Examining the Relationships Between Cognitive Function and Physical and Mental Health: Interim Findings from HKMMSOP

Background Population ageing is associated with an increase in the number of persons with dementia, which constitutes a significant public health issue. The Hong Kong Mental Morbidity Survey for Older People (HKMMSOP) was carried out to evaluate the local prevalence of dementia and the factors that modulated the disease development. Method Participants aged 60 or over, stratified with age groups, were recruited through random sampling of residential addresses in Hong Kong. They underwent an assessment of their cognitive function (Montreal Cognitive Assessment, MoCA; Clinical Dementia Rating, CDR), physical health (Cumulative Illness Rating Scale, CIRS) and mental health (Clinical Interview Schedule‐Revised, CIS‐R; Short Warwick‐Edinburgh Mental Wellbeing Scale, SWEMWBS). Associative factors of neurocognitive disorders were determined by multinomial regression, with neurocognitive disorders as dependent variables. Result In this interim analysis, 4369 participants of HKMMSOP were included. Their mean age was 69.6, and there was a slight female preponderance (56.3%). On average, they received 8.8 years of education, and their mean MoCA score was 23.8 (SD 4.9). Using CDR, 71.8% were evaluated as having normal cognition, 23.1% with a mild neurocognitive disorder (ND), and 5.2% with a major ND. Older or less educated participants had a higher risk of developing mild and major ND (p<0.001). But the relationships between cognition and physical and mental health differed in the mild and major ND groups. Among those with mild ND, a higher CIRS total score (p<0.001), a higher CIS‐R total score (p<0.001) and a lower SWEMWBS score (p = 0.002) were significantly associated with CDR. However, only CIRS total score (p = 0.004) and SWEMWBS score (p<0.001) remained significant in the major ND group. Conclusion Poorer physical and mental health and lower mental well‐being and life satisfaction were associated with an increased risk of mild ND. But as the disease progressed, lower mental well‐being and life satisfaction and poorer physical health remained significant factors. On the contrary, a higher level of mental symptoms, as exemplified by CIS‐R, was not significantly associated with major ND. It sheds some light on the factors that may modulate the course of the disease and appropriate preventive measures.