Sex differences in the relation between subjective memory complaints, impairments in instrumental activities of daily living, and risk of dementia.

Background: Older people with symptoms of subjective memory complaints (SMC) and impairments in instrumental activities of daily living (IADL) have an increased risk of developing dementia. The predictive value of SMC and IADL‐impairments may be modified by sex. This could have consequences for personalized risk prediction and prognosis. Methods: From the Prevention of Dementia by Intensive Vascular care study (preDIVA), 3495 community‐dwelling older people, aged 70‐78 years (mean=74.3±2.5) without dementia, were investigated over a median follow‐up of 6.7 years. SMC at baseline were assessed using the memory question from the 15‐item Geriatric Depression Scale. IADL‐impairments were assessed using the Academic Medical Center Linear Disability Score (ALDS). Potential sex‐differences in the predictive value of SMC and IADL‐impairments for incident dementia were assessed using Cox regression models with an interaction term for sex*ALDS_SMC. Results: Women with isolated SMC (HR=2.10,95%CI=0.94‐4.69) and SMC combined with IADL‐impairments (HR=2.96,95%CI=1.66‐5.28) were at greater risk of developing dementia than men (HR=1.51,95%CI=0.83‐2.75; HR=1.24,95%CI=0.59‐2.61 respectively), but these differences were not significant (p‐interaction=0.67 and 0.13). Isolated IADL‐impairments were associated with a significantly higher risk of mortality (HR=1.36,95%CI=1.09‐1.68), and a lower risk of dementia (HR=0.70,95%CI=0.48‐1.00). These associations were particularly prominent in men, but were not significantly different compared to women (p‐interaction=0.25 and 0.83). Conclusion: SMC increase dementia risk, especially when occurring together with IADL‐impairments. This relation may be somewhat stronger in women. Isolated IADL‐impairments do not increase dementia risk. Competing mortality risk may strongly influence these associations, especially in men, suggesting it is essential to assess when comparing sex‐differences in dementia risk. [ABSTRACT FROM AUTHOR]