Impact of viral and bacterial burden on cognitive impairment in elderly persons with cardiovascular diseases.
OBJECTIVE
Inflammation and infectious etiology have been implicated in the pathogenesis of dementia. We sought to investigate whether the seropositivity of common infections was associated with cognitive function.


METHODS
Viral burden (seropositivity for herpes simplex virus type 1 [HSV-1], herpes simplex virus type 2 [HSV-2], or cytomegalovirus [CMV]) and bacterial burden (Chlamydia pneumoniae and Mycoplasma pneumoniae) were related to cognitive status and its impairment among 383 home-dwelling elderly with cardiovascular diseases (mean age, 80 years). The Mini-Mental State Examination (MMSE) and its changes and the Clinical Dementia Rating (CDR) were used to define cognitive impairment.


RESULTS
At baseline, 0 to 1, 2, and 3 positive titers toward viruses were found in 48 (12.5%), 229 (59.8%), and 106 individuals (27.7%), respectively. MMSE points decreased with increasing viral burden (P=0.03). At baseline, 58 individuals (15.1%) had cognitive impairment, which after adjustments was significantly associated with seropositivity for 3 viruses (hazard ratio, 2.5; 95% CI, 1.3 to 4.7). MMSE score decreased in 150 (43% of 348) during 12-month follow-up. After adjustment for MMSE score at baseline and with 0 to 1 seropositivities as reference (1.0), the hazard ratios were 1.8 (95% CI, 0.9 to 3.6) and 2.3 (95% CI, 1.1 to 5.0) for 2 and 3 seropositivities, respectively. The prevalence of possible or definite dementia according to CDR also increased with viral burden. No significant associations were observed between bacterial burden and cognition.


CONCLUSIONS
Viral pathogen burden of HSV and CMV was associated with cognitive impairment in home-dwelling elderly persons with cardiovascular diseases. The results need to be tested in larger databases, but they may offer a preventable cause of cognitive decline.
Strandberg
Timo E
TE
Department of Medicine, Geriatric Clinic, University of Helsinki, PO Box 340, FIN-00029 HUS Helsinki, Finland. timo.strandberg@hus.fi
Pitkala
Kaisu H
KH
Linnavuori
Kimmo H
KH
Tilvis
Reijo S
RS
D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001424:Bacterial Infections / Q000175:diagnosis / Q000453:epidemiology*; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003072:Cognition Disorders / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003586:Cytomegalovirus Infections / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D006566:Herpesviridae Infections / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D012042:Registries / Q000706:statistics & numerical data; D016036:Seroepidemiologic Studies; D014777:Virus Diseases / Q000175:diagnosis / Q000453:epidemiology*
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral