Prospective study of increased platelet membrane fluidity as a risk factor for Alzheimer's disease: results at 5 years

OBJECTIVE: The primary goal of this study was to evaluate increased platelet membrane fluidity as a putative risk factor for Alzheimer's disease. METHOD: This report describes the initial results of a prospective, longitudinal study of 330 initially asymptomatic, first- degree relatives of probands with Alzheimer's disease. RESULTS: Five incident cases of Alzheimer's disease were detected during the first 1,582 subject-years of the follow-up period. The age-specific incidence of Alzheimer's disease was several-fold higher than corresponding figures that were obtained in two prospective community studies. Most important, both age and increased platelet membrane fluidity made significant independent contributions to the risk of developing Alzheimer's disease. CONCLUSIONS: These results validate age and a family history of Alzheimer's disease as risk factors for this disorder and provide the first prospective evidence of increased platelet membrane fluidity as a biological risk factor for Alzheimer's disease.