Prevalence of Cognitive Impairment and Dementia in Malays - Epidemiology of Dementia in Singapore Study

Objective: To study the prevalence of cognitive impairment and dementia in communitydwelling Malays from Singapore; and to examine differences in prevalence among Chinese and Malays. Methods: Subjects (≥ 60 years) - drawn from the Malay component of the on-going multiethnic Epidemiology of Dementia in Singapore study - were screened using locally validated Abbreviated Mental Test and Progressive Forgetfulness Questionnaire. Subsequently, screen-positive participants underwent detailed neuropsychological assessments and neuroimaging. Cognitive impairment no dementia (CIND) and dementia were diagnosed based on accepted criteria. Results: A total of 966 Malay subjects were included, of whom 102 had CIND-mild, 135 CINDmoderate, and 27 dementia. The overall age-standardized prevalence of any cognitive impairment was 25.5%, including 2% of dementia. The prevalence of any cognitive impairment increased with age from 14·9% in those aged 60-64 years to 40.2% in age ≥80 years. Women had a higher prevalence of CIND and dementia than men. Compared to previously published data from EDIS on Chinese, Malay were nearly twice more likely to have any cognitive impairment (Odds ratios adjusted for age, demographic and cardiovascular risk factors, and ApoE4 carrier: 2.03, 95% confidence interval: 1.48-2.77). Conclusion: Among elderly Malays, the overall prevalence of any cognitive impairment was 25.5%. Even with a similar protocol of recruitment and assessment and adjusting for known risk factors, the prevalence of cognitive impairment was higher in Malays compared to Chinese. Further research is needed to unravel other factors that may underlie these ethnic differences in the occurrence of cognitive impairment.