Disruptions of rest-activity pattern in individuals aged 75 or older with coexisting frailty and subjective memory complaints

Subjective memory complaints (SMCs) are commonly observed among community-dwelling older adults. This study aimed to investigate the association of sleep and circadian rest-activity rhythm (RAR) in elderly individuals with coexisting frailty or pre-frailty alongside SMC. Participants aged 75 y and older were recruited from community settings in Akita Prefecture. Data collection was conducted between April 2023 and August 2025. RAR parameters were derived from wrist-worn Actiwatch Spectrum Plus devices, worn on the non-dominant wrist for 7 to 14 consecutive days. A total of 95 participants were included in the final analysis and categorized into four groups: robust (n = 36), SMC only (n = 28), SMC plus pre-frailty (n = 27), and SMC plus frailty (n = 4). Multiple logistic regression analyses were performed to examine associations between group status and clinical variables. In the final model, adjusted for age, gender, education, grip strength, Trail Making Test version A (TMT-A), and M10/100, the presence of SMC was significantly associated with higher scores on the Geriatric Depression Scale-15 (GDS-15) (odds ratio [OR] = 1.55; 95% confidence interval [CI]: 1.19-2.03; p = 0.001). Similarly, the SMC coexisting pre-frailty status was significantly associated with GDS-15 scores (OR = 1.73; 95% CI: 1.30-2.31; p = 0.0002), and a significant association was also observed with IV × 100 (OR = 1.04; 95% CI: 1.00-1.09; p = 0.044). The co-occurrence of SMC and pre-frailty appears to be associated with elevated depressive symptoms and fragmented RAR patterns in individuals aged 75 y and older. Further research is warranted to clarify the relationship between disrupted RAR and the combined presence of SMC and frailty.