EPIDEMIOLOGY OF COGNITIVE DISORDERS IN THE ELDERLY POPULATION OF GREECE
Background: Understanding the epidemiology of cognitive disorders in a population is the first step towards establishing coherent and cost-effective prevention and management strategies. Relevant data for Greece were scarce and outdated.
Methods: The Hellenic Epidemiological Longitudinal Investigation of Aging and Diet (HELIAD) is an ongoing prospective cohort of 1984 individuals ≥65 years old randomly selected from an urban and a suburban region in Greece. Participants have received full neurological and neuropsychological assessment by a multidisciplinary team on at least two separate visits about 3 years apart. Diagnostic assessment was reached after consensus team meetings, based on established international criteria.
Results: In people ≥65 years old, dementia prevalence was calculated at 5.3% and Mild Cognitive Impairment (MCI) prevalence at 12.4% (age- and sex-standardized values: 7.5% and 13.1% respectively). Dementia incidence was found to be 19.0/1000 person-years and MCI incidence 54.1/1000 person-years (age- and sex-standardized values: 25.4 and 60.0 respectively). Alzheimer’s disease was by far the most common potential underlying etiology, and amnestic MCI was more prevalent than the non-amnestic types. Each additional year of age increased dementia risk by 19.3% and each additional year of education decreased dementia risk by 12.1%. Apolipoprotein E-ε4 (APOE-ε4) homozygous participants were 18 times more likely to be diagnosed with dementia. In participants with MCI at baseline, APOE-ε4 carriage increased dementia risk by 4.5 times. Each additional year of age over 65 raised the risk of novel MCI by 6.2%, while educational attainment of ≤6 years more than doubled the risk for incident MCI. APOE-ε4 carriage resulted in increased risk for MCI by more than 1.7 times.
Conclusion: Epidemiological indices for cognitive disorders in the elderly population of Greece are generally consistent with published data for Europe and North America. In general, advancing age and APOE-ε4 carriage are risk factors for the development of cognitive disorders, while higher educational attainment appears protective.