Vitamin D supplementation and the prevention of fractures and falls.

Vitamin B12 deficiency is common in older people and is associated with cognitive impairment in the absence of anaemia or macrocytosis [1–3]. The prevalence of vitamin B12 deficiency increases in the elderly, mainly due to malabsorption of food-bound vitamin B12 due to atrophic gastritis that limits the ability of older people to release vitamin B12 from dietary sources in meat, fish and dairy products. In reply to Dr Vargese, there was no association between alcohol consumption and vitamin B12 status in the Banbury B12 population study [1]. Thyroid function was not measured in our population study and so we cannot speculate on any such association. [1]. However, the important finding of the Banbury B12 study was that almost all cases of undiagnosed vitamin B12 deficiency did not have anaemia or macrocytosis. The high prevalence of undiagnosed vitamin B12 deficiency is relevant to clinical practice and suggests that it would be prudent to measure vitamin B12 or holotranscobalamin, the metabolically active fraction of vitamin B12, in older people presenting with symptoms suggestive of dementia or cognitive impairment. Correction of established vitamin B12 deficiency in the early stages is appropriate, particularly among those with relevant symptoms. Nevertheless, it is unclear if correction of vitamin B12 deficiency could attenuate the rate of cognitive decline in older people. Randomised evidence for the effects of 3 to 7 years of treatment with B vitamins on cognitive function should be available from ongoing trials of B vitamin supplementation for the prevention of cardiovascular disease in due course. The results of these trials are required before making any recommendation on the use of B-vitamins in patients with established cardiovascular disease for the prevention of dementia. Further large-scale randomised evidence of vitamin B12 supplementation for the maintenance of cognitive function is required in older people in the absence of cardiovascular disease or dementia [4].