/2017/2452853] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/31/2017] [Indexed: 12/15/2022] Open
Abstract
Peripheral neuropathy (PN) is a primary complication of type 2 diabetes mellitus (T2DM) and a direct manifestation of vitamin B12 deficiency. Examining the effects of metformin use on PN status became imperative following clinical studies that showed the vitamin B12-lowering effect of the medication. The complexity of the topic and the inconsistency of the results warrant consideration of topic-specific perspectives for better understanding of the available evidence and more appropriate design of future studies.
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Affiliation(s)
- Marwan A. Ahmed
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- *Marwan A. Ahmed:
| | - George L. Muntingh
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Paul Rheeder
- Department of Internal Medicine, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa
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Ahmed MA, Muntingh G, Rheeder P. Vitamin B12 deficiency in metformin-treated type-2 diabetes patients, prevalence and association with peripheral neuropathy. BMC Pharmacol Toxicol 2016; 17:44. [PMID: 27716423 PMCID: PMC5054613 DOI: 10.1186/s40360-016-0088-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 09/07/2016] [Indexed: 12/21/2022] Open
Abstract
Background The association between long-term metformin use and low vitamin B12 levels has been proven. However, the prevalence estimates of metformin-induced vitamin B12 deficiency showed considerable variation among the studies. The potential of the deficiency to cause or worsen peripheral neuropathy in type-2 diabetes mellitus (T2DM) patients has been investigated with conflicting results. The aim of the study was to investigate: 1) the prevalence of vitamin B12 deficiency in T2DM patients on metformin; 2) the association between vitamin B12 and peripheral neuropathy; 3) and the risk factors for vitamin B12 deficiency in these patients. Methods In this cross-sectional study, consecutive metformin-treated T2DM patients attending diabetes clinics of two public hospitals in South Africa were approached for participation. Participation included measuring vitamin B12 levels and assessing peripheral neuropathy using Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire. The prevalence of vitamin B12 deficiency (defined by concentrations <150 pmol/L) was determined. Those with NTSS-6 scores >6 were considered to have peripheral neuropathy. The relationship between vitamin B12 and peripheral neuropathy was investigated when the two variables were in the binary and continuous forms. Multiple logistic regression was used to determine risk factors for vitamin B12 deficiency. Results Among 121 participants, the prevalence of vitamin B12 deficiency was 28.1 %. There was no difference in presence of neuropathy between those with normal and deficient vitamin levels (36.8 % vs. 32.3 %, P = 0.209). Vitamin B12 levels and NTSS-6 scores were not correlated (Spearman’s rho =0.056, P = 0.54). HbA1c (mmol/mol) (OR = 0.97, 95 % CI: 0.95 to 0.99, P = 0.003) and black race (OR = 0.34, 95 % CI: 0.13 to 0.92, P = 0.033) were risk factors significantly associated with vitamin B12 deficiency. Metformin daily dose (gram) showed borderline significance (OR = 1.96, 95 % CI: 0.99 to 3.88, P = 0.053). Conclusions Close to third of metformin-treated T2DM patients had vitamin B12 deficiency. The deficiency was not associated with peripheral neuropathy. Black race was a protective factor for vitamin B12 deficiency.
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Affiliation(s)
- Marwan A Ahmed
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
| | - George Muntingh
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Paul Rheeder
- Department of Internal Medicine, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa
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Akabwai GP, Kibirige D, Mugenyi L, Kaddu M, Opio C, Lalitha R, Mutebi E, Sajatovic M. Vitamin B12 deficiency among adult diabetic patients in Uganda: relation to glycaemic control and haemoglobin concentration. J Diabetes Metab Disord 2016; 15:26. [PMID: 27468410 PMCID: PMC4962419 DOI: 10.1186/s40200-016-0250-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/20/2016] [Indexed: 12/21/2022]
Abstract
Background Vitamin B12 deficiency is highly prevalent among adult individuals with diabetes yet screening is infrequent in Uganda. There are currently no published data regarding the prevalence of vitamin B12 deficiency and its associated factors among adult individuals with diabetes in sub-Saharan Africa. This study aimed at describing the prevalence and factors associated with vitamin B12 deficiency among this patient population in a resource constrained setting in sub-Saharan Africa. Methods In this cross-sectional study, 280 eligible study participants attending the outpatient diabetic clinic at Mulago national referral and teaching hospital in Kampala, Uganda were enrolled. Their socio-demographic, clinical and laboratory data was collected using a pre-tested questionnaire. Results The majority of the study participants were female (68.9 %), with a median age of 50 (IQR: 40–58) years. The mean (SD) serum vitamin B12 levels was 472.0 (16.4) pg/ml. The prevalence of vitamin B12 deficiency was 10.7 %. Hemoglobin level < 12 g/dl (AOR 3.38; 95 % CI 1.38–8.32, p value = 0.008) and glycated hemoglobin ≥ 7 % (AOR 3.29; 1.44–7.51, p value = 0.005) were associated with vitamin B12 deficiency. Conclusions Vitamin B12 deficiency is prevalent in approximately 1 in 10 of adult individuals with diabetes in Uganda. We recommend screening for vitamin B12 deficiency among diabetic patients in Uganda especially those with low hemoglobin concentrations and glycated hemoglobin levels ≥ 7 %.
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Affiliation(s)
- George Patrick Akabwai
- Department of Medicine, Makerere University College of Health Sciences, P.O.BOX 7062, Kampala, Uganda
| | - Davis Kibirige
- Department of Medicine/Diabetic and Hypertension Clinics, Our Lady of Consolata Hospital Kisubi, Wakiso, Uganda
| | - Levi Mugenyi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Mark Kaddu
- Department of Medicine, Makerere University College of Health Sciences, P.O.BOX 7062, Kampala, Uganda
| | - Christopher Opio
- Department of Medicine, Makerere University College of Health Sciences, P.O.BOX 7062, Kampala, Uganda
| | - Rejani Lalitha
- Department of Medicine, Makerere University College of Health Sciences, P.O.BOX 7062, Kampala, Uganda
| | - Edrisa Mutebi
- Diabetes/Endocrine Unit, Mulago National Referral and Teaching Hospital, Kampala, Uganda
| | - Martha Sajatovic
- Department of Neurology, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, OH USA
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