Incidence of dementia in a population cohort of older people from São Paulo, Brazil

• Published in: International journal of geriatric psychiatry Vol. 37; no. 2
• Main Authors: Lopes, Marcos Antonio, Nassar, Silvia Modesto, Barcelos‐Ferreira, Ricardo, Folquitto, Jefferson Cunha, Litvoc, Júlio
• Format: Journal Article
• Language: English
• Published: England 01.02.2022
• Subjects: Aged; Alzheimer Disease - epidemiology; Brazil - epidemiology; Cohort Studies; dementia; Dementia - diagnosis; Dementia - epidemiology; developing countries; epidemiology; Female; Humans; Incidence; longitudinal studies; Male; Prospective Studies; Risk Factors; Brazil; epidemiology; dementia; developing countries; incidence; longitudinal studies
• ISSN: 0885-6230; 1099-1166
• DOI: 10.1002/gps.5660

Objectives To estimate the incidence of dementia in a community‐dwelling older population from São Paulo city, Brazil. Methods/Design This two‐phase prospective cohort study evaluated a representative cluster sample of 1370 individuals aged 60 years old and over from three different socioeconomic levels. The community screening phase consisted of a tested combination of cognitive and functional tests administered among the subjects and informants. In the hospital diagnosis phase, the Cambridge Examination was performed; the diagnosis of dementia and dementia subtypes was made according to DSM IV criteria. Incidence rates were expressed in person‐years, multiplied by 1000. The risk of developing dementia was calculated using Cox regression. Results Among 1370 eligible subjects, 678 were accessed, and 489 completed the evaluation. Forty‐two subjects were diagnosed with dementia. The incidence rate of dementia and Alzheimer's disease (AD) were 11.2 (95% CI: 8.0–15.1) and 8.9 (95% CI: 6.1–12.5) per 1000 person‐years, respectively; there were high age‐specific rates of dementia among younger individuals. There was a trend of a higher risk of developing AD for women than for men. Multivariate analysis showed that older age, the presence of diabetes and the presence of amnestic MCI increased the risk of developing dementia. Conclusions The age‐specific rates in younger individuals were expressively higher than in worldwide studies and supposedly affected by cardiovascular morbidity. The higher risk in women in a younger sample corroborated the interaction between sex and AD. The increased risk of amnestic MCI reinforced its contribution to the progression to dementia and AD. Key points The contribution of this study was to enhance the knowledge about epidemiology of dementia, by exploring longitudinal data from the continental region with the highest global prevalence rates, assessed at an environment of high sociodemographic diversity in the largest city of Brazil, São Paulo. Among younger people, dementia rates were higher than the global incidence rates. People with amnestic MCI and diabetes were at greater risk for developing dementia, and women for developing Alzheimer's disease. Cardiovascular morbidity, early onset of symptoms and sex‐specific interaction in a younger sample were highlighted in the occurrence of dementia.