Subjective short-term memory difficulties at ages 50-75 predict dementia risk in a community-based cohort followed over 17 years.

INTRODUCTION

Subjective cognitive decline (SCD) is an established precursor of dementia. However, the relationship between SCD and dementia has been mostly studied among people aged 65+. We aimed to assess the association between subjective memory difficulties at ages 50-75 with all-cause dementia and dementia-subtypes in a community-based cohort with long-term follow-up.

METHODS

6,190 individuals (51% female) aged 50-75 years (median age, 62) attending a general health examination (by a total of 684 general practitioners) in Saarland, Germany, in 2000-2002 were recruited for a community-based cohort study. Subjective difficulties regarding short-term and long-term memory were assessed at baseline with two simple yes/no questions. Associations with dementia (-subtypes) diagnoses during 17 years of follow-up were estimated by Cox proportional hazards models.

RESULTS

492 participants were diagnosed with dementia during 17 years of follow-up. Participants with short-term memory difficulties were at higher risk to receive incident all-cause dementia and vascular dementia diagnoses both within 0-9 years (age and sex adjusted hazard ratios (aHR), 1.80 and 2.00, respectively) and within 0-17 years (aHR 1.55 and 1.78, respectively) from recruitment (P < 0.05 in all cases). For clinical Alzheimer's disease, a significant association was only seen within the initial 6 years. There were no associations of long-term memory difficulties with any type of dementia.

CONCLUSIONS

Subjective difficulties in short-term memory predict both intermediate and long-term risk of vascular and all-cause dementia even among late middle-age adults. These results underline the importance of cardiovascular disease prevention efforts well before old age for maintaining cognitive health.