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Ethnic Differences in Singapore's Dementia Prevalence: The Stroke, Parkinson's Disease, Epilepsy, and Dementia in Singapore Study

Authors

  • Suresh Sahadevan MBBS,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Seang Mei Saw PhD,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Wei Gao PhD,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Louis C.S. Tan MBBS,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Jing Jih Chin MBBS,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Ching ye Hong MBBS,

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Narayanaswamy Venketasubramanian MBBS

    1. From the *Department of General Medicine, Tan Tock Seng Hospital, SingaporeDepartment of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeDepartment of Palliative Care, Policy & Rehabilitation, King's College London, Weston Education Centre, Denmark Hill, London, United Kingdom§Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, SingaporeDepartment of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; and #Strategic Planning Department, Research and Strategic Planning Division, Health Promotion Board, Singapore.
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  • Paper presented at the 5th Asia-Pacific Regional Meeting of the International Working Group on Harmonization of Dementia Drug Guidelines, Manila, Philippines, 2006.

Address correspondence to Dr. Suresh Sahadevan, Department of General Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433. E-mail: suresh_sahadevan@ttsh.com.sg

Abstract

OBJECTIVES: To study the prevalence of dementia in Singapore among Chinese, Malays, and Indians.

DESIGN: A two-phase, cross-sectional study of randomly selected population from central Singapore with disproportionate race stratification.

SETTING: Community-based study. Subjects screened to have cognitive impairment at phase 1 in their homes were evaluated clinically for dementia at phase 2 in nearby community centers.

PARTICIPANTS: Fourteen thousand eight hundred seventeen subjects aged 50 and older (67% participation rate).

MEASUREMENTS: The locally validated Abbreviated Mental Test was used to screen for cognitive impairment at phase 1. Dementia was diagnosed at phase 2 as per Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Possible Alzheimer's disease (AD) and possible vascular dementia (VD) were diagnosed along the National Institute of Neurological and Communicative Disorders—Alzheimer's Disease and Related Disorders Association and National Institute of Neurological Disorders and Stroke—Association Internationale pour la Recherche et l'Enseignement en Neuroscienes criteria, respectively.

RESULTS: The overall age- and race-standardized dementia prevalence was 1.26% (95% confidence interval (CI)=1.10–1.45). Prevalence (in 5-year age bands) was 0.08% (50–54), 0.08% (55–59), 0.44% (60–64), 1.16% (65–69), 1.84% (70–74), 3.26% (75–79), 8.35% (80–84), and 16.42% (≥85). From age 50 to 69, 65% of dementia cases were VD; at older ages, 60% were AD. Logistic regression (adjusted for age, sex, education) showed that Malays had twice the risk for AD as Chinese, and Indians had more than twice the risk for AD and VD than Chinese.

CONCLUSION: Singapore's dementia prevalence, primarily influenced by its Chinese majority, is lower than seen in the West. The striking interethnic differences suggest a need for a dementia incidence study and further investigation of underlying genetic and cultural differences between the three ethnic groups in relation to dementia risk.

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