Vitamin B-12 status and neurologic function in older people: a cross-sectional analysis of baseline trial data from the Older People and Enhanced Neurological Function (OPEN) study

Am J Clin Nutr. 2016 Sep;104(3):790-6. doi: 10.3945/ajcn.116.137927. Epub 2016 Aug 17.

Abstract

Background: Aging is associated with a progressive decline in vitamin B-12 status. Overt vitamin B-12 deficiency causes neurologic disturbances in peripheral and central motor and sensory systems, but the public health impact for neurologic disease of moderately low vitamin B-12 status in older people is unclear. Evidence from observational studies is limited by heterogeneity in the definition of vitamin B-12 status and imprecise measures of nerve function.

Objective: We aimed to determine whether vitamin B-12 status is associated with electrophysiologic indexes of peripheral or central neurologic function in asymptomatic older people with moderately low vitamin B-12 status.

Design: We used a cross-sectional analysis of baseline data from the Older People and Enhanced Neurological Function study conducted in Southeast England. This trial investigated the effectiveness of vitamin B-12 supplementation on electrophysiologic indexes of neurologic function in asymptomatic older people (mean age: 80 y) with moderately low vitamin B-12 status (serum vitamin B-12 concentrations ≥107 and <210 pmol/L without anemia, n = 201). Vitamin B-12 status was assessed with the use of total vitamin B-12, holotranscobalamin, and a composite indicator of vitamin B-12 status (cB-12). Electrophysiologic measures of sensory and motor components of peripheral and central nerve function were assessed in all participants by a single observer.

Results: In multivariate models, there was no evidence of an association of vitamin B-12, holotranscobalamin, or cB-12 with any nerve conduction outcome. There was also no evidence of an association of vitamin B-12 status with clinical markers of neurologic function.

Conclusion: This secondary analysis of high-quality trial data did not show any association of any measure of vitamin B-12 status with either peripheral or central neurologic function or any clinical markers of neurologic function in older people with moderately low vitamin B-12 status. The results of this study are unlikely to be generalizable to a less healthy older population with more severe vitamin B-12 deficiency. This trial was registered at www.controlled-trials.com as ISRCTN54195799.

Keywords: central nerve conduction; neurologic; older people; peripheral conduction; vitamin B-12.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Asymptomatic Diseases* / epidemiology
  • Biomarkers / blood
  • Central Nervous System Diseases / diagnosis
  • Central Nervous System Diseases / epidemiology
  • Central Nervous System Diseases / etiology*
  • Central Nervous System Diseases / prevention & control
  • Confounding Factors, Epidemiologic
  • Cross-Sectional Studies
  • Dietary Supplements
  • Double-Blind Method
  • Elder Nutritional Physiological Phenomena*
  • Electrophysiological Phenomena
  • England / epidemiology
  • Female
  • Geriatric Assessment
  • Humans
  • Male
  • Multivariate Analysis
  • Neural Conduction
  • Neurologic Examination
  • Nutritional Status*
  • Peripheral Nervous System Diseases / diagnosis
  • Peripheral Nervous System Diseases / epidemiology
  • Peripheral Nervous System Diseases / etiology*
  • Peripheral Nervous System Diseases / prevention & control
  • Severity of Illness Index
  • Vitamin B 12 / therapeutic use
  • Vitamin B 12 Deficiency / blood
  • Vitamin B 12 Deficiency / diet therapy
  • Vitamin B 12 Deficiency / epidemiology
  • Vitamin B 12 Deficiency / physiopathology*

Substances

  • Biomarkers
  • Vitamin B 12