Vitamin B-12 treatment has limited effect on health-related quality of life among individuals with elevated plasma methylmalonic acid: a randomized placebo-controlled study.

Abstract

OBJECTIVE: To examine the hypothesis that treatment with vitamin B-12 improves health-related quality of life (HRQOL) in individuals with biochemical signs of vitamin B-12 deficiency. DESIGN: A randomized placebo-controlled study. SETTING: Municipality of Aarhus, Denmark. SUBJECTS: Nonhospitalized individuals (n = 140) with a modest increase in plasma methylmalonic acid (0.40-2.00 micromol L-1) not previously treated with vitamin B-12. INTERVENTION: The participants were randomized to vitamin B-12 injection treatment or placebo weekly for 4 weeks and re-examined 3 months later. The investigator and the participants were blinded to the intervention. MAIN OUTCOME MEASURE: Change in HRQOL assessed by the SF-36 questionnaire from baseline to follow-up examination 3 months later. RESULTS: The participants reported a significantly worser HRQOL than the age- and sex-matched Danish general population (P < 0.001). However, no change was observed after treatment with vitamin B-12 for seven of eight health dimensions. A significant improvement was found only in general health when compared with the placebo group (P = 0.03). CONCLUSIONS: Vitamin B-12 treatment influenced only one of eight dimensions of HRQOL amongst participants with biochemical signs of vitamin B-12 deficiency. We therefore question the benefit of vitamin B-12 treatment amongst elderly with a modestly increased plasma methylmalonic acid as the only sign of vitamin B-12 deficiency.