Background: It is still a commonly held belief that many of the frequently found low cobalamin (Cbl, vitamin B12) levels in older people do not represent deficiency and are therefore without clinical significance and should not be treated. In this study this notion will be challenged.
Methods: In this prospective observational cohort design we studied 28 patients aged 65 years and older with low plasma Cbl (< or =150 pmol/l). A number of haematological (Hb, MCV, five- and six-lobed granulocytes), metabolic (plasma levels of methylmalonic acid and homocysteine), and gastrointestinal (plasma pepsinogen A and C and protein-bound and free Cbl absorption) parameters, and the response to Cbl treatment, were measured. Cbl deficiency was considered to be present when at least one of the following three criteria was fulfilled: (1) haematological or metabolic abnormalities compatible with Cbl deficiency; (2) Cbl malabsorption or atrophic gastritis; (3) a response to Cbl supplementation.
Results: Haematological or metabolic abnormalities were identified in 27 patients. Atrophic gastritis and Cbl malabsorption were identified in, respectively, 15 and 23 patients. Each treated patient showed a haematological or metabolic response to Cbl supplementation. All patients were considered Cbl deficient: 18 patients (64%) fulfilled three criteria of Cbl deficiency, eight (29%) fulfilled two criteria and two (7%) fulfilled one criterion.
Conclusions: According to the generally accepted and a wide variety of criteria, we found that older patients with low Cbl levels were cobalamin deficient. Therefore, these patients should receive Cbl supplementation.