Plasma vitamin B12 level as a potential cofactor in studies of human immunodeficiency virus type 1-related cognitive changes
R. S. Beach, R. Morgan, F. Wilkie, E. Mantero-Atienza, N. Blaney, G. Shor-Posner, Y. Lu, C. Eisdorfer and M. K. Baum
Department of Epidemiology and Public Health, Broward General Medical Center, Fort Lauderdale, FL 33136.
Studies of cognitive function in subjects with human immunodeficiency virus
type 1 (HIV-1) infection who remain relatively asymptomatic (ie, Centers
for Disease Control stages II and III) have provided widely variable
estimates of cognitive impairment. In view of the finding that
approximately 25% of asymptomatic HIV-1-infected subjects demonstrate
either marginal or overt vitamin B12 deficiency, we have investigated
plasma vitamin B12 status as a potential cofactor in studies of
HIV-1-related cognitive impairment. When cognition was assessed in
asymptomatic (Centers for Disease Control stages II and III) HIV-1-infected
participants taking into consideration vitamin B12 status, those subjects
with low plasma vitamin B12 levels (less than 180 pmol/L) performed more
poorly than did those with normal (greater than or equal to 180 pmol/L)
vitamin B12 status on specific measures of information processing speed and
visuospatial problem-solving skills. These findings suggest that concurrent
vitamin B12 deficiency may be a cofactor in subtle cognitive changes
observed in the asymptomatic stages of HIV-1 infection. These differences
in prevalence of low plasma vitamin B12 levels may help to explain
differences among studies in the proportion of HIV-1-infected subjects
showing cognitive impairment.
