[Epidemiology and risk factors of Alzheimer's disease]

Alzheimer's disease or dementia of the Alzheimer's type (AD/DAT) is one of the most common dementia conditions and it amounts to over 40-90% of dementia cases among elderly and old patients. Epidemiological studies in this area make a great contribution to the study of the etiology and risk factors of AD/DAT). The collaborative reanalysis of AD/DAT prevalence and incidence in EEC countries ("EURODERM" programme) shows that the overall European age-specific prevalence of AD does not differ greatly. There was an exponential increase in age-specific AD/DAT prevalence was found with age, as evidenced by the studies made in Russia. Sex-specific prevalence and incidence of AD/DAT are unclear since the fact that the condition more often occurs in elderly women than in men of the same age has not been confirmed. The data on risk factors obtained in cohort and case-control studies of AD/DAT have been analyzed. Progress in molecular genetics has identified 3 genes that are responsible for the occurrence of familial forms of the disease. The gene of apolipoprotein E on chromosome 19 is recognized to be the major genetic risk factor of late AD/DAT. The role of gene mutations in the trigger mechanisms of sporadic BA/DAT is also discussed. The environmental risk factors of AD/DAT include brain injury, viral infections, neutroxic chemicals, various immunological and hormonal disorders. The protective role of such factors as long-term use of nonsteroid antiinflammatory agents and estrogens is discussed. The involvement of nicotine dependence in the pathogenesis and the role of smoking as a possible protective factor are the subject of discussion. Such factors as education levels, occupation, stresses are widely discussed, although their role is considered to be controversial. The Russian study revealed the influence of chronic stress on AD development. The authors consider that chronic stress may play an important role in AD/DAT progression.