Associations between modifiable and non‐modifiable risk factors and domain‐specific cognitive decline over a 17‐year period

Abstract

AbstractBackgroundModifiable risk factors account for 40% of worldwide dementias. However, to what extent different risk factors are associated with different types of cognitive decline remains unclear. The aim of this study was to investigate how different risk factors contribute to future decline in memory and attention/executive function, respectively.MethodBaseline examination of individuals without dementia in the prospective Swedish population‐based Malmö Diet and Cancer Study (MDCS) took place in 1991‐1996. In 2007‐2012, a randomly selected subsample was invited to a re‐examination using cognitive assessments (the Mini‐Mental State Examination [MMSE], A Quick Test of cognitive speed (AQT) and, for a sub‐population, The Montreal Cognitive Assessment (MoCA). Participants with complete data on cognitive assessments, body measurements, education and APOE genotype were included in the study (n = 2,881; n = 720 with MoCA). Linear regression models were used to examine the modifiable risk factors (hypertension, body mass index [BMI], long‐term glucose levels [HbA1c], lipid levels, physical activity and alcohol consumption) and non‐modifiable risk factor (APOE‐genotype). Follow‐up outcomes were 1) AQT‐color/form (processing speed and executive function, higher scores indicating worse function), 2) delayed recall and orientation scores from MMSE (memory function), and 3) subscores from MoCA. All models were adjusted for age, sex, education and time between baseline and cognitive assessments.ResultMedian follow‐up time was 17.3 (inter‐quartile range [IQR] 2.2) years. APOE‐e4 and higher HbA1c levels were independently associated with worse future memory function in a multivariable model (Table 1). Mean arterial blood pressure, obesity, lower HDL‐C, and higher HbA1c levels were independently associated with worse future processing speed/executive function (Table 2). Higher alcohol consumption was associated better performance in executive function (Table 2). Similar results were found using corresponding MoCA subscores (delayed recall and orientation subscores; visuospatial/executive and attention subscores).ConclusionIn this prospective, population‐based, 17‐years follow‐up study, cardiovascular risk factors in mid‐life were associated with future decline in processing speed and executive functions, while an APOE‐e4 genotype was associated with worse memory function. Alcohol consumption in mid‐life was associated with better performance in both cognitive domains. These results suggest that targeting cardiovascular risk factors in interventions may have a greater effect on future executive function than memory.