Participants were recruited from memory clinics in 2 study sites in Singapore (National University Hospital and Saint Luke’s Hospital). Assessments of participants were performed from August 12, 2010, to July 28, 2015. Four diagnostic categories at baseline were eligible for inclusion in this study:8 (1) No cognitive impairment (NCI): individuals who had no objective cognitive impairment on neuropsychological tests, or functional loss, (2) Cognitive impairment no dementia (CIND) was diagnosed in patients who were impaired in at least one cognitive domain on a neuropsychological test battery without loss of daily functions. (3) Vascular CIND was defined as a history of ischemic stroke within the past 6–24 months and neuroimaging evidence of cerebral infarction, with objective evidence of neuropsychological deficits.9 (4) Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) criteria.

All participants underwent physical, clinical, and neuropsychological assessments and neuroimaging at the National University of Singapore. These assessments were performed annually except for neuroimaging which was offered biennially. Ethics approval for this study was obtained from National Healthcare Group Domain-Specific Review Board. The study was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained, in the preferred language of the participants, by bilingual study coordinators before recruitment. All the data were deidentified before study assessments.

Christopher Chen
National University of Singapore
National University Health System, Singapore, Singapore.

Saima Hilal
National University of Singapore
National University Health System, Singapore, Singapore.

Singapore National Medical Research Council center grants, NMRC/NUHCS/2010, and NMRC/NUHS/2010 [R-184-006-184-511] to Christopher Chen.

Acknowledgment statement for any data distributed by NIAGADS:

Data for this study were prepared, archived, and distributed by the National Institute on Aging Alzheimer's Disease Data Storage Site (NIAGADS) at the University of Pennsylvania (U24-AG041689), funded by the National Institute on Aging.

For investigators using Singapore Longitudinal study of Vascular Cognitive Impairment and Dementia data:

National Medical Research Council center grants under Award numbers ]NMRC/NUHCS/2010] and [NMRC/NUHS/2010] [R-184-006-184-511]. NIHAG052409, titled “ADSP Follow-up in Multi-Ethnic Cohorts via Endophenotypes, Omics & Model Systems”.

Wright AC., et al. Contributions of rare and common variation to early-onset and atypical dementia risk. medRxiv. 2023 Feb 8. doi:10.1101/2023.02.06.23285383.Pubmed Link