Relationships between plasma beta-amyloid peptide 1-42 and atherosclerotic risk factors in community-based older populations.

Background: Recent studies have suggested that atherosclerosis contributes to the development of dementia of the Alzheimer's type (DAT). Convenient and valid biochemical markers of DAT are needed to control risk factors for this disease. The aims of the present study were thus (1) to determine the distribution of plasma beta-amyloid peptide1-42 (Abeta1-42) levels in an older population and (2) to investigate factors correlating with plasma levels of this amyloid peptide. Our data support the hypothesis that atherosclerosis plays a role in the pathogenesis of DAT.

Methods: 759 Japanese community residents participated in a municipal medical health evaluation; a subset of 280 was selected at random for the measurement of physiological, psychosocial and life-style variables, together with the analysis of blood specimens for cell counts, hematocrit, Abeta1-42, and other biochemical markers.

Results: Log-transformed plasma Abeta1-42 concentrations showed a Gaussian distribution. Quartiles of log10 (Abeta1-42) concentrations correlated significantly with age categories, but not with other sociopsychological and life-style variables. Plasma Abeta1-42 was significantly correlated with systolic and diastolic blood pressure (DBP; r = 0.19, p = 0.002 and r = 0.16, p = 0.007, respectively), pulse pressure (r = 0.13, p = 0.036), total cholesterol (r = 0.15, p = 0.011), log10 (triacyl glycerol) (r = 0.14, p = 0.021), and log10 (hemoglobin A1c) [log10 (HbA1c)] (r = 0.14, p = 0.020). Stepwise multiple regression analysis showed significant independent effects of DBP, and log(10) (HbA1c) on plasma Abeta1-42 concentrations.

Conclusions: Our findings suggest that conventional atherosclerotic risk factors are associated with plasma Abeta1-42 levels. This observation may be important in the detection and prevention of DAT.