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


METHODS
Cross-sectional.


METHODS
Health, Aging and Body Composition Study.


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


METHODS
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.


CONCLUSIONS
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.
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Kira
K
Leishear
Robert M
RM
Boudreau
Stephanie A
SA
Studenski
Luigi
L
Ferrucci
Caterina
C
Rosano
Nathalie
N
de Rekeneire
Denise K
DK
Houston
Stephen B
SB
Kritchevsky
Ann V
AV
Schwartz
Aaron I
AI
Vinik
Eva
E
Hogervorst
Kristine
K
Yaffe
Tamara B
TB
Harris
Anne B
AB
Newman
Elsa S
ES
Strotmeyer
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D044383:Black People; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010414:Pennsylvania; D010523:Peripheral Nervous System Diseases / Q000097:blood* / Q000208:ethnology / Q000209:etiology*; D011446:Prospective Studies; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D013714:Tennessee; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000150:complications* / Q000208:ethnology; D044465:White People; D001741:Black or African American