Association between Cytomegalovirus antibody levels and cognitive functioning in non-elderly adults

Background: Elevated levels of antibodies to Cytomegalovirus (CMV) have been associated with cognitive impairment, but the quantitative relationship between CMV antibody levels and domains of cognitive functioning in younger adults has not been established. Methods: We measured IgG class antibodies to Cytomegalovirus in 521 individuals, mean age 32.8 years. Participants were selected for the absence of psychiatric disorder and of a serious medical condition that could affect brain functioning. Cognitive functioning was measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Wisconsin Card Sorting Test, Trail Making Test part A, and the WAIS III Letter Number Sequencing subtest. Linear regression analyses were used to measure the quantitative association between cognitive scores and Cytomegalovirus IgG antibody level. Logistic regression analyses were used to measure the odds of low cognitive scores and elevated antibody levels defined as an antibody level > = 50^th, 75^th, and 90^th percentile of the group. Results: Higher levels of CMV antibodies were associated with lower performance on RBANS Total (coefficient -1.03, p<.0002), Delayed Memory (coefficient -0.94, p<.001), Visuospatial/ Constructional (coefficient -1.77, p<5×10^-7), and Letter Number Sequencing (coefficient -0.15, p<.03). There was an incremental relationship between the level of CMV antibody elevation and the odds of a low RBANS Total score. The odds of a low total cognitive score were 1.63 (95 ^th % CI 1.01, 2.64; p<.045), 2.22 (95^th % CI 1.33, 3.70; p<.002), and 2.46 (95^th % CI 1.24, 4.86; p<.010) with a CMV antibody level greater than or equal to the 50^th, 75 ^th, and 90^th percentile respectively. Conclusions: Higher levels of Cytomegalovirus antibodies are associated with lower levels of cognitive functioning in nonelderly adults. Methods for the prevention and treatment of CMV infection should be evaluated to determine if they result in an improvement in cognitive functioning in otherwise healthy adults.