Age and sex differences in cognitive performance in people with subjective cognitive decline and associated worry: Findings from the Canadian Longitudinal Study on Aging

Subjective cognitive decline (SCD) refers to self-perceived decline in cognition in the absence of objective impairment and may represent a preclinical stage of Alzheimer's disease, particularly when accompanied by worry. However, limited research has examined the influence of age and sex on cognitive performance among individuals with SCD. This study investigated age- and sex-specific associations between SCD (+/- worry) and cross-sectional cognition in the Canadian Longitudinal Study on Aging (CLSA). Participants were categorized into Controls (n = 5713), SCD-No Worry (n = 3379) and SCD + Worry (n = 3511). Analyses were stratified by age (45-54, 55-64, 65-74, 75+) and sex and adjusted for education and depressive symptoms. Cognitive outcomes included four executive function and two verbal memory measures. Regarding executive function, men with SCD + Worry outperformed controls on letter fluency in the 55-64 and 65-74 groups, and women in both SCD groups outperformed controls on letter fluency in the 65-74 group. In contrast, men aged 75+ with SCD + Worry performed worse than controls on semantic fluency. No group differences emerged on Stroop Interference or the mental alternation task. For memory, men aged 45-54 and 55-64 with SCD-No Worry had higher immediate recall, whereas in the 75+ group, lower delayed recall was observed in men with SCD (+/- worry) and women with SCD-No Worry compared to controls. Overall, the results indicate that the clinical relevance of SCD may increase with age, independent of sex and worry status. These findings may improve the clinical utility of SCD and inform earlier detection of individuals at risk of future cognitive decline.