RETRACTED ARTICLE: Differences in cognitive functions between cytomegalovirus-infected and cytomegalovirus-free university students: a case control study

Veronica Chvatalova,Jaroslav Flegr,Blanka Sebankova,Hana Hrbackova,Petr Turecek

doi:10.1038/s41598-018-23637-3

Veronica Chvatalova, Jaroslav Flegr + Show 3 more

Open Access

https://doi.org/10.1038/s41598-018-23637-3

Copy DOI

Journal: Scientific Reports	Publication Date: Mar 28, 2018
Citations: 6	License type: open-access

Affiliation: Charles University

Abstract

Cytomegalovirus (CMV) is the herpetic virus, which infects 45–100% people worldwide. Many reports suggest that CMV could impair cognitive functions of infected subjects. Here we searched for indices of effects of CMV on infected subjects’ intelligence and knowledge. The Intelligence Structure Test I-S-T 2000 R was used to compare IQ of 148 CMV-infected and 135 CMV-free university students. Infected students expressed higher intelligence. Paradoxically, their IQ decreased with decreasing concentration of anti-CMV antibodies, which can be used, statistically, as a proxy of the time passed from the moment of infection in young subjects when the age of subjects is statistically controlled. The paradox of seemingly higher intelligence of CMV infected subjects could be explained by the presence of the subpopulation of about 5–10% CMV-positive individuals in the population of “CMV-negative students”. These false negative subjects had probably not only the oldest infections and therefore the lowest concentration of anamnestic antibodies, but also the lowest intelligence among the infected students. Prevalence of CMV infection in all countries is very high, approaching sometimes 90%. Therefore, the total impact of CMV on human intelligence may be large.

Highlights

Cytomegalovirus (CMV) is a ubiquitous virus belonging to the Herpesviridae family with high prevalence rates; 45–100% women of reproductive age are infected worldwide[1]
The prevalence of CMV infection fluctuated depending on size of settlements where subjects spent their childhood from 47% to 59%
Verbal knowledge was the only component of intelligence affected in the subsample of women; verbal knowledge, verbal intelligence, crystallized intelligence, and general knowledge were affected in men and in the total sample

Summary

Introduction

Cytomegalovirus (CMV) is a ubiquitous virus belonging to the Herpesviridae family with high prevalence rates; 45–100% women of reproductive age are infected worldwide[1]. In immunocompetent patients, this infection is assumed as asymptomatic; it, causes dramatic complications in immunocompromised subjects. Postnatal acquired CMV infection has been associated with impaired cognition, predominantly in specific populations, i.e., in elderly with cardiovascular disease[9], healthy elderly[10,11], schizophrenics[12,13] and AIDS patients[14]. The main aim of the present study was to search for indices of impaired cognitive functions in university students with anamnestic anti-CMV antibodies. In the double blind study, we searched for possible differences in intelligence between CMV-infected and CMV-free students and for possible correlations between intelligence and concentration of anti-CMV IgG antibodies using standard IQ test, The Intelligence Structure Test I-S-T 2000 R

Objectives

Methods

Results

Discussion

Conclusion