Emmanuel Andrès, MD, Professor of Internal Medicine, Strasbourg University; Head of the Department of Internal Medicine, Diabetes and Metabolic Diseases, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Mustapha Mecili, MD, Clinical Specialist, Department of Internal Medicine, Diabetes and Metabolic Diseases, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Helen Fothergill, MD, Clinical Specialist, Department of Internal Medicine, Diabetes and Metabolic Diseases, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Thomas Vogel, MD, Clinical Specialist, Department of Internal Medicine and Geriatrics, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Laure Federici, MD,Clinical Specialist, Department of Medicine, Hôpitaux de Colmar, Colmar, France.
Jacques Zimmer, MD PhD, Clinical Researcher, Laboratoire d’Immunogénétique-Allergologie, Centre de Recherche Public de la Santé (CRP-Santé) de Luxembourg, Luxembourg.

Cobalamin (vitamin B12) deficiency is particularly common in among older adults, although it is frequently undiagnosed as the clinical presentations may be subtle. However, serious complications do occur, in particular neuropsychiatric and hematological disorders. In older adults, the main causes of cobalamin deficiency are food-cobalamin malabsorption (50–60%) and pernicious anemia (30–40%). Food-cobalamin malabsorption syndrome is a disorder characterized by the inability to release cobalamin from food or its binding proteins. This syndrome is frequently associated with atrophic gastritis, which may be a result of Helicobacter pylori infection, and long-term ingestion of antacids and biguanides. The management of cobalamin deficiency with cobalamin injections is currently well documented, however new routes of cobalamin administration (including via oral and nasal passages) are being studied. Oral cobalamin therapy is of particular interest in the management of food-cobalamin malabsorption syndrome.
Key words: cobalamin, vitamin B12, cobalamin deficiency, food-cobalamin malabsorption, oral cobalamin therapy.

Sudeep S. Gill, MD, FRCP(C), Research Fellow, Division of Geriatric Medicine, University of Toronto and Kunin-Lunenfeld Applied Research Unit, Baycrest Centre for Geriatric Care, Toronto, ON.
Shabbir M.H. Alibhai, MD, MSc, FRCP(C), Staff Physician, Department of Medicine, University Health Network, Toronto, ON.

Folate deficiency is relatively common in older adults. There is now growing interest in the roles played by folate and B vitamins in the metabolism of homocysteine. Recent studies have suggested a link between elevated levels of homocysteine and the risk of Alzheimer disease. In this article, we will focus on the physiology and pathophysiology related to folate and homocysteine metabolism. We have also included a discussion of the laboratory evaluation of these compounds. Finally, we review the evidence supporting the relationships between folate deficiency, hyperhomocysteinemia and the development of dementia.
Key words: folic acid, vitamin B12, deficiency diseases, homocysteine, dementia.

12 Deficiency in the Elderly

Sudeep S. Gill, MD, FRCP(C), Research Fellow, Division of Geriatric Medicine, University of Toronto and Kunin-Lunenfeld Applied Research Unit, Baycrest Centre for Geriatric Care, Toronto, ON.
Shabbir M.H. Alibhai, MD, MSc, FRCP(C), Staff Physician, Department of Medicine, University Health Network, Toronto, ON.

Vitamin B12 deficiency is a common disorder in older adults, but its diagnostic work-up and management can be complex. In this article, we review the metabolic pathways involving vitamin B12 and the various pathologies that can interfere with these pathways. This discussion provides a framework to understand the following section, which outlines an approach to the clinical examination, laboratory evaluation and treatment of subjects with suspected vitamin B12 deficiency.
Key words: vitamin B12, folic acid, deficiency diseases, dementia, aging.