Open Access Research

A randomised controlled trial investigating the effect of vitamin B12 supplementation on neurological function in healthy older people: the Older People and Enhanced Neurological function (OPEN) study protocol [ISRCTN54195799]

Alan D Dangour1*, Elizabeth Allen2, Robert Clarke3, Diana Elbourne2, Nicky Fasey4, Astrid E Fletcher5, Louise Letley4, Marcus Richards6, Ken Whyte1, Kerry Mills7 and Ricardo Uauy1

Author affiliations

1 Department of Nutrition and Public Health Intervention Research, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK

2 Department of Medical Statistics, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK

3 Clinical Trial Service Unit, University of Oxford, Oxford, UK

4 Medical Research Council General Practice Research Framework, London, UK

5 Department of Non-Communicable Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK

6 Medical Research Council Unit for Lifelong Health and Ageing, London, UK

7 Department of Clinical Neurophysiology, King's College Hospital, London, UK

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Citation and License

Nutrition Journal 2011, 10:22  doi:10.1186/1475-2891-10-22

Published: 11 March 2011

Abstract

Background

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.

Methods

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.

Conclusions

In view of the high prevalence of vitamin B12 deficiency in later life, the present trial could have considerable significance for public health.