Midlife Cognition, Vascular Health Predict Dementia and Cognitive Impairment Later in Life
Obesity during midlife was associated with a higher risk for mild cognitive impairment and dementia at the final study visit.
According to results of a study published in Alzheimer's and Dementia, mild cognitive impairment (MCI) and vascular risk factors (eg, body mass index, smoking status, stroke history, hypertension, etc) are independent predictors for dementia later in life.
Investigators reviewed data from patients aged 45 to 64 years who were enrolled in the Atherosclerosis Risk in Communities (ARIC) Study and who attended additional visits for cognitive function evaluation and repeat cardiovascular risk factor assessment. Only participants who had consented to a 20- to 25-year follow-up evaluation for cognitive and cardiovascular risk factors were enrolled (n=5995). The ARIC cognitive battery was used to evaluate cognitive decline at follow-up, and researchers categorized patients with regard to their cognitive status (ie, cognitively normal, MCI, or dementia).
At follow-up, participants with an education beyond high school at the first study visit were significantly less likely to have dementia compared with MCI and a cognitively normal diagnosis (P <.0001). Participants who were carriers for the APOE ε4 allele also had a greater likelihood of dementia compared with MCI at follow-up (P <.0001). In addition, individuals scoring in the lowest quartile of cognitive test scores at the second visit were more likely to be diagnosed with MCI (odds ratio [OR], 5.3; 95% CI, 4.2-6.3) and dementia (OR, 3.8; 95% CI, 2.5-6.0) later in life.
Obesity during midlife was associated with a higher risk for MCI (OR, 1.21; 95% CI, 1.02-1.45) and dementia (OR, 1.36; 95% CI, 1.02-1.81) at the final study visit. The presence of hypertension and diabetes mellitus was also associated with greater odds of MCI (OR, 1.72; 95% CI, 1.32-2.25) and dementia (OR, 1.83; 95% CI, 1.26-2.66) in late life. In addition, patients with coronary heart disease at the initial visit had a greater chance of dementia at follow-up (OR, 1.68; 95% CI, 1.11-2.54).
The researchers were unable to investigate how vascular and cognitive risk factors at initial assessments were able to drive the later-in-life dementia and MCI risks, limiting the findings to associations only.
Despite the lack of causative findings, the investigators believe "that midlife cognition and midlife [vascular risk factors] act on brain mechanisms pertinent to cognition through separate pathways."
Knopman DS, Gottesman RF, Sharrett AR, et al. Midlife vascular risk factors and midlife cognitive status in relation to prevalence of mild cognitive impairment and dementia in later life: The Q7 Atherosclerosis Risk in Communities Study [published online May 12, 2018]. Alzheimer's & Dementia. doi: 10.1016/j.jalz.2018.03.011