Protocol Summary

Vitamin B12 deficiency is common in older people and treatment is remarkably effective for prevention of associated neurological disease. Vitamin B12 deficiency may present as macrocytic anaemia or as neuropathy, but is not infrequently asymptomatic in older people. The diagnosis is clear in individuals with low plasma levels of vitamin B12 in the setting of megaloblastic anaemia and neuropathy, but difficulties arise in the absence of anaemia or macrocytosis in whom the relevance of treatment is less certain.

The aim of the present study is to assess whether increased dietary intake of crystalline vitamin B12 will improve electrophysiological indices of neurological function and cognitive function, in older people with biochemical evidence of vitamin B12 deficiency in the absence of anaemia. To test this hypothesis, a randomized double-blind placebo-controlled trial will be conducted on 200 older people aged 75 years or greater who will be randomly allocated to receive a daily oral tablet containing either 1mg vitamin B12 or an identical placebo tablet. The primary outcome assessed at 12 months will be change in electrophysiological indices of peripheral and central neurosensory responses which are crucial for mobility and sensory function. In view of the high prevalence of vitamin B12 deficiency, the present study should have considerable public health and quality of life relevance for older people.

The OPEN study protocol has been published in the Nutrition Journal and the publication is freely available here.