Incidence and subtypes of dementia in three elderly populations of central Spain

• Published in: Journal of the neurological sciences 2008-01, Vol.264 (1), p.63-72
• Main Authors: Bermejo-Pareja, F, Benito-León, J, Vega, S, Medrano, M.J, Román, G.C
• Format: Article
• Language: English
• Subjects: Age Distribution; Aged; Aged, 80 and over; Aging - pathology; Alzheimer Disease - diagnosis; Alzheimer Disease - epidemiology; Biological and medical sciences; Cerebrovascular Disorders - epidemiology; Cohort Studies; Comorbidity; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dementia; Dementia - classification; Dementia - diagnosis; Dementia - epidemiology; Dementia, Vascular - diagnosis; Dementia, Vascular - epidemiology; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Educational Status; Epidemiology; Female; Humans; Incidence; Lewy Body Disease - diagnosis; Lewy Body Disease - epidemiology; Male; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Population-based studies; Risk Factors; Sex Distribution; Spain - epidemiology; Stroke - epidemiology; Surveys and Questionnaires
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/j.jns.2007.07.021

Abstract Objective To assess age-, gender, and subtype-specific incidence rates of dementia in three populations in central Spain using data from the Neurological Disorders in Central Spain (NEDICES), a population-based survey of elderly participants. Methods Individuals were evaluated at baseline (1994–1995) and at follow-up (a median of 3.2 years later in 1997–1998). The evaluation included a screening questionnaire for dementia and a neurological assessment, when possible. Results Of 5278 participants evaluated at baseline, there were 306 prevalent dementia cases. One hundred and sixty-one incident dementia cases were identified among 3,891 individuals assessed at follow-up. The large majority had Alzheimer's disease (AD): 115 (71.4%) AD, 18 (11.2%) vascular dementia (VaD), 11 (6.8%) dementia associated with parkinsonism, 11 (6.8%) undetermined etiology, and 6 (3.7%) secondary dementia. Average annual incidence rates (per 1,000 person-years) in the population aged 65 to 90 and over years, adjusted to the standard European population, were 10.6 (95% CI, 8.9 to 12.3) for dementia, 7.4 (95% CI = 6.0 to 8.8) for AD, and 1.4 (95% CI = 0.6 to 2.3) for VaD. Age-specific incidence rates of dementia and AD increased exponentially with advancing age. Age, stroke and illiteracy were independent risk factors for dementia and AD. Aggregation of vascular risk factors was related to a higher risk of both VaD and AD. Conclusions In the NEDICES study, incidence of dementia increased with age beyond age 85 and AD was the most frequent type of dementia. The risk of AD and VaD increased with the number of vascular risk factors.