Associations of social support, depressive symptoms, and cognitive function among dementia-free older adults: A population-based study.

INTRODUCTION

We sought to examine the cross-sectional associations of social support and depressive symptoms with cognitive function in dementia-free rural older adults.

METHODS

This population-based cross-sectional study included 4719 participants (age ≥ 60 years) living in rural China. Social support and depressive symptoms were measured using the Social Support Rating Scale and the 15-item Geriatric Depression Scale, respectively. Global cognition, memory, verbal fluency, attention, and executive function were assessed using a neuropsychological test battery. Mild cognitive impairment (MCI) was defined following Petersen's criteria. Data were analyzed using general linear and logistic regression models.

RESULTS

Greater social support was associated with lower likelihood of MCI and greater z-scores of global cognition, memory, verbal fluency, and executive function (all P < 0.05). Having depressive symptoms was associated with increased likelihood of MCI and lower z-scores of global cognition, memory, verbal fluency, attention, and executive function (all P < 0.05). Greater social support was associated with higher global cognitive z-score in men, higher memory z-score in APOE ε4 non-carriers, and higher executive function z-score in participants with school education (all P < 0.01). The association of depressive symptoms with lower z-scores of global cognition and attention was stronger among people with formal schooling than those without (P < 0.01). Furthermore, depressive symptoms could significantly mediate 46.97 % of the cross-sectional association between social support and global cognition.

CONCLUSION

Late-life social support and having no depressive symptoms are associated with a reduced likelihood of MCI and better cognitive function in a rural Chinese older population, with the associations varying by sex, education, and APOE genotype.