Almost 1 in 5 community-dwelling elderly in HK have cognitive impairment or dementia

Cognitive impairment or dementia is present in 18.7 percent of community-dwelling older adults in Hong Kong – a prevalence higher than rates reported in previous research – according to a cross-sectional study.

The elderly population in Hong Kong is expected to reach 31 percent by 2039. [www.primaryhealthcare.gov.hk/bp/en/blueprint-2] “Dementia is a leading cause of morbidity and disability for individuals aged ≥65 years. However, there were limited studies on the prevalence of dementia in Hong Kong, particularly in community-dwelling older adults,” wrote the researchers.

To estimate the prevalence of cognitive impairment or dementia in Hong Kong, the researchers interviewed 241 community-dwelling older adults (age, ≥65 years; female, 61 percent) in community centres using the Cantonese version of the structured Mini-Mental State Examination (CMMSE) questionnaire, with a cut-off score of ≤20 indicating cognitive impairment or dementia. [Brain Behav 2025;15:e70388; J.H.K.C. Psych 1994;1: 25-28]

The overall prevalence of cognitive impairment/dementia was 18.7 percent (n=45/241), which was higher than prevalence rates reported in two previous Hong Kong studies in 2019 (9.3 percent) and 2016 (14 percent). [Brain Behav 2025;15:e70388; Int J Environ Res Public Health 2019;16:128; Clin Exp Nephrol 2016;20:126-133]

The highest prevalence was in those aged >80 years (33 percent). Additionally, higher prevalence was found in females than males (20.4 vs 16.0 percent) and in respondents with lower vs higher education levels (22.5 vs 13.6 percent).

“[Of note,] most of the respondents had low dementia literacy, which may explain the potential underdiagnosis of cognitive impairment or dementia in the community,” noted the researchers.

“After the interview, some respondents expressed concern that they might not be able to have follow-up cognitive evaluation due to the long waiting time for appointment bookings for diagnostic services in public hospitals,” they added.

In line with the 12 modifiable risk factors for dementia identified in The 2020 Report of the Lancet Commission, multivariate logistic regression in the current study showed that both depression and hypertension were significant risk factors. Additionally, the current study identified a new risk factor: lower socioeconomic status, as indicated by receipt of Comprehensive Social Security Assistance. [Lancet 2020;396:413-446; Brain Behav 2025;15:e70388]

“The findings emphasized the importance of raising awareness and enhancing screening for cognitive impairment or dementia,” suggested the researchers.  “Identifying associated risk factors is essential for formulating effective public health strategies for preventing dementia in the community.”

The current study has several limitations, including a small sample size, self-report bias, and selection bias resulting from the inability to conduct random sampling. Moreover, a cross-sectional study design cannot establish causal relationships between the risk factors and cognitive impairment or dementia. Further longitudinal studies could provide more insights into these associations.