Objectives: To determine the relationships between Chlamydia pneumoniae infection, carotid atherosclerosis, and dyslipidemia in patients with vascular dementia (VaD) and Alzheimer's disease (AD).
Design: Case control study.
Setting: Showa University Karasuyama Hospital, Tokyo, Japan.
Participants: One hundred twenty-four elderly subjects: 31 with VaD, 61 with AD, and 32 age-matched controls without dementia.
Measurements: Presence of antibodies to C. pneumoniae (immunoglobulin G (IgG) and IgA), the serum concentrations of high-sensitive C-reactive protein (hs-CRP) and atherogenic lipoproteins, and the carotid artery intima-media thickness (IMT) and plaques were determined.
Results: Age; body mass index; systolic and diastolic blood pressures; and fasting plasma glucose, hemoglobin A(1c), high-density lipoprotein cholesterol, and apolipoprotein A-I, B, and E concentrations did not differ significantly between the three groups, but the mean IMT and frequency of atherosclerotic plaques in the carotid arteries, as well as the serum concentrations of low-density lipoprotein cholesterol (LDL-C), lipoprotein(a), and lipid peroxides were significantly greater in VaD patients than in AD patients or nondemented controls. Hs-CRP concentrations and prevalence of C. pneumoniae IgG and IgA antibodies also were significantly higher in VaD patients than in AD patients and nondemented controls. Multiple logistic regression analysis revealed that carotid IMT and plaques, LDL-C, lipid peroxides, hs-CRP, and IgG and IgA C. pneumoniae seropositivity were independent risk factors for VaD.
Conclusion: These results suggest that carotid atherosclerosis, atherogenic lipoproteins, and C. pneumoniae infection (as documented by the IgG and IgA seropositivity together with increased hs-CRP) may be VaD risk factors.