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May 1992

Plasma Vitamin B12 Level as a Potential Cofactor in Studies of Human Immunodeficiency Virus Type 1—Related Cognitive Changes

Author Affiliations

From the Department of Epidemiology and Public Health (Drs Beach, Morgan, Mantero-Atienza, Shor-Posner, Lu, and Baum), the Center for the Biopsychosocial Study of AIDS (Drs Beach, Morgan, Wilkie, Mantero-Atienza, Blaney, Shor-Posner, Lu, Eisdorfer, and Baum), and the Division of Neonatology (Dr Beach), Broward General Medical Center, Ft Lauderdale, Fla; and the Department of Psychiatry (Drs Mantero-Atienza, Morgan, Wilkie, Blaney, and Eisdorfer), University of Miami (Fla) School of Medicine.

Arch Neurol. 1992;49(5):501-506. doi:10.1001/archneur.1992.00530290089016

• 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 (<180 pmol/L) performed more poorly than did those with normal (≥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.

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