Department of Nutrition and Public Health Intervention Research, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.
Nutr J. 2011 Mar 11;10:22. doi: 10.1186/1475-2891-10-22.
Vitamin B12 deficiency is common in older people and the prevalence increases with age. Vitamin B12 deficiency may present as macrocytic anaemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. The diagnosis and indications for treatment are clear for individuals with low plasma levels of vitamin B12 in the setting of megaloblastic anaemia and neuropathy, but the relevance of treatment of vitamin B12 deficiency in the absence of such clinical signs is uncertain.
The aim of the present study is to assess whether dietary supplementation with crystalline vitamin B12 will improve electrophysiological indices of neurological function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of anaemia. To test this hypothesis we designed a randomized double-blind placebo-controlled trial involving 200 older people aged 75 years or greater who were randomly allocated to receive either a daily oral tablet containing 1 mg vitamin B12 or a matching placebo tablet. The primary outcome assessed at 12 months is change in electrophysiological indices of peripheral and central neurosensory responses required for mobility and sensory function. We here report the detailed study protocol.
In view of the high prevalence of vitamin B12 deficiency in later life, the present trial could have considerable significance for public health.
维生素 B12 缺乏在老年人中很常见，且随着年龄的增长而增加。维生素 B12 缺乏可表现为巨幼细胞性贫血、亚急性联合脊髓变性或神经病，但老年人常无症状。在巨幼细胞性贫血和神经病患者中，血浆维生素 B12 水平低的情况下，其诊断和治疗指征明确，但在无此类临床体征的情况下，维生素 B12 缺乏的治疗相关性尚不确定。
本研究旨在评估在无贫血的情况下，有生化证据表明维生素 B12 不足的老年人，补充结晶维生素 B12 是否会改善神经功能的电生理指标。为了验证这一假设，我们设计了一项随机、双盲、安慰剂对照试验，纳入了 200 名年龄在 75 岁及以上的老年人，他们被随机分配接受每日口服 1 毫克维生素 B12 或匹配的安慰剂片。12 个月时的主要结局评估是移动和感觉功能所需的周围和中枢感觉神经反应的电生理指标变化。我们在此报告详细的研究方案。
鉴于老年人维生素 B12 缺乏的高患病率，本试验对公共卫生可能具有重要意义。
