Lifestyle, Psychosocial and Demographic Correlates of Objective Cognitive Performance in Middle-Aged and Older Adults with Subjective Cognitive Complaints: A Cross-Sectional Baseline Analysis of the N-HANCE Cohort

Background: Subjective cognitive complaints (SCCs) in middle-aged and older adults are recognized as early warning signs of future cognitive decline. While biological risk factors have been studied extensively, less is known about how modifiable lifestyle factors, stress, mood and sleep relate to actual performance on cognitive tests. Objective: To examine associations between lifestyle (physical activity, alcohol consumption), psychosocial factors (perceived stress, mood, sleep) and standardized cognitive performance in adults with SCCs. Methods: We conducted a cross-sectional analysis using baseline data from 276 adults aged 50–75 years enrolled in the N-HANCE study. Participants completed the Test of Attentional Performance (TAP) and Digit Span (Forward and Backward). Lifestyle and psychosocial variables were assessed using structured questions and validated self-report scales. Associations were examined using Spearman correlations and Mann–Whitney U tests, with Benjamini–Hochberg correction applied across the full family of 132 predictor–outcome comparisons, followed by linear regression models adjusted for age, sex and educational attainment. Results: Educational attainment showed the strongest and most consistent associations, relating to better performance across attention and memory measures assessed (ρ = 0.21 to 0.44, all q < 0.01). Older age was associated with poorer memory span and less consistent alertness. A history of depression was associated with reduced alertness and this association was essentially unchanged after adjustment (β = −0.19, p < 0.001). Higher BMI was associated with poorer memory span (ρ = −0.18; adjusted β = −0.16, p = 0.005) and higher perceived stress with poorer working memory (Digit Span Backward ρ = −0.21; adjusted β = −0.11, p = 0.046; p = 0.062 under robust standard errors). Associations involving mood and sleep quality attenuated to non-significance after adjustment, while physical activity retained only a marginal association with divided attention. Nineteen of 132 associations survived correction for multiple comparisons. Conclusions: In adults with SCCs, educational attainment and age, a proxy of cognitive reserve and an index of aging respectively, rather than modifiable targets, accounted for the strongest associations with objective cognitive performance. Among potentially modifiable factors, a history of depression and higher BMI showed the most robust independent associations, while associations with mood and sleep did not persist after adjustment and physical activity retained only a marginal association. These cross-sectional findings identify candidate risk and resilience markers that require confirmation in longitudinal follow-up.