Depressive symptoms predict memory decline over subsequent 4 years: longitudinal analysis of the Guangzhou Biobank Cohort Study

Abstract

Introduction Late-life depression may increase dementia risk, raising the possibility of overlapping pathophysiology and potential preventive strategies. We examined whether: a) baseline depressive symptoms predicted memory decline, and b) baseline memory function predicted mood decline, in an older Chinese cohort. Methods We conducted a prospective analysis based on the Guangzhou Biobank Cohort Study on 30,518 community-dwelling participants aged 50+ years with a mean follow-up period of 4.1 years. In an unselected sub-sample of 5,954 people (mean age 59.5 years, standard deviation 7.1, 75% females), we assessed baseline Geriatric Depression Score (GDS, maximum 15, higher score indicating more depressive symptoms) and a change in the Delayed 10-Word Recall Test score (DWRT, maximum 10 points, higher score indicating better memory) between baseline and follow-up. Conversely, we also assessed DWRT at baseline and a change in GDS between baseline and follow-up. Multivariate hierachichal linear regression was used to assess the association between GDS and DWRT. Model 1 was adjusting for baseline GDS/DWRT, model 2 was adjusting for age, sex, education, occupation, smoking status, alcohol use, physical activity, and body mass index; and model 3 was adjusting for self-rated health and vascular risk factors (hypertension, diabetes and vascular diseases). Results After adjusting for age, sex, education, occupation, smoking status, alcohol use, physical activity and body mass index, for every +1 point increase in baseline GDS, there was a significant -0.01 points (95% CI -0.03 to -0.009, P=0.02) decrease in DWRT over 4 years in model 2. The significance association remained after further adjustment for vascular factors (systolic blood pressure, fasting glucose, low-density lipoprotein cholesterol and BMI, p<.01) in model 3. Similarly, after similar adjustments, baseline DWRT score was significantly associated with worsening in GDS over 4 years (p=0.003 for model 2, and p=0.04 for model 3). Conclusions In this large Chinese cohort, depressive symptoms predicted memory decline over 4 years, and vice versa. Further interventional studies are warranted to clarify the biological and clinical implications of the association, and explore the potential benefits of treating depression in the primary prevention of memory decline.