BACKGROUND
Late-life depression (LLD) is associated with increased risk of cognitive decline and dementia, yet clinically relevant neuroimaging markers of short-term cognitive decline remain uncertain.
METHODS
We conducted a two-stage study. In the Shanghai Action to Prevent the Elderly from Dementia (SHAPE) cohort, baseline MRI was compared among 40 LLD participants with stable cognition (LLDcs), 38 LLD participants with cognitive decline over two years (LLDcd), and 47 healthy controls. Measures included peak width of skeletonized mean diffusivity (PSMD), global and tract-specific difference in distribution function based on mean diffusivity (DDFMD), grey-matter measures, and regional diffusion tensor image analysis along the perivascular space (ALPS) indices. Within-group partial correlations between MRI measures and cognitive performance were also examined. Candidate markers were then evaluated in the Sydney Memory and Ageing Study (MAS) LLD sample (21 LLDcs, 16 LLDcd) using SHAPE-trained single-marker Firth logistic models applied without refitting.
RESULTS
In SHAPE, LLDcd showed greater white-matter microstructural burden than LLDcs and controls, including higher PSMD, lower global and tract-specific DDFMD, alongside smaller left nucleus accumbens (L_NAcc) volume. Within LLDcd, poorer white-matter integrity was associated with worse orientation and other cognitive domains. In MAS, global DDFMD and L_NAcc volume were the two markers whose discrimination of LLDcd survived correction for multiple comparisons.
CONCLUSIONS
White-matter microstructural burden and smaller L_NAcc volume may help characterize LLD patients at higher near-term risk of cognitive decline. These findings warrant evaluation in larger longitudinal LLD cohorts.
Chaoyue Guo, Yuan Fang, Qi Qiu et al.· International Psychogeriatri...· 0 citations
BACKGROUND
Neighbourhood environmental features, including green and blue spaces, access to amenities, traffic, and ambient air pollution, may influence mental health in later life. Depression in older adults is associated with morbidity, cognitive decline, and reduced quality of life. While cross-sectional studies have linked environmental features to depressive symptoms, longitudinal evidence remains limited. This study examined longitudinal associations between built and natural neighbourhood characteristics, ambient air pollution, and depressive symptoms in older adults.
METHODS
Participants were 1031 adults aged 70-90 years from the Sydney Memory and Ageing Study, followed for up to 12 years. Depressive symptoms were assessed using a modified 14-item Geriatric Depression Scale. Environmental attributes, including tree canopy, parkland, blue space, built environment indicators, and air pollution (particulate matter (PM)2.5 and nitrogen dioxide (NO2)), were measured within 1 km-radius buffers around geocoded residential addresses. Generalised additive mixed models estimated associations of person-level average exposures and within-person changes over time with depressive symptoms.
RESULTS
Higher average tree canopy cover and an increase in commercial land were associated with lower depression scores. Unexpectedly, higher average proportion of parkland, within-person increases in tree canopy cover and decreases in NO₂ exposure were associated with increased depressive symptoms. Sub-analysis comparing participants who moved with those who remained at their original residence indicated that these unexpected associations were observed only among participants who relocated and subsequently reported more depressive symptoms. Other environmental attributes showed no significant associations in adjusted models.
CONCLUSION
Long-term exposure to greater neighbourhood tree canopy is associated with fewer depressive symptoms. Enhancing tree cover may support mental wellbeing in older populations. Other environmental characteristics appeared less influential over long follow-up periods, and mixed findings highlight the complexity and context-dependence of environmental impacts on late-life depressive symptoms.
S. Reppermund, A. Matison, S. Röhr et al.· Journal of Affective Disorde...· 0 citations
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