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Incidence of dementia and major subtypes in a population‐based cohort of older people in São Paulo
Author(s) -
Lopes Marcos A,
Nassar Silvia M,
Litvoc Julio,
Folquitto Jefferson C,
BarcelosFerreira Ricardo,
Filho Geraldo Busatto
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.042777
Subject(s) - dementia , incidence (geometry) , medicine , epidemiology , population , cohort , cohort study , socioeconomic status , gerontology , demography , pediatrics , disease , environmental health , physics , sociology , optics
Background Efforts have been done in order to assess changes over time in dementia occurrence around the world. In developing countries, the scarcity of incidence studies and follow‐up of prevalence studies make the perspective of trends much more imprecise and turn the focus to the primary epidemiological objectives. This study aimed to estimate the incidence of dementia in a community‐dwelling elderly population from São Paulo and its distribution in relation to socio‐demographic and clinical variables and habits. Method A two‐phase design was conducted to a representative cluster sample of individuals aged 60 years old and over from three different socioeconomic levels. The screening‐phase consisted of a tested combination of cognitive and functional tests, applied to the subjects and informants in the community. In the hospital phase, Cambridge Examination, imaging and blood exams were performed; the diagnosis of dementia and dementia subtypes was made according to DSM IV criteria. Incidence rates were calculated dividing the number the dementia cases by the amount of time between the prevalence and incidence studies. Incidence rates were expressed in persons‐year, multiplied by 1000, for dementia and subtypes of dementia. The risk of developing dementia was calculated using Cox regression. Result From 1370 electable subjects, 678 were accessed to evaluation. Forty‐two subjects were diagnosed with dementia. The incidence rate of dementia was 11.22 persons‐years (95%CI: 8.09 – 15.17). The most incident subtype of dementia was Alzheimer’s Disease: 8.90persons‐year (95%CI: 6.13 ‐ 12.51). Multivariate analysis observed that higher ages, presence of diabetes and presence of MCI amnestic increased the risk of developing dementia; age‐adjusted risk was higher in low frequency of playing games and reading books. The risk of developing Alzheimer’s Disease, exclusively, for women compared to men, was nearly three times higher. Conclusion The incidence rate was very close to the other Brazilian study and European, Western and Asian studies. The predominance of Alzheimer’s Disease corroborated the Western studies and probably had a contribution to the higher risk of MCI amnestic in developing dementia. The findings about intellectual habits and female sex should be seen cautiously considering their complexity and the limitations of the present study.