Impact of the Apolipoprotein E ε4 Allele on the Relationship Between Healthy Lifestyle and Cognitive Decline: A Population-Based Study

Association of LIfestyle for BRAin health risk score (LIBRA) and genetic susceptibility with incident dementia and cognitive decline

INTRODUCTION

Evaluating whether genetic susceptibility modifies the impact of lifestyle-related factors on dementia is critical for prevention.

METHODS

We studied 5170 participants from a French cohort of older persons free of dementia at baseline and followed for up to 17 years. The LIfestyle for BRAin health risk score (LIBRA) including 12 modifiable factors was constructed at baseline (higher score indicating greater risk) and was related to both subsequent cognitive decline and dementia incidence, according to genetic susceptibility to dementia (reflected by the apolipoprotein E [APOE] ε4 allele and a genetic risk score [GRS]).

RESULTS

The LIBRA was associated with higher dementia incidence, with no significant effect modification by genetics (hazard ratio for one point score = 1.09 [95% confidence interval, 1.05; 1.13]) in APOE ε4 non-carriers and = 1.15 [1.08; 1.22] in carriers; P = 0.15 for interaction). Similar findings were obtained with the GRS and with cognitive decline.

DISCUSSION

Lifestyle-based prevention may be effective whatever the genetic susceptibility to dementia.

Mid-to-Late Life Healthy Lifestyle Modifies Genetic Risk for Longitudinal Cognitive Aging among Asymptomatic Individuals

IMPORTANCE

Genetic and lifestyle factors contribute to an individual's risk of developing Alzheimer's disease. However, it is unknown whether and how adherence to healthy lifestyles can mitigate the genetic risk of Alzheimer's.

OBJECTIVE

The aim of this study is to investigate whether adherence to healthy lifestyles can modify the impact of genetic predisposition to Alzheimer's disease on later-life cognitive decline.

DESIGN SETTING AND PARTICIPANTS

This prospective cohort study included 891 adults of European ancestry, aged 40 to 65, who were without dementia and had complete healthy-lifestyle and cognition data during the follow-up. Participants joined the Wisconsin Registry for Alzheimer's Prevention (WRAP) beginning in 2001. We conducted replication analyses using a subsample with similar baseline age range from the Health and Retirement Study (HRS).

EXPOSURES

We assessed participants' exposures using a continuous non-APOE polygenic risk score for Alzheimer's, a binary indicator for APOE-ε4 carrier status, and a weighted healthy-lifestyle score, including factors such as no current smoking, regular physical activity, healthy diet, light to moderate alcohol consumption, and frequent cognitive activities.

MAIN OUTCOMES AND MEASURES

We z-standardized cognitive scores for global (Preclinical Alzheimer's Cognitive Composite score 3 - PACC3) and domain-specific assessments (delayed recall and immediate learning).

RESULTS

We followed 891 individuals for up to 10 years (mean [SD] baseline age, 58 [6] years, 31% male, 38% APOE-ε4 carriers). After false discovery rate (FDR) correction, we found statistically significant PRS × lifestyle × age interactions on preclinical cognitive decline but the evidence is stronger among APOE-ε4 carriers. Among APOE-ε4 carriers, PRS-related differences in overall and memory-related domains between people scoring 0-1 and 4-5 regarding healthy lifestyles became evident around age 67 after FDR correction. These findings were robust across several sensitivity analyses and were replicated in the population-based HRS.

CONCLUSION

A favorable lifestyle can mitigate the genetic risk associated with current known non-APOE genetic variants for longitudinal cognitive decline, and these protective effects are particularly pronounced among APOE-ε4 carriers.

Healthy Lifestyle and Cognition in Older Adults With Common Neuropathologies of Dementia

Importance

A healthy lifestyle is associated with better cognitive functioning in older adults, but whether this association is independent of the accumulation of dementia-related pathologies in the brain is uncertain.

Objective

To determine the role of postmortem brain pathology, including β-amyloid load, phosphorylated tau tangles, cerebrovascular pathology, and other brain pathologies, in the association between lifestyle and cognition proximate to death.

Design, Setting, and Participants

This cohort study used data from the Rush Memory and Aging Project, a longitudinal clinical-pathologic study with autopsy data from 1997 to 2022 and up to 24 years of follow-up. Participants included 754 deceased individuals with data on lifestyle factors, cognitive testing proximate to death, and a complete neuropathologic evaluation at the time of these analyses. Data were analyzed from January 2023 to June 2023.

Exposures

A healthy lifestyle score was developed based on self-reported factors, including noncurrent smoking, at least 150 minutes of physical activity per week, limiting alcohol consumption, a Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet score higher than 7.5, and a late-life cognitive activity score higher than 3.2. The lifestyle score ranges from 0 to 5, with higher scores reflecting a healthier lifestyle.

Main Outcomes and Measures

The global cognitive score was derived from a battery of nineteen standardized tests. Brain pathology measures included β-amyloid load, phosphorylated tau tangles, global Alzheimer disease pathology, vascular brain pathologies, Lewy body, hippocampal sclerosis, and TAR DNA-binding protein 43.

Results

Of 586 included decedents, 415 (70.8%) were female, 171 (29.2%) were male, and the mean (SD) age at death was 90.9 (6.0) years. Higher lifestyle score was associated with better global cognitive functioning proximate to death. In the multivariable-adjusted model, a 1-point increase in lifestyle score was associated with 0.216 (SE = 0.036, P < .001) units higher in global cognitive scores. Neither the strength nor the significance of the association changed substantially when common dementia-related brain pathologies were included in the multivariable-adjusted models. The β estimate after controlling for the β-amyloid load was 0.191 (SE = 0.035; P < .001). A higher lifestyle score was associated with lower β-amyloid load in the brain (β = -0.120; SE = 0.041; P = .003), and 11.6% of the lifestyle-cognition association was estimated through β-amyloid load.

Conclusions and Relevance

This study found that in older adults, a healthy lifestyle may provide a cognitive reserve to maintain cognitive abilities independently of common neuropathologies of dementia.

Alzheimer's disease and Alzheimer's disease-related dementias in Hispanics: Identifying influential factors and supporting caregivers

Alzheimer's disease (AD) and Alzheimer's disease-related dementias (ADRD) are the primary public health concerns in the United States and around the globe. AD/ADRD are irreversible mental illnesses that primarily impair memory and thought processes and may lead to cognitive decline among older individuals. The prevalence of AD/ADRD is higher in Native Americans, followed by African Americans and Hispanics. Increasing evidence suggests that Hispanics are the fastest-growing ethnic population in the USA and worldwide. Hispanics develop clinical symptoms of AD/ADRD and other comorbidities nearly seven years earlier than non-Hispanic whites. The consequences of AD/ADRD can be challenging for patients, their families, and caregivers. There is a significant increase in the burden of illness, primarily affecting Hispanic/Latino families. This is partly due to their strong sense of duty towards family, and it is exacerbated by the inadequacy of healthcare and community services that are culturally and linguistically suitable and responsive to their needs. With an increasing age population, low socioeconomic status, low education, high genetic predisposition to age-related conditions, unique cultural habits, and social behaviors, Hispanic Americans face a higher risk of AD/ADRD than other racial/ethnic groups. Our article highlights the status of Hispanic older adults with AD/ADRD. We also discussed the intervention to improve the quality of life in Hispanic caregivers.

"We adjusted for race": now what? A systematic review of utilization and reporting of race in American Journal of Epidemiology and Epidemiology, 2020-2021

Race is a social construct, commonly used in epidemiologic research to adjust for confounding. However, adjustment of race may mask racial disparities, thereby perpetuating structural racism. We conducted a systematic review of articles published in Epidemiology and American Journal of Epidemiology between 2020 and 2021 to (1) understand how race, ethnicity, and similar social constructs were operationalized, used, and reported; and (2) characterize good and poor practices of utilization and reporting of race data on the basis of the extent to which they reveal or mask systemic racism. Original research articles were considered for full review and data extraction if race data were used in the study analysis. We extracted how race was categorized, used-as a descriptor, confounder, or for effect measure modification (EMM)-and reported if the authors discussed racial disparities and systemic bias-related mechanisms responsible for perpetuating the disparities. Of the 561 articles, 299 had race data available and 192 (34.2%) used race data in analyses. Among the 160 US-based studies, 81 different racial categorizations were used. Race was most often used as a confounder (52%), followed by effect measure modifier (33%), and descriptive variable (12%). Fewer than 1 in 4 articles (22.9%) exhibited good practices (EMM along with discussing disparities and mechanisms), 63.5% of the articles exhibited poor practices (confounding only or not discussing mechanisms), and 13.5% were considered neither poor nor good practices. We discuss implications and provide 13 recommendations for operationalization, utilization, and reporting of race in epidemiologic and public health research.

Longitudinal associations between social relationships and cognitive function among Chinese older adults: The mediating role of healthy lifestyles

BACKGROUND

We aimed to explore whether social relationships and cognitive function were reciprocally related and whether healthy lifestyles mediate their association.

METHODS

This study included 3372 Chinese adults from the years 2014-2018 wave of the Chinese Longitudinal Healthy Longevity Survey.

RESULTS

Baseline social relationships were negatively associated with a change in cognitive function (β = -0.030, p = 0.043). Participants with a 1 standard deviation (SD) increase in social relationships had an approximately 6% reduced risk of developing cognitive impairment. However, baseline cognitive function did not independently predict social relationships. The association between △social relationships and △cognitive function was partially mediated by △a healthy lifestyle (B = 0.025, 95% CI = 0.013-0.041).

CONCLUSIONS

The association between social relationships and cognitive function may be unidirectional. Policies that promote cognitive function based on social relationships would benefit by taking into account lifestyle factors.

Vitamin D intake and cognitive decline in Blacks and Whites: The role of diet and supplements

INTRODUCTION

To determine the role of vitamin D intake on cognitive decline among Blacks and Whites.

METHODS

Using data from the population-based Chicago Health and Aging Project, we studied 2061 Blacks and 1329 Whites with dietary vitamin D data and cognitive testing over 12 years of follow-up. Multivariable linear mixed-effects models were used to determine the association of vitamin D intake with cognitive decline.

RESULTS

Vitamin D intake, particularly dietary vitamin D, was associated with a slower rate of decline in cognitive function among Blacks. In Blacks, comparing individuals in the lowest tertile of dietary intake, those in the highest tertile had a slower cognitive decline of 0.017 units/year (95% confidence interval 0.006, 0.027), independently of supplementation use. In Whites, vitamin D intake was not associated with cognitive decline.

DISCUSSION

Dietary vitamin D may help to slow the decline in cognitive abilities among Blacks as they age.

Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study

OBJECTIVE

To identify an optimal lifestyle profile to protect against memory loss in older individuals.

DESIGN

Population based, prospective cohort study.

SETTING

Participants from areas representative of the north, south, and west of China.

PARTICIPANTS

Individuals aged 60 years or older who had normal cognition and underwent apolipoprotein E (APOE) genotyping at baseline in 2009.

MAIN OUTCOME MEASURES

Participants were followed up until death, discontinuation, or 26 December 2019. Six healthy lifestyle factors were assessed: a healthy diet (adherence to the recommended intake of at least 7 of 12 eligible food items), regular physical exercise (≥150 min of moderate intensity or ≥75 min of vigorous intensity, per week), active social contact (≥twice per week), active cognitive activity (≥twice per week), never or previously smoked, and never drinking alcohol. Participants were categorised into the favourable group if they had four to six healthy lifestyle factors, into the average group for two to three factors, and into the unfavourable group for zero to one factor. Memory function was assessed using the World Health Organization/University of California-Los Angeles Auditory Verbal Learning Test, and global cognition was assessed via the Mini-Mental State Examination. Linear mixed models were used to explore the impact of lifestyle factors on memory in the study sample.

RESULTS

29 072 participants were included (mean age of 72.23 years; 48.54% (n=14 113) were women; and 20.43% (n=5939) were APOE ε4 carriers). Over the 10 year follow-up period (2009-19), participants in the favourable group had slower memory decline than those in the unfavourable group (by 0.028 points/year, 95% confidence interval 0.023 to 0.032, P<0.001). APOE ε4 carriers with favourable (0.027, 95% confidence interval 0.023 to 0.031) and average (0.014, 0.010 to 0.019) lifestyles exhibited a slower memory decline than those with unfavourable lifestyles. Among people who were not carriers of APOE ε4, similar results were observed among participants in the favourable (0.029 points/year, 95% confidence interval 0.019 to 0.039) and average (0.019, 0.011 to 0.027) groups compared with those in the unfavourable group. APOE ε4 status and lifestyle profiles did not show a significant interaction effect on memory decline (P=0.52).

CONCLUSION

A healthy lifestyle is associated with slower memory decline, even in the presence of the APOE ε4 allele. This study might offer important information to protect older adults against memory decline.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03653156.

Lifestyle and Cognitive Decline in Community-Dwelling Stroke Survivors

Background: Patients with stroke are at a higher risk of cognitive impairment and Alzheimer’s disease dementia. Objective: To quantify the role of lifestyle pre-stroke, post-stroke, and changes in lifestyle before and after stroke with cognitive decline in community-dwelling stroke survivors. Methods: Utilizing data from the Chicago Health and Aging Project, a population-based cohort study, we studied 1,078 individuals with stroke (662 incident and 416 prevalent) who underwent cognitive testing during the study period. A healthy lifestyle score was defined by scoring four behaviors: non-smoking, exercising, being cognitively active, and having a high-quality diet. The global cognitive score was derived from a comprehensive battery of 4 standardized tests. Results: The mean age at incident stroke was 78.2 years, and 60.1% were women. A healthy lifestyle pre-incident stroke was associated with a slower rate of cognitive decline after stroke. Participants with 3–4 healthy lifestyle factors pre-incident stroke had a slower cognitive decline after stroke by 0.046 units/year (95% CI 0.010, 0.083), or 47.7% slower, than participants with 0–1 healthy lifestyle factor. Lifestyle score post-prevalent stroke was not associated with cognitive decline. Changes in lifestyle behaviors from pre- to post-incident stroke were related to cognitive decline after stroke. Individuals who deteriorated their lifestyle quality after stroke had a faster cognitive decline by 0.051 units/year (β –0.051, 95% CI –0.090, –0.012) than participants with no change in lifestyle score. Conclusion: A healthy lifestyle pre-stroke was associated with a slower rate of cognitive decline in stroke survivors, highlighting the importance of primary prevention. After the stroke, changes in lifestyle behaviors may influence the cognitive abilities of older adults as they age.

Healthy lifestyle and life expectancy with and without Alzheimer's dementia: population based cohort study

OBJECTIVE

To determine the impact of lifestyle factors on life expectancy lived with and without Alzheimer's dementia.

DESIGN

Prospective cohort study.

SETTING

The Chicago Health and Aging Project, a population based cohort study in the United States.

PARTICIPANTS

2449 men and women aged 65 years and older.

MAIN EXPOSURE

A healthy lifestyle score was developed based on five modifiable lifestyle factors: a diet for brain health (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay-MIND diet score in upper 40% of cohort distribution), late life cognitive activities (composite score in upper 40%), moderate or vigorous physical activity (≥150 min/week), no smoking, and light to moderate alcohol consumption (women 1-15 g/day; men 1-30 g/day).

MAIN OUTCOME

Life expectancy with and without Alzheimer's dementia in women and men.

RESULTS

Women aged 65 with four or five healthy factors had a life expectancy of 24.2 years (95% confidence interval 22.8 to 25.5) and lived 3.1 years longer than women aged 65 with zero or one healthy factor (life expectancy 21.1 years, 19.5 to 22.4). Of the total life expectancy at age 65, women with four or five healthy factors spent 10.8% (2.6 years, 2.0 to 3.3) of their remaining years with Alzheimer's dementia, whereas women with zero or one healthy factor spent 19.3% (4.1 years, 3.2 to 5.1) with the disease. Life expectancy for women aged 65 without Alzheimer's dementia and four or five healthy factors was 21.5 years (20.0 to 22.7), and for those with zero or one healthy factor it was 17.0 years (15.5 to 18.3). Men aged 65 with four or five healthy factors had a total life expectancy of 23.1 years (21.4 to 25.6), which is 5.7 years longer than men aged 65 with zero or one healthy factor (life expectancy 17.4 years, 15.8 to 20.1). Of the total life expectancy at age 65, men with four or five healthy factors spent 6.1% (1.4 years, 0.3 to 2.0) of their remaining years with Alzheimer's dementia, and those with zero or one healthy factor spent 12.0% (2.1 years, 0.2 to 3.0) with the disease. Life expectancy for men aged 65 without Alzheimer's dementia and four or five healthy factors was 21.7 years (19.7 to 24.9), and for those with zero or one healthy factor life expectancy was 15.3 years (13.4 to 19.1).

CONCLUSION

A healthy lifestyle was associated with a longer life expectancy among men and women, and they lived a larger proportion of their remaining years without Alzheimer's dementia. The life expectancy estimates might help health professionals, policy makers, and stakeholders to plan future healthcare services, costs, and needs.

ApoE Cascade Hypothesis in the pathogenesis of Alzheimer's disease and related dementias

The ε4 allele of the apolipoprotein E gene (APOE4) is a strong genetic risk factor for Alzheimer's disease (AD) and several other neurodegenerative conditions, including Lewy body dementia (LBD). The three APOE alleles encode protein isoforms that differ from one another only at amino acid positions 112 and 158: apoE2 (C112, C158), apoE3 (C112, R158), and apoE4 (R112, R158). Despite progress, it remains unclear how these small amino acid differences in apoE sequence among the three isoforms lead to profound effects on aging and disease-related pathways. Here, we propose a novel "ApoE Cascade Hypothesis" in AD and age-related cognitive decline, which states that the biochemical and biophysical properties of apoE impact a cascade of events at the cellular and systems levels, ultimately impacting aging-related pathogenic conditions including AD. As such, apoE-targeted therapeutic interventions are predicted to be more effective by addressing the biochemical phase of the cascade.

Genetic risk, adherence to a healthy lifestyle, and cognitive decline in African Americans and European Americans

INTRODUCTION

We investigated the role of genetic risk and adherence to lifestyle factors on cognitive decline in African Americans and European Americans.

METHODS

Using data from the Chicago Health and Aging Project (1993-2012; n = 3874), we defined the genetic risk based on presence of apolipoprotein E (APOE) ε 4 allele and determined a healthy lifestyle using a scoring of five factors: non-smoking, exercising, being cognitively active, having a high-quality diet, and limiting alcohol use. We used linear mixed-effects models to estimate cognitive decline by genetic risk and lifestyle score.

RESULTS

APOE  ε 4 allele was associated with faster cognitive decline in both races. However, within APOE  ε 4 carriers, adherence to a healthy lifestyle (eg., 4 to 5 healthy factors) was associated with a slower cognitive decline by 0.023 (95% confidence interval [CI] 0.004, 0.042) units/year in African Americans and 0.044 (95% CI 0.008, 0.080) units/year in European Americans.

DISCUSSION

A healthy lifestyle was associated with a slower cognitive decline in African and European Americans.