Mortality and apolipoprotein E in Hispanic, African-American, and Caucasian elders

Association of APOE Genotypes and Chronic Traumatic Encephalopathy

Importance

Repetitive head impact (RHI) exposure is the chief risk factor for chronic traumatic encephalopathy (CTE). However, the occurrence and severity of CTE varies widely among those with similar RHI exposure. Limited evidence suggests that the APOEε4 allele may confer risk for CTE, but previous studies were small with limited scope.

Objective

To test the association between APOE genotype and CTE neuropathology and related endophenotypes.

Design, Setting, and Participants

This cross-sectional genetic association study analyzed brain donors from February 2008 to August 2019 from the Veterans Affairs-Boston University-Concussion Legacy Foundation Brain Bank. All donors had exposure to RHI from contact sports or military service. All eligible donors were included. Analysis took place between June 2020 and April 2022.

Exposures

One or more APOEε4 or APOEε2 alleles.

Main Outcomes and Measures

CTE neuropathological status, CTE stage (0-IV), semiquantitative phosphorylated tau (p-tau) burden in 11 brain regions (0-3), quantitative p-tau burden in the dorsolateral frontal lobe (log-transformed AT8+ pixel count per mm2), and dementia.

Results

Of 364 consecutive brain donors (100% male; 53 [14.6%] self-identified as Black and 311 [85.4%] as White; median [IQR] age, 65 [47-77] years) 20 years or older, there were 294 individuals with CTE and 70 controls. Among donors older than 65 years, APOEε4 status was significantly associated with CTE stage (odds ratio [OR], 2.34 [95% CI, 1.30-4.20]; false discovery rate [FDR]-corrected P = .01) and quantitative p-tau burden in the dorsolateral frontal lobe (β, 1.39 [95% CI, 0.83-1.94]; FDR-corrected P = 2.37 × 10-5). There was a nonsignificant association between APOEε4 status and dementia (OR, 2.64 [95% CI, 1.06-6.61]; FDR-corrected P = .08). Across 11 brain regions, significant associations were observed for semiquantitative p-tau burden in the frontal and parietal cortices, amygdala, and entorhinal cortex (OR range, 2.45-3.26). Among football players, the APOEε4 association size for CTE stage was similar to playing more than 7 years of football. Associations were significantly larger in the older half of the sample. There was no significant association for CTE status. Association sizes were similar when donors with an Alzheimer disease neuropathological diagnosis were excluded and were reduced but remained significant after adjusting for neuritic and diffuse amyloid plaques. No associations were observed for APOEε2 status. Models were adjusted for age at death and race.

Conclusions and Relevance

APOEε4 may confer increased risk for CTE-related neuropathological and clinical outcomes among older individuals with RHI exposure. Further work is required to validate these findings in an independent sample.

Identification of cardiovascular health gene variants related to longevity in a Chinese population

Cardiovascular disease (CVD) is one of the most important causes of human death, but no attention has been paid to cardiovascular health genes related to healthy longevity. Therefore, we developed a cohort study to explore such genes in healthy, long-lived Chinese subjects. A total of 13275 healthy elderly people were enrolled, including 5107 healthy long-lived individuals and 8168 age-matched control individuals with low CVD risk. Using a combination of whole-exome sequencing (WES) and genome-wide association studies (GWAS), we identified 2 genetic variants (TFPI rs7586970 T, p=0.013, OR=1.100. ADAMTS7 rs3825807 A, p=0.017, OR=1.198) associated with healthy lipid metabolism and longevity. Furthermore, we showed that an interaction among TFPI rs7586970, ADAMTS7 rs3825807 and APOE ɛ3 maintained normal blood lipid levels in centenarians by stratified analysis of CVD risk factors. Finally, through biological function analysis, we revealed clues regarding the mechanism of factor related to cardiovascular health (FCH) such as lipids and longevity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the two variants above may be associated with longevity via FCH lipid metabolism pathways. From a meta-analysis of venous thrombosis patients, we unexpectedly found that rs7586970 T is associated with both longevity and protection against vascular disease.

The Influence of Education and Apolipoprotein ε4 on Mortality in Community-Dwelling Elderly Men and Women

We investigated the risk of death in relation to the apolipoprotein ε4 allele and evaluated how it interacts with education in 504 elderly adults (mean age 73 years, 65.3% women) who were enrolled in 1993 into the New Mexico Aging Process Study. During 9 years of follow-up, apolipoprotein ε2 appeared to be associated with a lower risk for all-cause mortality (hazard ratio (HR) = 0.73, 95% confidence interval (CI): 0.30-1.71) compared to apolipoprotein ε3 carriers in models adjusted for age, sociodemographic variables, medical conditions, adiposity, and lifestyle factors. The apolipoprotein ε4 allele conferred almost a threefold elevated risk of mortality (HR = 2.76, CI: 1.42-5.37). An interaction between education and apolipoprotein e4 (p=0.027) was observed with the HR of mortality among e4 carriers compared to noncarriers being 1.59 (0.64-3.96) for those with ≥college education; 6.66 (1.90-23.4) for those with some college or trade; and 14.1 (3.03-65.6) for participants with ≤high school education. No significant interaction was identified between apolipoprotein E genotype and cognitive function for mortality risk. These findings suggest that genetic (apolipoprotein ε4) and environmental (education) factors act interactively to influences survival in the elderly with higher education attenuating the adverse effect of apolipoprotein ε4 on mortality.

No association between Apoε4 alleles, HIV infection, age, neuropsychological outcome, or death

The ε4 allele of the apolipoprotein E (ApoE) gene may have important interactions with physical health and cognitive function among individuals with HIV disease. The purpose of this study is to examine the relationships between ε4, HIV disease, age, neuropsychological impairment, and death in a large, well-characterized study sample. A total of 2846 men participating in the Multicenter AIDS Cohort Study had ApoE genotyping and neuropsychological test data available for analysis. We found a significant association between HIV infection and time to death (from any cause), as well as older age, race, and education. But, ApoE status was not significantly associated with time to death. Similarly, we found a significant association between HIV infection and time to incident cognitive impairment, as well as age, education, and HIV serostatus; Apoε4 status was not related to incident cognitive impairment. There were no significant interactions between ApoE, HIV infection, and age on cognitive impairment. These data replicate and strengthen prior findings of the lack of association between ApoE ε4 and cognitive outcomes in HIV disease. We conclude that within the specific constraints of an exclusively male study in which the majority of participants were less than 65 years of age (range 22-87 years), it appears reasonable to conclude that the ε4 allele is not significantly interacting with HIV serostatus.

The three genetics (nuclear DNA, mitochondrial DNA, and gut microbiome) of longevity in humans considered as metaorganisms

Usually the genetics of human longevity is restricted to the nuclear genome (nDNA). However it is well known that the nDNA interacts with a physically and functionally separated genome, the mitochondrial DNA (mtDNA) that, even if limited in length and number of genes encoded, plays a major role in the ageing process. The complex interplay between nDNA/mtDNA and the environment is most likely involved in phenomena such as ageing and longevity. To this scenario we have to add another level of complexity represented by the microbiota, that is, the whole set of bacteria present in the different part of our body with their whole set of genes. In particular, several studies investigated the role of gut microbiota (GM) modifications in ageing and longevity and an age-related GM signature was found. In this view, human being must be considered as “metaorganism” and a more holistic approach is necessary to grasp the complex dynamics of the interaction between the environment and nDNA-mtDNA-GM of the host during ageing. In this review, the relationship between the three genetics and human longevity is addressed to point out that a comprehensive view will allow the researchers to properly address the complex interactions that occur during human lifespan.

New insights into the distribution of APOE polymorphism in the Iberian Peninsula. The case of Andalusia (Spain)

BACKGROUND

The APOE gene has received much attention due to the remarkable spatial variation patterns of some of its genotypes and alleles in human populations and to its relevance in biomedicine.

AIM

This work was addressed to investigate the extent of APOE polymorphism between autochthonous Andalusians originating from Huelva and Granada provinces. No data on this marker in these southern Spanish coastal populations are available up to date.

SUBJECTS AND METHODS

This study used genomic DNA from healthy, unrelated Andalusians of both sexes (n = 322). All samples were genotyped for two SNPs, rs429358 and rs7412, which determine the three APOE alleles: ε2, ε3 and ε4. For analyses, a TaqMan-based technique was applied using a RT-PCR. Comparisons with other Mediterranean populations were performed based on multivariate analysis.

RESULTS

A relatively high frequency of ε4 in Granada (eastern Andalusia), as well as a low ε2 frequency in Huelva (western Andalusia) were observed. The finding that ε4 allele in Southern Spain and Portugal is higher than expected given its geographical location poses an interesting question for this study, given the well-established APOE-ε4 gradient in Europe.

CONCLUSION

This population study may represent useful information for further prospective anthropological and molecular genetic studies focused on unravelling the relationship between population genetic composition and specific human diseases.

Apolipoprotein E ε4 allele interacts with sex and cognitive status to influence all-cause and cause-specific mortality in U.S. older adults

OBJECTIVES

To confirm associations of apolipoprotein E (ApoE) ε4 carrier status, sex, and time-dependent cognitive status with mortality risk and to investigate these joint effects of these associations in a cohort of community-dwelling U.S. adults.

DESIGN

Prospective cohort study.

SETTING

The Baltimore Longitudinal Study of Aging (BLSA).

PARTICIPANTS

Of 3,047 BLSA participants aged 17 to 98 at first visit (60.1% male), 1,704 with complete ApoE genotype data were included, of whom 1,461 aged 50 and older with one or more visits were eligible.

MEASUREMENTS

Time to death from all, cardiovascular, and noncardiovascular causes.

RESULTS

Probability of survival was lower for ApoE ε4 carriers, particularly those who were older. A Cox proportional hazards model for all-cause mortality yielded a hazard ratio (HR) for ApoE ε4 carrier versus noncarriers of 1.31 (95% confidence interval (CI) = 1.02-1.68). This association was also found for cardiovascular mortality. Time-dependent all-cause dementia (HR = 1.73, 95% CI = 1.33-2.26) and mild cognitive impairment (HR = 1.95, 95% CI = 1.42-2.67) increased all-cause mortality risk, associations that were also detected for noncardiovascular mortality. When individuals were free of cognitive impairment, a dose-response relationship with ε4 alleles was found for all-cause mortality (HR = 1.40, 95% CI = 0.94-2.07 for 1 ε4; HR = 2.61, 95% CI = 1.12-6.07 for 2 ε4). After onset of Alzheimer's disease (AD), carrying only one ε4 allele resulted in an approximately 77% greater all-cause mortality risk than in noncarriers. ApoE ε4 carrier status increased all-cause mortality risk in men and interacted with time-dependent AD to increase the risk of this outcome (relative excess risk due to interaction = 2.15, 95% CI = 1.22-3.07).

CONCLUSION

ApoE ε4 carrier status was found to increase all-cause and cardiovascular mortality risks and interacted with sex and time-dependent AD status to affect all-cause mortality.

Association of shorter leukocyte telomere repeat length with dementia and mortality

BACKGROUND

Shortening of chromosomal telomeres is a consequence of cell division and is a biological factor related to cellular aging and potentially to more rapid organismal biological aging.

OBJECTIVE

To determine whether shorter telomere length (TL), as measured in human blood samples, is associated with the development of Alzheimer disease and mortality.

DESIGN

We studied available stored leukocyte DNA from a community-based study of aging using realtime polymerase chain reaction analysis to determine mean TL in our modification of a method measuring the ratio of telomere sequence to single-copy gene sequence.

SETTING

A multiethnic community-based study of aging and dementia.

PARTICIPANTS

One thousand nine hundred eighty-three subjects 65 years or older. Mean (SD) age at blood draw was 78.3 (6.9) years; at death, 86.0 (7.4) years. Median follow-up for mortality was 9.3 years; 190 (9.6%) developed incident dementia.

RESULTS

The TL was inversely related to age and shorter in men than women. Persons dying during follow-up had a shorter TL compared with survivors (mean [SD], 6218 [819] vs 6491 [881] base pairs [bp] [P.001]), even after adjustment for age, sex, education, and apolipoprotein E genotype. Individuals who developed dementia had significantly shorter TL (mean [SD], 6131 [798] bp for prevalent cases and 6315 [817] bp for incident cases) compared with those remaining dementia-free (6431 [864] bp). Cox-regression analyses showed that shorter TL was a risk for earlier onset of dementia (P=.05), but stratified analyses for sex showed that this association of age at onset of dementia with shorter TL was significant in women only.

CONCLUSION

Our findings suggest that shortened leukocyte TL is associated with risks for dementia and mortality and may therefore be a marker of biological aging.

Apolipoprotein E and measured physical and pulmonary function in older Taiwanese adults

The apolipoprotein E (ApoE) gene, which has three common alleles (ϵ2, ϵ3, and ϵ4), has been linked to a number of health outcomes and longevity. The ϵ2 allele has been reported to have neuroprotective effects, whereas the ϵ4 allele has been shown to be a risk factor for cardiovascular disease and Alzheimer's disease in various populations. The relationships between ApoE and mortality and ApoE and physical function, however, are not clear-cut. We used the Social Environment and Biomarkers of Aging Study (SEBAS) to examine the relationship between ApoE polymorphisms and physical and pulmonary function in approximately 1,000 Taiwanese adults aged 53 years and older in 2006. In the 2006 SEBAS wave, measures of physical function included self-reported difficulties with respect to activities of daily living (ADLs) and other physical function indicators, as well as performance-based measures of grip strength (kg), walking speed (m/s) over a distance of 3 m, and chair stand speed (stand/s). Peak expiratory flow (PEF; L/min) rate was also examined as an indicator of pulmonary function. We used logistic regression models to determine the association between ApoE and inability to complete each of the tests of physical and pulmonary function. These models revealed no significant association between ApoE carrier status and any of the indicators of function. Among participants able to complete a given task, we next used linear regression models to examine self-reported limitations with ADLs and performance on the given test by ApoE carrier status. Similarly, there were no significant relationships between ApoE carrier status and the measures of function. Our estimates provide further confirmation that the ApoE gene may not be a risk factor for functional decline among older Taiwanese adults.

Apolipoprotein E and familial longevity

Exceptional longevity is associated with substantial heritability. The ε4 allele in apolipoprotein E and the linked G allele in rs2075650 of TOMM40 have been associated with increased mortality and the ε2 allele with decreased mortality, although inconsistently. Offspring from long-lived families and spouse controls were recruited at 3 sites in the United States and Denmark. We used generalized estimating equations to compare the likelihood of carrying risk alleles in offspring (n = 2307) and spouse controls (n = 764), adjusting for age, sex, level of education, and family membership. The likelihood of carrying an APOE ε4 allele or a G allele in rs2075650 was lower (odds ratio [OR], 0.75; p = 0.005 and OR, 0.70; p = 0.002) and the likelihood of carrying an APOE ε2 allele was higher (OR, 1.5; p = 0.007) among family members in the offspring generation than among their spouse controls. Our findings support the hypothesis that both reduction in the frequency of the ε4 allele and increase in the frequency of the ε2 allele contribute to longevity.

Apolipoprotein E is associated with blood lipids and inflammation in Taiwanese older adults

Polymorphisms of the apolipoprotein E gene (ApoE) have been associated with health and longevity. Numerous studies have linked ApoE to health outcomes including cardiovascular disease and mortality, but far fewer studies have examined the relationship of ApoE to other biological markers of health. This study investigates the relationship between ApoE and mortality, as well as ApoE and a set of biomarkers related to cardiovascular and immune function, in a population-based sample of Taiwanese adults ages 54+. ApoE £2 carriers were less likely to have at-risk levels of high-density lipoprotein (HDL-C) and total cholesterol (total-C) than non-carriers (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.25-0.83 and OR 0.45, 95% CI 0.29-0.71, respectively). ApoE £4 carriers were less likely to have elevated levels of C-reactive protein (CRP) than non-carriers (OR 0.62, 95% CI 0.39-0.96). ApoE genotype was not, however, associated with mortality after 8 years of follow-up. Our findings confirm the association between ApoE £2and cholesterol levels, suggesting a potential protective effect of ApoE £2 on blood lipids. They also contribute to reports on the relationship between ApoE £4 carrier status and lower CRP levels.

Physical activity and Alzheimer disease course

OBJECTIVES

To examine the association between physical activity (PA) and Alzheimer disease (AD) course.

BACKGROUND

PA has been related to lower risk for AD. Whether PA is associated with subsequent AD course has not been investigated.

METHODS

In a population-based study of individuals aged 65 years and older in New York who were prospectively followed up with standard neurologic and neuropsychological evaluations (every ~1.5 years), 357 participants i) were nondemented at baseline and ii) were diagnosed with AD during follow-up (incident AD). PA (sum of participation in a variety of physical activities, weighted by the type of activity [light, moderate, and severe]) obtained 2.4 (standard deviation [SD], 1.9) years before incidence was the main predictor of mortality in Cox models and of cognitive decline in generalized estimating equation models that were adjusted for age, gender, ethnicity, education, comorbidities, and duration between PA evaluation and dementia onset.

RESULTS

One hundred fifty incident AD cases (54%) died during the course of 5.2 (SD, 4.4) years of follow-up. When compared with incident AD cases who were physically inactive, those with some PA had lower mortality risk, whereas incident AD participants with much PA had an even lower risk. Additional adjustments for apolipoprotein genotype, smoking, comorbidity index, and cognitive performance did not change the associations. PA did not affect rates of cognitive or functional decline.

CONCLUSION

Exercise may affect not only risk for AD but also subsequent disease duration: more PA is associated with prolonged survival in AD.

Apolipoprotein E-related all-cause mortality in hospitalized elderly patients

The most common apolipoprotein E (APOE) allelic variation is implicated in many age-related diseases and human longevity with controversial findings. We investigated the effect of APOE gene polymorphism on all-cause mortality in elderly patients taking into consideration the functional disability, cognitive impairment, malnutrition, and the occurrence of common age-related diseases. APOE genotypes were determined in 2,124 geriatric hospitalized patients (46.5% men and 53.5% women; mean age, 78.2 +/- 7.1 years; range, 65-100 years). At hospital admission, all patients underwent a comprehensive geriatric assessment to evaluate functional disability, cognitive status, nutritional status, and comorbidity. The main and secondary diagnoses at hospital discharge were also recorded. Mortality status was evaluated in all patients after a maximum follow-up of 5 years (range, from 1.26 to 5.23 years; median, 2.86 years). During the study period, 671 patients died (32.0%). At hospital admission, these patients showed a significant higher prevalence of cardiovascular diseases (56.3% vs 53.4%; p = 0.007), neoplasias (32.3% vs 13.7%; p < 0.001), and lower prevalence of neurodegenerative diseases (17.7% vs 20.7%; p < 0.001) than survived patients. Moreover, they also showed an higher prevalence of disability (52.0% vs 25.6%; p < 0.001), cognitive impairment (31.0% vs 18.8%; p < 0.001), and malnutrition (74.0% vs 46.1%; p < 0.001) than survived patients. In the overall study population, the APOE epsilon2 allele was significantly associated to neurodegenerative diseases (odds ratio = 0.59; 95% confidence interval (CI), 0.37-0.94). No significant association between the APOE polymorphism and disability, malnutrition, co-morbidity status, and with all-cause mortality was observed. In patients with cardiovascular diseases, however, a decreased risk of all-cause mortality was found in the epsilon2 allele carriers (hazard ratio = 0.56; 95% CI, 0.36-0.88). In this population, APOE allele variants might play a role on cardiovascular disease-related mortality.

The NIH Cognitive and Emotional Health Project. Report of the Critical Evaluation Study Committee

BACKGROUND

The Cognitive and Emotional Health Project (CEHP) seeks to identify the demographic, social, and biological determinants of cognitive and emotional health in the older adult. As part of the CEHP, a critical evaluation study committee was formed to assess the state of epidemiological research on demographic, social, and biological determinants of cognitive and emotional health.

METHODS

Criteria for inclusion in the survey were large cohort studies, longitudinal in design, participants predominantly 65 years or older, with measurements of both cognition and emotion, and information on a wide variety of demographic, psychosocial, and biological factors. North American and European studies, which met these criteria, were selected for the review. Outcome measures included cognition, cognitive decline, and cognitive function. For emotion, symptoms included depression and anxiety, positive and negative affect, subjective well being, mastery, and resilience.

RESULTS

Ninety-six papers were identified that addressed cognitive and emotional outcomes. A large variety of risk factors were consistently identified with cognitive outcomes, particularly those previously associated with increased risk of cardiovascular disease. There was considerable overlap between risk factors for cognitive and emotional outcomes.

CONCLUSION

This review identifies a large number of lifestyle and health behaviors that alter the risk for maintenance of cognitive and emotional health. Large longitudinal cohort studies are a unique source to explore factors associated with cognitive and emotional health. Secondary analyses of these studies should be encouraged as should the development of standardized questionnaires to measure cognitive and emotional health. Future research in this field should study cognitive and emotional health simultaneously.

Apoetm1Unc mice have impaired alveologenesis, low lung function, and rapid loss of lung function

Diminished lung function, indicated by a low forced expiratory volume in one second (FEV1), and short physical stature, predict early mortality from all causes, including cardiovascular, among smokers and never smokers. The basis for these associations is unclear, and, it is not known if there is a pulmonary morphological component to the relationship between low FEV1 and early death in a general population. Some apolipoprotein E genotypes also predict atherosclerosis and early mortality. These considerations led us to examine the Apoe tm1Unc (Apoe) mouse, in which the apolipoprotein E gene is deleted, and that develops dyslipidemia, atherosclerosis at an early age, and has a shorter life span than the founder wild-type (wt) strain. We asked if Apoe mice have a morphological or functional pulmonary phenotype. We measured the size, number, and surface area of pulmonary gas-exchange units (alveoli) and mechanical properties of the lung. Compared with wt mice, Apoe mice had: 1) diminished developmental alveologenesis, 2) increased airway resistance in early adulthood, 3) high lung volume and high dynamic and static compliance in later adulthood, 4) more rapid loss of lung recoil with age, and 5) were less long than wt mice. These findings in mice indicate the association of a low FEV1 with early death in humans may have developmental, and accelerated ageing, related pulmonary components, and that dietary, genetic, or dietary and genetic influences, on lipid metabolism may be an upstream cause of inflammation and oxidative stress, currently considered to be major risk factors for COPD.

Lipoproteins, vascular-related genetic factors, and human longevity

The relationships among lipoprotein metabolism, genetic vascular factors, vascular disease, and Alzheimer's disease suggest that the examination of centenarian populations in relation to certain genes or lipoprotein metabolism provide insights into human longevity. The findings on the higher frequency of the apolipoprotein E epsilon4 allele in middle-aged subjects than in centenarians were substantially confirmed. On the contrary, recent findings did not confirm previous data on increased prevalence of the high-risk angiotensin I converting enzyme D allele in French centenarians. The variability in the strength of association between angiotensin I converting enzyme polymorphism and longevity could be related to regional differences in angiotensin I converting enzyme D allele frequency in Europe recently showed, as also recently reported for apolipoprotein Eepsilon2 and epsilon4 allele in centenarians. Indeed some studies of lipoprotein profiles in centenarians have also had contradictory outcomes, with evidence of lower serum levels of high-density lipoprotein cholesterol, with higher high-density lipoprotein 2 cholesterol subfraction, larger high-density lipoprotein and low-density lipoprotein particle sizes, and higher lipoprotein(a) concentration in centenarians, which is apparently disadvantageous for human longevity. Elevated lipoprotein(a) serum levels, increasing the risk for cerebrovascular disease, may play a role in determining clinical Alzheimer's disease, but lipoprotein(a) elevation in centenarians, in the absence of other coronary artery disease risk factors, appears as a positive survival factor. In different populations, there are significant trends in the reduction of serum apolipoprotein E levels from apolipoprotein E epsilon2- to epsilon4-carriers and significant differences in serum apolipoprotein E levels with respect to age in epsilon4-carriers but only after adjustment for high-density lipoprotein cholesterol. While further studies are needed to confirm the possible role of apolipoprotein E concentration as putative longevity factor this paper provides an overview of many of the investigated vascular factors with respect to longevity.

Apolipoprotein E gene is related to mortality only in normal weight individuals: the Rotterdam Study

Objective To investigate the relationship between the apolipoprotein E (APOE) gene and the risk of mortality in normal weight, overweight and obese individuals. Methods and Results In a population-based study of 7,983 individuals aged 55 years and older, we compared the risks of all-cause and coronary heart disease (CHD) mortality by APOE genotype, both overall and in subgroups defined by body mass index (BMI). We found significant evidence for interaction between APOE and BMI in relation to total cholesterol (p = 0.04) and HDL cholesterol (p < 0.001). Overall, APOE*2 carriers showed a decreased risk of all-cause mortality. Analyses within BMI strata showed a beneficial effect of APOE*2 only in normal weight persons (adjusted hazard ratio (HR) 0.7[95% CI 0.5–0.9]). APOE*2 was not associated with a lower risk of all-cause mortality in overweight or obese persons. The effect of APOE*2 in normal weight individuals tended to be due to the risk of CHD mortality (adjusted HR 0.5 [95% CI 0.2–1.2]). Conclusion The APOE*2 allele confers a lower risk of all-cause mortality only to normal weight individuals.

Mediterranean diet and Alzheimer disease mortality

BACKGROUND

We previously reported that the Mediterranean diet (MeDi) is related to lower risk for Alzheimer disease (AD). Whether MeDi is associated with subsequent AD course and outcomes has not been investigated.

OBJECTIVES

To examine the association between MeDi and mortality in patients with AD.

METHODS

A total of 192 community-based individuals in New York who were diagnosed with AD were prospectively followed every 1.5 years. Adherence to the MeDi (0- to 9-point scale with higher scores indicating higher adherence) was the main predictor of mortality in Cox models that were adjusted for period of recruitment, age, gender, ethnicity, education, APOE genotype, caloric intake, smoking, and body mass index.

RESULTS

Eighty-five patients with AD (44%) died during the course of 4.4 (+/-3.6, 0.2 to 13.6) years of follow-up. In unadjusted models, higher adherence to MeDi was associated with lower mortality risk (for each additional MeDi point hazard ratio 0.79; 95% CI 0.69 to 0.91; p = 0.001). This result remained significant after controlling for all covariates (0.76; 0.65 to 0.89; p = 0.001). In adjusted models, as compared with AD patients at the lowest MeDi adherence tertile, those at the middle tertile had lower mortality risk (0.65; 0.38 to 1.09; 1.33 years' longer survival), whereas subjects at the highest tertile had an even lower risk (0.27; 0.10 to 0.69; 3.91 years' longer survival; p for trend = 0.003).

CONCLUSION

Adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect.

Differences in the Association Between Apolipoprotein E Genotype and Mortality Across Populations

BACKGROUND

The gene for apolipoprotein-E (APOE) has three common alleles (epsilon2, epsilon3, and epsilon4) that have been shown to be associated with differences in the risk of death in persons older than 60 years in European populations. However, previous research suggests that they may not be associated with mortality in African Americans, and the evidence in Asians is mixed. It is now possible to examine the effects of these genotypes on mortality in African American, Chinese, Japanese, and Korean populations.

METHODS

The analysis is based on two types of published data: genotype by age and mortality by genotype. Demographic synthesis uses a multistate model to combine data from these case-control and cohort studies to provide maximum likelihood estimates of the relative risks of death.

RESULTS

In general, the APOE epsilon2 allele is associated with 5%-10% lower mortality than the epsilon3/3 genotype. The epsilon4/4 allele is generally associated with a moderately high relative risk of death. The epsilon3/4 genotype is associated with 22% excess risk in Europeans and U.S. whites and with about 35% in Chinese. However, there is no evidence of excess risk with epsilon3/4 among African Americans and little excess risk among Japanese and Koreans. The relationship between genotype and mortality is consistent within these ethnic groups. For example, the estimates of R(3/4) for Japanese in Japan and Hawaii are both low, and the estimates for Chinese in Taiwan and Shanghai are relatively high.

CONCLUSIONS

. The relationship between APOE genotype and mortality differs across population groups but shows little evidence of variation within groups.

Analysis of common polymorphisms in angiotensin-converting enzyme and apolipoprotein e genes and human longevity in Colombia

BACKGROUND

Genetic analysis of human longevity may be useful for the understanding of molecular mechanisms implicated in age-related diseases. The molecular genetics of human longevity is largely unexplored in Latin American populations and other developing countries.

METHODS

To explore the possibility of an association of common polymorphisms in two candidate genes and longevity in Colombia, we analyzed two polymorphisms in apolipoprotein E (APOE) and angiotensin-converting enzyme (ACE) genes in a sample of 538 Colombian subjects (18-106 years), using previously validated PCR-based methodologies.

RESULTS

We found a significant decrease in ACE DD genotype (24 vs. 16%) between young and old subject groups (mean age: 45 vs. 77 years) (p = 0.03). The ACE DD genotype and D allele decrease was significant only in women. There were no differences for APOE polymorphism between young and old subjects.

CONCLUSIONS

Our results are compatible with the expected age-related decrease of ACE DD genotype. Future studies examining functional single nucleotide polymorphisms (SNPs) in the ACE gene and its correlation with serum ACE activity in the older subjects and their younger relatives in this sample are warranted.

Shorter telomeres are associated with mortality in those withAPOEϵ4 and dementia

OBJECTIVE

Reduced telomere length may be a marker of biological aging. We hypothesized that telomere length might thus relate to increased risk for dementia and mortality.

METHODS

This nested case-control study used stored leukocyte DNA from 257 individuals (mean age, 81.4 +/- 7.9 years; 64.6% female; 44.7% Hispanic, 33.5% non-Hispanic black, and 21.8% non-Hispanic white). Our assay used real-time polymerase chain reaction, with two separate reactions amplifying telomere sequence and reference single copy gene (ribosomal-protein-P0), providing a calculated telomere-to-single copy gene (T/S) ratio.

RESULTS

Mean telomere length was shorter among subjects dying during follow-up than in those surviving (0.453 +/- 0.211 vs 0.525 +/- 0.226 [+/- standard deviation]; p < 0.009). It was also shorter in those with Alzheimer's disease compared with control subjects (0.458 +/- 0.207 vs 0.516 +/- 0.229; p < 0.03). For participants with Alzheimer's disease, compared with those with the longest telomeres, the mortality odds ratio (OR) was 4.8 (95% confidence interval [CI], 1.7-13.8) in those with intermediate-length telomeres and 7.3 (95% CI, 2.4-22.0) in those with the shortest telomeres. The presence of an epsilon4 allele also increased the mortality OR, with an OR of 5.8 (95% CI, 1.3-26.4) for intermediate-length telomeres and an OR of 9.0 (95% CI, 1.9-41) for the shortest telomeres.

INTERPRETATION

Our findings suggest that leukocyte telomere length is related to both dementia and mortality and may be a marker of biological aging.

Dose-dependent retrograde facilitation of verbal memory in healthy elderly after acute oral lorazepam administration

RATIONALE

Retrograde facilitation (RF) refers to a paradoxical phenomenon in which recall of information presented before acute administration of agents generally associated with anterograde amnestic and sedative effects, such as benzodiazepines, is enhanced relative to a placebo condition. However, it is unclear whether this effect occurs in elderly individuals and if it is influenced by plasma drug levels, baseline cognitive function, or genetic factors such as the APOE e-4 allele, that may modulate drug-induced cognitive toxicity.

OBJECTIVES

To determine if acute oral doses of lorazepam (0.5 mg, 1 mg) produced RF in elderly individuals exposed to interference tasks, and the variables associated with RF.

MATERIALS AND METHODS

Sixty-four cognitively intact and highly educated (>12 years) older adults (mean age, 66.09 years) participated in a placebo-controlled double-blind crossover study. The Buschke Selective Reminding Test was used to assess RF and amnestic effects for verbal memory. Self-ratings of mood states were also obtained.

RESULTS

Lorazepam administration resulted in significant dose-dependent RF, i.e., better recall of pre-drug word lists compared to placebo [F(1,63)= 15.358; p<0.001 and F(1,63)= 46.163; p<0.001 for 0.5 and 1 mg lorazepam, respectively]. Also, more of the pre-drug words were recalled in the 1.0-mg-lorazepam condition relative to the 0.5-mg-lorazepam condition [F(1,63)=29.498; p<0.001]. In both the 0.5 and 1 mg lorazepam conditions, participants who exhibited high RF experienced significantly greater lorazepam-induced memory impairments over time [F(3,61)=2.901; p<0.05; F(3,61)=2.698; p<0.05; 0.5 and 1 mg lorazepam, respectively]. Also, in the 1-mg-lorazepam condition, participants who exhibited high RF reported significantly greater drowsiness relative to participants who showed less RF [t(62)=-2.521; p<0.05]. RF was not significantly associated with age, the APOE epsilon4 allele, years of education, global cognitive status, vocabulary scores, or a memory index score.

CONCLUSION

In healthy elderly, acute oral lorazepam administration resulted in dose-dependent RF, which was associated with greater anterograde amnestic and sedative effects.

Apolipoprotein gene E4 allele promoter polymorphisms as risk factors for Alzheimer's disease

Alzheimer's disease is a complex neurodegenerative disorder, characterized by progressive cognitive decline and distinct neuropathology. The apolipoprotein gene E4 allele (APOE 4) is a major risk factor for the disease. Promoter polymorphisms at -491 and -427 may also contribute to the risk. We examined the two polymorphisms in 178 Alzheimer's patients and 141 controls. The -491AA genotype was overrepresented among the patients (68 versus 54%, P=0.01). However, in patients who were APOE4 carriers, the -491AA genotype more than doubled the risk [odds ratio (OR)=2.5; 95% confidence interval (CI)=1.2-5.4], especially in combination with -427TT [odds ratio (OR)=3.3; 95% confidence interval (CI)=1.5-7.7]. Moreover, the -491A/-427T/APOE4/APOC1A haplotype was threefold higher for patients. These results contribute to the evidence that regulation of APOE4 expression modulates risk for Alzheimer's disease.

Apolipoprotein E Genotype and Mortality: Findings from the Cache County Study

OBJECTIVES

To evaluate the association between apolipoprotein E (apo E) epsilon4 and mortality, the population attributable risk for mortality with epsilon4, and relative contributions of cardiovascular disease (CVD) and Alzheimer's disease (AD).

DESIGN

Population-based cohort study.

SETTING

Community-based.

PARTICIPANTS

Permanent residents of Cache County, Utah, aged 65 and older as of January 1, 1995.

MEASUREMENTS

Participants were genotyped at the apo E locus using buccal-swab deoxyribonucleic acid. Cardiovascular health was ascertained using self- or proxy-report interviews at participants' residences. AD was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders criteria. Utah Department of Vital Statistics quarterly reports were reviewed to identify participants who died.

RESULTS

Crude evaluations showed nonsignificantly greater risk of death for epsilon2/2 (hazard ratio (HR)=1.66, 95% confidence interval (CI)=0.92-2.76) and epsilon3/4 (HR=1.11, 95% CI=0.97-1.26) genotypes and significantly greater risk for epsilon4/4 (HR=1.48, 95% CI=1.09-1.96). After adjustment for age, age(2), sex, and education, risks increased to 1.98 (95% CI=1.08-3.35), 1.28 (95% CI=1.12-1.46), and 2.02 (95% CI=1.47-2.71), respectively, compared with epsilon3/3 genotypes. Adjustment for presence of any CVD did not change the risk of death for epsilon3/4 and epsilon4/4. Adjustment for AD reduced the risk of death for epsilon3/4 (HR=1.13, 95% CI=0.99-1.30) and epsilon4/4 (HR=1.59, 95% CI=1.15-2.14). The population attributable risk of death for epsilon3/4 and epsilon4/4 genotypes combined is estimated at 9.6%.

CONCLUSION

These findings suggested that the epsilon2/2, epsilon3/4, and epsilon4/4 genotypes have greater early mortality risks. Further analyses showed that AD partially mediates the association between epsilon3/4, epsilon4/4, and death.

Survival Advantage of Hispanic Patients Initiating Dialysis in the United States Is Modified by Race

Differences in survival have been reported among ethnic groups in the general population. Whether these extend to patients with ESRD is unclear. Using national data, mortality risks of ethnic groups who began dialysis treatment in the United States between May 1, 1995, and July 31, 1997, were compared over 2 yr. Patients were classified as Hispanic or non-Hispanic and then subclassified by race forming six race-specific subgroups: Hispanic white, black, and other and non-Hispanic white, black, and other. Mortality rates for Hispanics compared with non-Hispanics were 19.2 versus 26 per 100 patient-years at risk for those with diabetes and were 14.7 versus 22.7 per 100 patient-years at risk for those without diabetes. For those with diabetes, adjusted mortality risks for Hispanics versus non-Hispanics were 30% lower (95% confidence interval [CI], 26 to 34%). In subgroup analysis, mortality risks for Hispanic whites and Hispanic blacks were 35% (95% CI, 31 to 39%) and 33% (95% CI, 12 to 48%) lower than non-Hispanic whites and were similar in magnitude to those of non-Hispanic blacks (32% lower; 95% CI, 29 to 35%) and non-Hispanic other (33% lower; 95% CI, 28 to 39%). Interestingly, mortality risks for Hispanic others were not significantly different from non-Hispanic whites. For those without diabetes, adjusted mortality risks for Hispanics versus non-Hispanics were 17% lower (95% CI, 9 to 23%), and subgroup analysis yielded similar patterns to those of individuals with diabetes. The survival advantage of Hispanic over non-Hispanic patients who receive chronic dialysis treatment in the United States is not consistent across subgroups and is modified by race. Cultural and genetic differences as well as variation in the access and delivery of care before and while on dialysis may account for these differences.

Preservation of cognitive and functional ability as markers of longevity

Longevity is a complex biological process for which the phenotypes have not been established. Preservation of cognitive and physical function may be important and preservation of these functions is, in part, inherited. We investigated the relation between rate of change in cognitive and functional abilities in probands and risk of death in their siblings. Probands were classified as showing no decline, slow, medium, or rapid rate of decline, based on the slope of change in cognitive and physical/functional factors over three or more assessments. Siblings of probands who did not decline on measures of memory, visuospatial/cognitive function or ADL skills were approximately half as likely to die as siblings of probands who had the most rapid decline. The reduction in risk of death in siblings of probands who did not decline in was primarily observed among siblings of probands who were older than 75 years, suggesting that genetic influences on life span may be greater at older ages. There was no association between probands' rate of change in language, IADL skills, upper or lower extremity mobility and risk of death in siblings. The results of the present study identify phenotypes associated with preserved cognitive and functional abilities which may serve as markers for longevity.

Genetic influences on life span and survival among elderly African-Americans, Caribbean Hispanics, and Caucasians

An investigation of the genetic influences on life span and survival was conducted among elderly African-Americans, Caribbean Hispanics, and Caucasians Medicare recipients (ages 65-104 years). Family history information on 13,161 parents and siblings was obtained. Heritability of life span varied by the age and by ethnic group being lowest for African-Americans. We recalculated the heritability coefficients for life span including only probands and their siblings, but the differences across ethnic groups persisted. In contrast the heritability of survival was more similar across ethnic groups but was similar to that for life span. Heritability coefficients for survival in probands and their siblings revealed little difference between ethnic groups and suggested that as much as 35% of the variation in survival may be genetically influenced. These results indicate that life span and survival are genetically influenced. Comparisons across generations and ethnic groups indicate that changes in environmental hygiene, social welfare, and health care systems are significant contributors to life span and survival, but genetic influences are also important. Identifying the genes associated with life span and survival will provide insight into how the genes interact with environment to influence aging in humans.

The APOE Gene and Differences in Life Expectancy in Europe

Common alleles of the apolipoprotein-E gene (APOE) are associated with different risks of ischemic heart disease, Alzheimer's disease, and other chronic conditions in European populations. Also, the APOE allele frequencies vary widely among European countries. We estimated the proportion of differences in mortality and differences in life span that are attributable to differences in APOE allele frequencies in Europe. Mortality rates by age, sex, and APOE genotype for six countries (Denmark, Finland, France, Italy, the Netherlands, and Sweden) were used to standardize mortality rates to the allele frequencies in Italy. Differences in APOE allele frequencies explain 12%-17% of the variation among these countries in mortality in people older than 65 years and 1%-2% of the variation in life span in those older than 65 years. Differences by genotype in mortality in people older than 15 years account for about 3.5% of the genetic contribution to the variation in life span in Denmark.

Mortality and apolipoprotein E in African-American, and White elders: an attempted replication

We have tried, with only partial success, to confirm findings in a recently reported study in this journal on the relationship of APOE genotype to mortality in community representative Hispanics (n = 659), Whites (n = 272), and African-Americans (n = 450), aged 65 and over, living in Northern Manhattan, New York. That study found that using proportional hazards models adjusted for sex and lipid levels, Hispanics and Whites with the E2/E3 genotype, but not African-Americans, had the lowest mortality risk. Those under age 75 had risks comparable to those over age 75, suggesting minimal survivor bias. Nearly 50% of the mortality risk associated with the APOE genotype appeared to act through heart disease, diabetes, and stroke. The current study of African-Americans (n = 1,083) and Whites (n = 915) aged 71 and over living in the more rural Southeastern US, found no protective effect of the E2/E3 genotype for either African-Americans or Whites. Among younger Whites (age 71-75), point estimates suggested that the E2/E3 genotype might be protective, but at a nonsignificant level; self-reported African-American race, but not genotype, was a risk factor for mortality in this age group. Neither lipid level nor health condition attenuated the effect of APOE genotype. Differences in findings may reflect issues of sampling, age, the relative distribution of the APOE alleles, or some other factor. Until such time as studies use truly representative samples and include younger ages, findings in this area must be treated with caution.

Apolipoprotein E polymorphisms and mortality in Italian type 2 diabetic patients

AIMS

To determine if apolipoprotein E polymorphism is associated with cardiovascular or all-cause mortality in Italian Type 2 diabetic patients.

METHODS

A prospective study of mortality in Type 2 diabetic patients (n = 433) as a function of apolipoprotein E phenotype, which was assessed at entry into the study. During follow up (10 years), 110 (25.4%) patients died of which 66 (15.2%) were the result of cardiovascular causes. Cause of death was established from death certificates and clinical records. The clinical status of the survivors was determined at the end of the study.

RESULTS

Apolipoprotein E polymorphisms were not associated with excess cardiovascular or all-cause mortality in the Italian Type 2 diabetic patients either in univariate or multivariate analyses. Age, duration of diabetes and glycated haemoglobin levels at entry were the primary determinants of premature mortality in the diabetic population.

CONCLUSIONS

Apolipoprotein E polymorphisms are not markers for premature mortality in Italian Type 2 diabetic patients. The impact of apolipoprotein E mutations may be attenuated by environmental factors, notably a healthier diet, in Italian patients.

Apolipoprotein E polymorphism and atherosclerosis

The relationship between apolipoprotein (apo) E and vascular disease has been the subject of a considerable amount of research. However, this relationship is far from clearly defined. This deficiency appears to be due to a multitude of factors. Among these are differences in ethnicity, age (and possibly gender), diagnostic criteria, and environmental factors (eg, diet and smoking) that have contributed to the contradictory findings. Several diseases and their treatment may also influence this relationship. There are also documented interactions between apo E genotypes and other genes or vascular risk factors. One possible clinically relevant application of identifying the apo E genotype could be to assess the response to a particular drug treatment. It may also be that apo E polymorphism will become a good predictor of vascular death (eg, from myocardial infarction or stroke) rather than an indicator of the risk of developing vascular disease but without an acute ischemic event. More research is required to define the place of apo E genotyping in the management of vascular disease in its various forms. Whatever the future brings, the evaluation of apo E genotypes will need to be rapid, cheap, and technically undemanding before this investigation becomes widely available and clinically relevant.

Apolipoproteins and aging: emerging mechanisms

One of the goals of modern medicine is to foster successful aging. In order to age successfully, one must accomplish two things: first, survive; and second, survive with good health and a sharp mind. In this discussion of apolipoproteins and aging, the focus will be on apolipoprotein E (apoE), a protein with three common isoforms, which has a large impact on longevity and successful aging. One variant of apoE (E4) is associated with increased risk for heart disease, stroke and Alzheimer's disease (AD). In addition, some of the potential mechanisms for the observed effects of apoE on aging will be discussed.