Subjective Cognitive Decline Among Middle-Aged and Older Adults in Hong Kong: A Cross-Sectional Study

Background: Subjective cognitive decline (SCD) is a self-reported perception of cognitive deterioration in individuals who are cognitively normal. Cognitive functions keep steady during adulthood up until around age 40; thereafter, individuals are more likely to experience cognitive decline. SCD is viewed as a possible early sign of Alzheimer’s disease and other forms of dementia. Early detection and intervention addressing SCD could delay the onset of mild cognitive impairment and dementia. Several tools have been developed and evaluated for the phenomenon of SCD in different countries; however, limited research findings can be found in Hong Kong.

Objective: To investigate the prevalence of SCD among middle-aged and older adults in Hong Kong and identify the related factors contributing to its occurrence.

Methods: A cross-sectional survey was undertaken from December 2023 to January 2024 to 200 individuals living in Hong Kong aged 50 years or older. The respondents filled out a questionnaire that collected demographic information, including gender, age, education level and health status. They also completed the Subjective Cognitive Decline Questionnaire-21. Descriptive analysis, logistic analysis and factor analysis were conducted in this study.

Results: A total of 200 samples were collected, of which 122 were classified as having SCD, leading to a prevalence rate of 61% that exceeds that of neighbouring countries. SCD was correlated with the self-rated health score. The Cronbach’s alpha was 0.905. The findings demonstrated significant differences in response to patterns between the two scoring groups for all questions. The results of the factor analysis confirmed the reliability of the four-factor structure, reinforcing the strength of the scale.

Conclusion: The study analysed the prevalence of SCD among middle-aged and older adults in Hong Kong as well as explored the relationship between various factors and SCD. The initial insights gained from the questionnaire will inform the future development of more comprehensive and effective solutions to address cognitive decline in older adults in Hong Kong.