Modifiable Risk Factors and Brain Positron Emission Tomography Measures of Amyloid and Tau in Nondemented Adults with Memory Complaints

Abstract

Objective Exercise and diet impact body composition, but their age-related brain effects are unclear at the molecular imaging level. To address these issues, we determined whether body mass index (BMI), physical activity, and diet relate to brain positron emission tomography (PET) of amyloid plaques and tau tangles using 2-(1-(6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl)ethylidene)malononitrile (FDDNP). Methods Volunteers (n = 44, mean age = 62.6 ± 10.7 years) with subjective memory impairment (n = 24) or mild cognitive impairment (MCI; n = 20) were recruited by soliciting for memory complaints. Levels of physical activity and extent of following a Mediterranean-type diet were self-reported. FDDNP-PET scans assessed plaque/tangle binding in Alzheimer’s disease (AD)-associated regions (frontal, parietal, medial and lateral temporal, posterior cingulate). Mixed models controlling for known covariates examined BMI, physical activity, and diet in relation to FDDNP-PET. Results MCI subjects with above normal BMI (>25) had higher FDDNP-PET binding compared to those with normal BMI (1.11(.03) vs 1.08(.03), ES=1.04, t(35)=3.3, p=.002). Greater physical activity was associated with lower FDDNP-PET binding in MCI subjects (1.07(.03) vs 1.11(.03), ES=1.13, t(35) =−3.1, p=.004) but not in subjects with subjective memory impairment (1.07 (.03) vs 1.07(.03), ES=.02, t(35)=−0.1, p=.9). Healthier diet related to lower FDDNP-PET binding, regardless of cognitive status (1.07(.03) vs 1.09(.02), ES=0.72, t(35)=−2.1, p = .04). Conclusion and Relevance These preliminary findings are consistent with a relationship between risk modifiers and brain plaque/tangle deposition in non-demented individuals and supports maintenance of normal body weight, regular physical activity, and healthy diet adherence to protect the brain during aging.

Mediterranean Diet in Preventing Neurodegenerative Diseases

“…A small, multi-modal study in cognitively normal, middle-aged adults found increased beta-amyloid plaque burden and decreased glucose metabolism in those who adhered to the MD [64]. Similar results were found in a study examining amyloid and tau pathology through PET imaging in older adults with subjective memory complaints and MCI; in this study, greater adherence to the MD was associated with less pathology in both groups [65]. If results can be replicated in larger samples, these data may support using PET imaging markers as outcome measures in clinical trials.…”

Randomized trial on the effects of a combined physical/cognitive training in aged MCI subjects: the Train the Brain study

“…The results showed that lower Aβ burden was found in subjects more engaged in cognitively stimulating activities, particularly during early and middle life. A recent study suggests that greater levels of physical activity in MCI subjects is associated with lower Aβ plaque and tangle deposition, estimated by PET67. Thus, there seems to be a correlation between cognitive/physical activity and Aβ burden.…”

Mediterranean diet adherence and rate of cerebral Aβ-amyloid accumulation: Data from the Australian Imaging, Biomarkers and Lifestyle Study of Ageing

“…A recent cross-sectional study of individuals with MCI or subjective memory impairment ( N = 44) reported a relationship between greater frequency of following a Mediterranean-type diet and less brain Aβ/tau burden as assessed by 2-(1-(6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl)ethylidene)malononitrile ( 18 F-FDDNP); a pan-amyloid PET tracer that binds to both Aβ plaques and tau deposits. Unfortunately, however, the lack of selectivity of the tracer makes it impossible to determine whether the diet was associated with Aβ, tau, or a combination of both 21 . To-date, only one study has specifically examined the relationship between MeDi adherence and cerebral Aβ load.…”