Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. Screening average-risk adults for vitamin B12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, use of metformin for more than four months, use of proton pump inhibitors or histamine H2 blockers for more than 12 months, vegans or strict vegetarians, and adults older than 75 years. Initial laboratory assessment should include a complete blood count and serum vitamin B12 level. Measurement of serum methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low-normal levels of vitamin B12. Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms. Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms. Absorption rates improve with supplementation; therefore, patients older than 50 years and vegans or strict vegetarians should consume foods fortified with vitamin B12 or take vitamin B12 supplements. Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely. Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline.

Robert Langan

Andrew J Goodbred

American Family Physician

AMERICAN FAMILY PHYSICIAN 是美国家庭医生学会的半月刊，编辑独立，同行评审期刊。 AFP 的主要目标是为超过 190,000 名家庭医生和其他初级保健临床医生提供高质量的继续医学教育。编辑更喜欢来自经验丰富的临床医生的原创文章，他们撰写简洁、循证、权威的临床评论，有助于家庭医生进行患者护理。法新社只考虑原创的手稿，以前没有发表过，也没有考虑在其他地方发表。展示家庭医学观点和处理常见临床状况的文章是特别可取的。

American Family Physician is a bi-monthly journal published by the American Academy of Family Physicians, with independent editorial oversight and peer review. The primary aim of the journal is to provide high-quality continuing medical education to over 190,000 family physicians and other primary care clinicians. The editors prefer original articles from experienced clinicians that are concise, evidence-based, and authoritative, assisting family physicians in patient care. The journal only considers original manuscripts that have not been previously published and does not entertain submissions that are under consideration elsewhere. Articles that present perspectives on family medicine and address common clinical conditions are particularly welcome.

《American Family Physician》是美国家庭医生学会的半月刊，编辑独立，经过同行评审。该期刊的主要目标是为超过190,000名家庭医生和其他初级保健临床医生提供高质量的继续医学教育。编辑更倾向于接受来自经验丰富的临床医生撰写的原创文章，这些文章应简洁、循证且权威，能够帮助家庭医生进行患者护理。该期刊只考虑原创手稿，且这些手稿之前未曾发表，也不考虑在其他地方发表。特别欢迎展示家庭医学观点和处理常见临床状况的文章。

Vitamin B12 Deficiency: Recognition and Management.

Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and Neurologic symptoms and should be considered in patients with severe deficiency or severe neurologic symptoms.

Category	Quartile
医学	3
医学, 初级卫生保健	2
医学, 医学内科	3

Vitamin B12 Deficiency: Recognition and Management.

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Journal Info

Category	Quartile
PRIMARY HEALTH CARE	1