Marion Bachra


The prevalence of cobalamin (Obi) deficiency among older adults is higher than among younger adults, and is estimated to be between 14% and 23%. Persistent Cbl deficiency can cause a variety of neurological deficits. Neurological dysfunction occurs commonly among older adults, raising the research question whether or not there is a relationship between the high prevalence of Cbl deficiency and neurological dysfunction among older adults.

This case-control study enrolled 120 subjects with and without neurological dysfunction through the Faculty Medical Offices' Internal Medicine and Neurology Outpatient Clinics. All subjects received a neurological and cognitive exam. Blood samples were drawn to assess serum Cbl, methylmalonic acid (MMA), and serum total homocysteine (tHcys) levels. To test the hypothesis whether Cbl deficient subjects consumed less crystalline (free) Cbl, Cbl found in fortified foods and supplements, a food frequency questionnaire was designed.

The prevalence of Cbl deficiency was 16.6% among the "true" controls, and 25% among the cases (Odds Ratio = 1.7, 95% confidence interval = 0.54 - 5.1). "True" controls had perfect neurological scores, while other control subjects had reduced vibration sense. Cbl deficiency in older adults was related to low free Cbl intake, not dietary Cbl intake. Subjects who obtained a daily average of 0 and 1.0 meg of free Cbl were most likely to be Cbl deficient (41.5%), while those who obtained 2.0 meg of free Cbl were least likely to be Cbl deficient (13%)(P=.008).

This study was unable to show that older adults with neurological dysfunction are at greater odds of a Cbl deficiency than a control group. Another study is needed to determine whether or not older adults with neurological dysfunction are at greater odds of a Cbl deficiency than a control group without reduced vibration sense. Furthermore, the relationship between reduced vibration sense in older and Cbl deficiency needs to be further investigated. Prophylactic use of Cbl containing supplements among older adults seems prudent. The current RDA of 2 meg for Cbl needs to be reevaluated in terms of crystalline Cbl and protein-bound Cbl requirements in older adults.




Graduate School

First Advisor

Joan Sabaté

Second Advisor

Georgina E. Hodgkin

Third Advisor

James P. Larsen

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Vitamin B 12 Deficiency -- complications; Nervous System Diseases; Aging -- metabolism; Nutritional Requirement -- in old age



Page Count

vii; 124

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website


Loma Linda University. Del E. Webb Memorial Library. University Archives