Relationship between vitamin B12 and sensory and motor peripheral nerve function in older adults

J Am Geriatr Soc. 2012 Jun;60(6):1057-63. doi: 10.1111/j.1532-5415.2012.03998.x.

Abstract

Objectives: To examine whether deficient B12 status or low serum B12 levels are associated with worse sensory and motor peripheral nerve function in older adults.

Design: Cross-sectional.

Setting: Health, Aging and Body Composition Study.

Participants: Two thousand two hundred and eighty-seven adults aged 72 to 83 (mean 76.5 ± 2.9; 51.4% female; 38.3% black).

Measurements: Low serum B12 was defined as serum B12 less than 260 pmol/L, and deficient B12 status was defined as B12 less than 260 pmol/L, methylmalonic acid (MMA) greater than 271 nmol/L, and MMA greater than 2-methylcitrate. Peripheral nerve function was assessed according to peroneal nerve conduction amplitude and velocity (NCV) (motor), 1.4 g/10 g monofilament detection, average vibration threshold detection, and peripheral neuropathy symptoms (numbness, aching or burning pain, or both) (sensory).

Results: B12-deficient status was found in 7.0% of participants, and an additional 10.1% had low serum B12 levels. B12 deficient status was associated with greater insensitivity to light (1.4 g) touch (odds ratio = 1.50, 95% confidence interval = 1.06-2.13) and worse NCV (42.3 vs 43.5 m/s) (β = -1.16, P = .01) after multivariable adjustment for demographics, lifestyle factors, and health conditions. Associations were consistent for the alternative definition using low serum B12 only. No significant associations were found for deficient B12 status or the alternative low serum B12 definition and vibration detection, nerve conduction amplitude, or peripheral neuropathy symptoms.

Conclusion: Poor B12 (deficient B12 status and low serum B12) is associated with worse sensory and motor peripheral nerve function. Nerve function impairments may lead to physical function declines and disability in older adults, suggesting that prevention and treatment of low B12 levels may be important to evaluate.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • African Continental Ancestry Group
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Chi-Square Distribution
  • Cross-Sectional Studies
  • European Continental Ancestry Group
  • Female
  • Humans
  • Male
  • Pennsylvania
  • Peripheral Nervous System Diseases / blood*
  • Peripheral Nervous System Diseases / ethnology
  • Peripheral Nervous System Diseases / etiology*
  • Prospective Studies
  • Regression Analysis
  • Surveys and Questionnaires
  • Tennessee
  • Vitamin B 12 Deficiency / blood*
  • Vitamin B 12 Deficiency / complications*
  • Vitamin B 12 Deficiency / ethnology