Dietary Astaxanthin: A Promising Antioxidant and Anti-Inflammatory Agent for Brain Aging and Adult Neurogenesis.

Decreased adult neurogenesis, or the gradual depletion of neural stem cells in adult neurogenic niches, is considered a hallmark of brain aging. This review provides a comprehensive overview of the intricate relationship between aging, adult neurogenesis, and the potential neuroregenerative properties of astaxanthin, a carotenoid principally extracted from the microalga Haematococcus pluvialis. The unique chemical structure of astaxanthin enables it to cross the blood-brain barrier and easily reach the brain, where it may positively influence adult neurogenesis. Astaxanthin can affect molecular pathways involved in the homeostasis, through the activation of FOXO3-related genetic pathways, growth, and regeneration of adult brain neurons, enhancing cell proliferation and the potency of stem cells in neural progenitor cells. Furthermore, astaxanthin appears to modulate neuroinflammation by suppressing the NF-κB pathway, reducing the production of pro-inflammatory cytokines, and limiting neuroinflammation associated with aging and chronic microglial activation. By modulating these pathways, along with its potent antioxidant properties, astaxanthin may contribute to the restoration of a healthy neurogenic microenvironment, thereby preserving the activity of neurogenic niches during both normal and pathological aging.

Association with Longevity of Phosphatidylinositol 3-Kinase Regulatory Subunit 1 Gene Variants Stems from Protection against Mortality Risk in Men with Cardiovascular Disease.

INTRODUCTION: Genetic variation in the phosphatidylinositol 3-kinase reregulatory subunit 1 gene (PIK3R1) is associated with longevity. OBJECTIVE: The aim of the study was to determine whether cardiovascular disease (CVD) affects this association. METHODS: We performed a longitudinal study of longevity-associated PIK3R1 single-nucleotide polymorphism rs7709243 genotype by CVD status in 3,584 elderly American men of Japanese ancestry. RESULTS: At baseline (1991-1993), 2,254 subjects had CVD and 1,314 did not. The follow-up until Dec 31, 2019 found that overall, men with a CVD had higher mortality than men without a CVD (p = 1.7 × 10-5). However, survival curves of CVD subjects differed according to PIK3R1 genotype. Those with longevity-associated PIK3R1 TT/CC had survival curves similar to those of subjects without a CVD (p = 0.11 for TT/CC, and p = 0.054 for TC), whereas survival curves for CVD subjects with the CT genotype were significantly attenuated compared with survival curves of subjects without a CVD (p = 0.0000012 compared with TT/CC, and p = 0.0000028 compared with TC). Men without CVD showed no association of longevity-associated genotype with life span (p = 0.58). Compared to subjects without any CVD, hazard ratios for mortality risk were 1.26 (95% CI, 1.14-1.39; p = 0.0000043) for CT subject with CVD and 1.07 (95% CI 0.99-1.17; p = 0.097) for CC/TT subjects with CVD. There was no genotypic effect on life span for 1,007 subjects with diabetes and 486 with cancer. CONCLUSION: Our study provides novel insights into the basis for PIK3R1 as a longevity gene. We suggest that the PIK3R1 longevity genotype attenuates mortality risk in at-risk individuals by protection against cellular stress caused by CVD.

Factor analysis of the Cognitive Abilities Screening Instrument: Kuakini Honolulu-Asia Aging Study.

OBJECTIVE: The Cognitive Abilities Screening Instrument (CASI) is a screening test of global cognitive function used in research and clinical settings. However, the CASI was developed using face validity and has not been investigated via empirical tests such as factor analyses. Thus, we aimed to develop and test a parsimonious conceptualization of the CASI rooted in cognitive aging literature reflective of crystallized and fluid abilities. DESIGN: Secondary data analysis implementing confirmatory factor analyses where we tested the proposed two-factor solution, an alternate one-factor solution, and conducted a χ2 difference test to determine which model had a significantly better fit. SETTING: N/A. PARTICIPANTS: Data came from 3,491 men from the Kuakini Honolulu-Asia Aging Study. MEASUREMENTS: The Cognitive Abilities Screening Instrument. RESULTS: Findings demonstrated that both models fit the data; however, the two-factor model had a significantly better fit than the one-factor model. Criterion validity tests indicated that participant age was negatively associated with both factors and that education was positively associated with both factors. Further tests demonstrated that fluid abilities were significantly and negatively associated with a later-life dementia diagnosis. CONCLUSIONS: We encourage investigators to use the two-factor model of the CASI as it could shed light on underlying cognitive processes, which may be more informative than using a global measure of cognition.

Astaxanthin as a Putative Geroprotector: Molecular Basis and Focus on Brain Aging.

In recent years, the scientific interest in natural compounds with geroprotective activities has grown exponentially. Among the various naturally derived molecules, astaxanthin (ASX) represents a highly promising candidate geroprotector. By virtue of the central polyene chain, ASX acts as a scavenger of free radicals in the internal membrane layer and simultaneously controls oxidation on the membrane surface. Moreover, several studies have highlighted ASX's ability to modulate numerous biological mechanisms at the cellular level, including the modulation of transcription factors and genes directly linked to longevity-related pathways. One of the main relevant evolutionarily-conserved transcription factors modulated by astaxanthin is the forkhead box O3 gene (FOXO3), which has been recognized as a critical controller of cell fate and function. Moreover, FOXO3 is one of only two genes shown to robustly affect human longevity. Due to its tropism in the brain, ASX has recently been studied as a putative neuroprotective molecule capable of delaying or preventing brain aging in different experimental models of brain damage or neurodegenerative diseases. Astaxanthin has been observed to slow down brain aging by increasing brain-derived neurotrophic factor (BDNF) levels in the brain, attenuating oxidative damage to lipids, protein, and DNA and protecting mitochondrial functions. Emerging data now suggest that ASX can modulate Nrf2, FOXO3, Sirt1, and Klotho proteins that are linked to longevity. Together, these mechanisms provide support for a role of ASX as a potential geroneuroprotector.

Reply by Authors - Re: Canadian Pediatrics Society position statement on newborn circumcision: a risk-benefit analysis revisited.

EDITORIAL.

New Horizons: Dietary protein, ageing and the Okinawan ratio.

Nutrition has profound effects on ageing and lifespan. Caloric restriction is the major nutritional intervention that historically has been shown to influence lifespan and/or healthspan in many animal models. Studies have suggested that a reduction in protein intake can also increase lifespan, albeit not as dramatically as caloric restriction. More recent research based on nutritional geometry has attempted to define the effects of nutrition on ageing over a broad landscape of dietary macronutrients and energy content. Such studies in insects and mice indicate that animals with ad libitum access to low-protein, high-carbohydrate diets have longest lifespans. Remarkably, the optimum content and ratio of dietary protein to carbohydrates for ageing in experimental animals are almost identical to those in the traditional diets of the long-lived people on the island of Okinawa.

Canadian Pediatrics Society position statement on newborn circumcision: a risk-benefit analysis revisited.

INTRODUCTION: The Canadian Pediatrics Society (CPS) recently released a position statement on early infant (newborn) male circumcision (EIMC). It concluded that since benefits do not exceed risks, circumcision should only be performed on boys in high-risk populations or circumstances. This contradicts recommendations by the American Academy of Pediatrics and the Centers for Disease Control and Prevention (CDC) whose policies each support more widespread implementation of EIMC. Here we review the CPS statement, particularly its risk-benefit analysis, to determine the basis for this disparity. MATERIALS AND METHODS: We performed a risk-benefit analysis based on relevant literature retrieved from PubMed reporting frequency of each condition, giving emphasis to data from meta-analyses and randomized controlled trials. RESULTS: Although the CPS recognized some of the benefits of EIMC, its inclusion of weak studies of adverse events led to these being over-estimated, greatly exceeding the figure of < 0.5% found in a recent large, technically robust, CDC study. The CPS under-estimated benefits by omitting balanitis, balanoposthitis, prostate cancer, some sexually transmitted infections and candidiasis, and failing to consider lifetime prevalence of urinary tract infections in uncircumcised males. In contrast, our more inclusive risk-benefit analysis found benefits exceed risks by approximately 100 to 1 and that lack of EIMC contributes to adverse medical conditions, some potentially fatal, in approximately half of uncircumcised males. CONCLUSIONS: The 2015 CPS position statement on EIMC is at odds with the evidence. The CPS conclusions stem from errors in its risk-benefit analysis. In light of our findings we recommend the CPS issue a revised statement.

FOXO3: A Major Gene for Human Longevity--A Mini-Review.

BACKGROUND: The gene FOXO3, encoding the transcription factor forkhead box O-3 (FoxO3), is one of only two for which genetic polymorphisms have exhibited consistent associations with longevity in diverse human populations. OBJECTIVE: Here, we review the multitude of actions of FoxO3 that are relevant to health, and thus healthy ageing and longevity. METHODS: The study involved a literature search for articles retrieved from PubMed using FoxO3 as keyword. RESULTS: We review the molecular genetics of FOXO3 in longevity, then current knowledge of FoxO3 function relevant to ageing and lifespan. We describe how FoxOs are involved in energy metabolism, oxidative stress, proteostasis, apoptosis, cell cycle regulation, metabolic processes, immunity, inflammation and stem cell maintenance. The single FoxO in Hydra confers immortality to this fresh water polyp, but as more complex organisms evolved, this role has been usurped by the need for FoxO to control a broader range of specialized pathways across a wide spectrum of tissues assisted by the advent of as many as 4 FoxO subtypes in mammals. The major themes of FoxO3 are similar, but not identical, to other FoxOs and include regulation of cellular homeostasis, particularly of stem cells, and of inflammation, which is a common theme of age-related diseases. Other functions concern metabolism, cell cycle arrest, apoptosis, destruction of potentially damaging reactive oxygen species and proteostasis. CONCLUSIONS: The mechanism by which longevity-associated alleles of FOXO3 reduce age-related mortality is currently of great clinical interest. The prospect of optimizing FoxO3 activity in humans to increase lifespan and reduce age-related diseases represents an exciting avenue of clinical investigation. Research strategies directed at developing therapeutic agents that target FoxO3, its gene and proteins in the pathway(s) FoxO3 regulates should be encouraged and supported.

Caloric restriction, caloric restriction mimetics, and healthy aging in Okinawa: controversies and clinical implications.

PURPOSE OF REVIEW: To examine the role of two nutritional factors implicated in the healthy aging of the Okinawans: caloric restriction; and traditional foods with potential caloric restriction-mimetic properties. RECENT FINDINGS: Caloric restriction is a research priority for the US National Institute on Aging. However, little is known regarding health effects in humans. Some caloric restriction-related outcomes, such as cause-specific mortality and lifespan, are not practical for human clinical trials. Therefore, epidemiological data on older Okinawans, who experienced a caloric restriction-like diet for close to half their lives, are of special interest. The nutritional data support mild caloric restriction (10-15%) and high consumption of foods that may mimic the biological effects of caloric restriction, including sweet potatoes, marine-based carotenoid-rich foods, and turmeric. Phenotypic evidence is consistent with caloric restriction (including short stature, low body weight, and lean BMI), less age-related chronic disease (including cardiovascular diseases, cancer, and dementia), and longer lifespan (mean and maximum). SUMMARY: Both caloric restriction and traditional Okinawan functional foods with caloric restriction-mimetic properties likely had roles in the extended healthspan and lifespan of the Okinawans. More research is needed on health consequences of caloric restriction and foods with caloric restriction-mimetic properties to identify possible nutritional interventions for healthy aging.

Body mass index and risk of death in Asian Americans.

OBJECTIVES: We investigated the association between body mass index (BMI) and mortality among Asian Americans. METHODS: We pooled data from prospective cohort studies with 20 672 Asian American adults with no baseline cancer or heart disease history. We estimated hazard ratios and 95% confidence intervals (CIs) with Cox proportional hazards models. RESULTS: A high, but not low, BMI was associated with increased risk of total mortality among individuals aged 35 to 69 years. The BMI was not related to total mortality among individuals aged 70 years and older. With a BMI 22.5 to < 25 as the reference category among never-smokers aged 35 to 69 years, the hazard ratios for total mortality were 0.83 (95% CI = 0.47, 1.47) for BMI 15 to < 18.5; 0.91 (95% CI = 0.62, 1.32) for BMI 18.5 to < 20; 1.08 (95% CI = 0.86, 1.36) for BMI 20 to < 22.5; 1.14 (95% CI = 0.90, 1.44) for BMI 25 to < 27.5; 1.13 (95% CI = 0.79, 1.62) for BMI 27.5 to < 30; 1.82 (95% CI = 1.25, 2.64) for BMI 30 to < 35; and 2.09 (95% CI = 1.06, 4.11) for BMI 35 to 50. Higher BMI was also related to increased cardiovascular disease and cancer mortality. CONCLUSIONS: High BMI is associated with increased mortality risk among Asian Americans.

Regional pulse wave velocities and their cardiovascular risk factors among healthy middle-aged men: a cross-sectional population-based study.

BACKGROUND: Both carotid-femoral (cf) pulse wave velocity (PWV) and brachial-ankle (ba) PWV employ arterial sites that are not consistent with the path of blood flow. Few previous studies have reported the differential characteristics between cfPWV and baPWV by simultaneously comparing these with measures of pure central (aorta) and peripheral (leg) arterial stiffness, i.e., heart-femoral (hf) PWV and femoral-ankle (fa) PWV in healthy populations. We aimed to identify the degree to which these commonly used measures of cfPWV and baPWV correlate with hfPWV and faPWV, respectively, and to evaluate whether both cfPWV and baPWV are consistent with either hfPWV or faPWV in their associations with cardiovascular (CV) risk factors. METHODS: A population-based sample of healthy 784 men aged 40-49 (202 white Americans, 68 African Americans, 202 Japanese-Americans, and 282 Koreans) was examined in this cross-sectional study. Four regional PWVs were simultaneously measured by an automated tonometry/plethysmography system. RESULTS: cfPWV correlated strongly with hfPWV (r = .81, P < .001), but weakly with faPWV (r = .12, P = .001). baPWV correlated moderately with both hfPWV (r = .47, P < .001) and faPWV (r = .62, P < .001). After stepwise regression analyses with adjustments for race, cfPWV shared common significant correlates with both hfPWV and faPWV: systolic blood pressure (BP) and body mass index (BMI). However, BMI was positively associated with hfPWV and cfPWV, and negatively associated with faPWV. baPWV shared common significant correlates with hfPWV: age and systolic BP. baPWV also shared the following correlates with faPWV: systolic BP, triglycerides, and current smoking. CONCLUSIONS: Among healthy men aged 40 - 49, cfPWV correlated strongly with central PWV, and baPWV correlated with both central and peripheral PWVs. Of the CV risk factors, systolic BP was uniformly associated with all the regional PWVs. In the associations with factors other than systolic BP, cfPWV was consistent with central PWV, while baPWV was consistent with both central and peripheral PWVs.

Implausibility of radical life extension in humans in the twenty-first century.

Over the course of the twentieth century, human life expectancy at birth rose in high-income nations by approximately 30 years, largely driven by advances in public health and medicine. Mortality reduction was observed initially at an early age and continued into middle and older ages. However, it was unclear whether this phenomenon and the resulting accelerated rise in life expectancy would continue into the twenty-first century. Here using demographic survivorship metrics from national vital statistics in the eight countries with the longest-lived populations (Australia, France, Italy, Japan, South Korea, Spain, Sweden and Switzerland) and in Hong Kong and the United States from 1990 to 2019, we explored recent trends in death rates and life expectancy. We found that, since 1990, improvements overall in life expectancy have decelerated. Our analysis also revealed that resistance to improvements in life expectancy increased while lifespan inequality declined and mortality compression occurred. Our analysis suggests that survival to age 100 years is unlikely to exceed 15% for females and 5% for males, altogether suggesting that, unless the processes of biological aging can be markedly slowed, radical human life extension is implausible in this century.

FOXO3 longevity genotype attenuates the impact of hypertension on cerebral microinfarct risk.

OBJECTIVE: The G -allele of FOXO3 SNP rs2802292 , which is associated with human resilience and longevity, has been shown to attenuate the impact of hypertension on the risk of intracerebral hemorrhage (ICH). We sought to determine whether the FOXO3 G -allele similarly attenuates the impact of hypertension on the risk of cerebral microinfarcts (CMI). METHODS: From a prospective population-based cohort of American men of Japanese ancestry from the Kuakini Honolulu Heart Program (KHHP) and Kuakini Honolulu-Asia Aging Study (KHAAS) that had brain autopsy data, age-adjusted prevalence of any CMI on brain autopsy was assessed. Logistic regression models, adjusted for age at death, cardiovascular risk factors, FOXO3 and APOE-ε4 genotypes, were utilized to determine the predictors of any CMI. Interaction of FOXO3 genotype and hypertension was analyzed. RESULTS: Among 809 men with complete data, 511 (63.2%) participants had evidence of CMI. A full multivariable model demonstrated that BMI [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.01-1.14, P  = 0.015) was the only predictor of CMI, while hypertension was a borderline predictor (OR 1.44, 95% CI 1.00-2.08, P  = 0.052). However, a significant interaction between FOXO3 G -allele carriage and hypertension was observed ( P  = 0.020). In the stratified analyses, among the participants without the longevity-associated FOXO3 G -allele, hypertension was a strong predictor of CMI (OR 2.25, 95% CI 1.34-3.77, P  = 0.002), while among those with the longevity-associated FOXO3 G -allele, hypertension was not a predictor of CMI (OR 0.88, 95% CI 0.51-1.54, P  = 0.66). CONCLUSION: The longevity-associated FOXO3 G -allele mitigates the impact of hypertension on the risk of CMI.

Novel protective effect of the FOXO3 longevity genotype on mechanisms of cellular aging in Okinawans.

The genetic association of FOXO3 genotypes with human longevity is well established, although the mechanism is not fully understood. We now report on the relationship of the FOXO3 longevity variant rs2802292 with telomere length, telomerase activity, FOXO3 expression, and inflammatory cytokine levels in men and women. In agreement with earlier work, the FOXO3 longevity variant conferred protection against telomere shortening of peripheral blood mononuclear cells from adults aged 55 years and older. This was accompanied by higher levels of telomerase activity in mononuclear cells for carriers of the longevity-associated FOXO3 G-allele of SNP rs2802292 (P = 0.015). FOXO3 mRNA expression increased slightly with age in both young (P = 0.02) and old (P = 0.08) G-allele carriers. Older female G-allele carriers displayed a modest decline in levels of pro-inflammatory cytokine IL-6 with age (P = 0.07). In contrast, older male G-allele carriers displayed an age-dependent increase in levels of anti-inflammatory cytokine IL-10 with age (P = 0.04). Thus, FOXO3 may act through several different pro-longevity mechanisms, which may differ by age and sex.

Circulating microRNA profile of long-lived Okinawans identifies novel potential targets for optimizing lifespan and health span.

Nonagenarians and centenarians serve as successful examples of aging and extended longevity, showcasing robust regulation of biological mechanisms and homeostasis. Given that human longevity is a complex field of study that navigates molecular and biological mechanisms influencing aging, we hypothesized that microRNAs, a class of small noncoding RNAs implicated in regulating gene expression at the post-transcriptional level, are differentially regulated in the circulatory system of young, middle-aged, and nonagenarian individuals. We sequenced circulating microRNAs in Okinawan males and females <40, 50-80, and >90 years of age accounting for FOXO3 genetic variations of single nucleotide polymorphism (SNP) rs2802292 (TT - common vs. GT - longevity) and validated the findings through RT-qPCR. We report five microRNAs exclusively upregulated in both male and female nonagenarians with the longevity genotype, play predictive functional roles in TGF-ß, FoxO, AMPK, Pi3K-Akt, and MAPK signaling pathways. Our findings suggest that these microRNAs upregulated in nonagenarians may provide novel insight into enhanced lifespan and health span. This discovery warrants further exploration into their roles in human aging and longevity.

Astaxanthin and meclizine extend lifespan in UM-HET3 male mice; fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate do not significantly affect lifespan in either sex at the doses and schedules used.

In genetically heterogeneous (UM-HET3) mice produced by the CByB6F1 × C3D2F1 cross, the Nrf2 activator astaxanthin (Asta) extended the median male lifespan by 12% (p = 0.003, log-rank test), while meclizine (Mec), an mTORC1 inhibitor, extended the male lifespan by 8% (p = 0.03). Asta was fed at 1840 ± 520 (9) ppm and Mec at 544 ± 48 (9) ppm, stated as mean ± SE (n) of independent diet preparations. Both were started at 12 months of age. The 90th percentile lifespan for both treatments was extended in absolute value by 6% in males, but neither was significant by the Wang-Allison test. Five other new agents were also tested as follows: fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate. None of these increased lifespan significantly at the dose and method of administration tested in either sex. Amounts of dimethyl fumarate in the diet averaged 35% of the target dose, which may explain the absence of lifespan effects. Body weight was not significantly affected in males by any of the test agents. Late life weights were lower in females fed Asta and Mec, but lifespan was not significantly affected in these females. The male-specific lifespan benefits from Asta and Mec may provide insights into sex-specific aspects of aging.

Body-mass index and mortality among 1.46 million white adults.

BACKGROUND: A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain. METHODS: We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58). RESULTS: The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up. CONCLUSIONS: In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.

Proteomic basis of mortality resilience mediated by FOXO3 longevity genotype.

FOXO3 is a ubiquitous transcription factor expressed in response to cellular stress caused by nutrient deprivation, inflammatory cytokines, reactive oxygen species, radiation, hypoxia, and other factors. We showed previously that the association of inherited FOXO3 variants with longevity was the result of partial protection against mortality risk posed by aging-related life-long stressors, particularly cardiometabolic disease. We then referred to the longevity-associated genotypes as conferring "mortality resilience." Serum proteins whose levels change with aging and are associated with mortality risk may be considered as "stress proteins." They may serve as indirect measures of life-long stress. Our aims were to (1) identify stress proteins that increase with aging and are associated with an increased risk of mortality, and (2) to determine if FOXO3 longevity/resilience genotype dampens the expected increase in mortality risk they pose. A total of 4500 serum protein aptamers were quantified using the Somalogic SomaScan proteomics platform in the current study of 975 men aged 71-83 years. Stress proteins associated with mortality were identified. We then used age-adjusted multivariable Cox models to investigate the interaction of stress protein with FOXO3 longevity-associated rs12212067 genotypes. For all the analyses, the p values were corrected for multiple comparisons by false discovery rate. This led to the identification of 44 stress proteins influencing the association of FOXO3 genotype with reduced mortality. Biological pathways were identified for these proteins. Our results suggest that the FOXO3 resilience genotype functions by reducing mortality in pathways related to innate immunity, bone morphogenetic protein signaling, leukocyte migration, and growth factor response.

Vascular endothelial growth factor receptor 1 gene (FLT1) longevity variant increases lifespan by reducing mortality risk posed by hypertension.

Longevity is written into the genes. While many so-called "longevity genes" have been identified, the reason why particular genetic variants are associated with longer lifespan has proven to be elusive. The aim of the present study was to test the hypothesis that the strongest of 3 adjacent longevity-associated single nucleotide polymorphisms - rs3794396 - of the vascular endothelial growth factor receptor 1 gene, FLT1, may confer greater lifespan by protecting against mortality risk from one or more adverse medical conditions of aging - namely, hypertension, coronary heart disease (CHD), stroke, and diabetes. In a prospective population-based longitudinal study we followed 3,471 American men of Japanese ancestry living on Oahu, Hawaii, from 1965 until death or to the end of December 2019 by which time 99% had died. Cox proportional hazards models were used to assess the association of FLT1 genotype with longevity for 4 genetic models and the medical conditions. We found that, in major allele recessive and heterozygote disadvantage models, genotype GG ameliorated the risk of mortality posed by hypertension, but not that posed by having CHD, stroke or diabetes. Normotensive subjects lived longest and there was no significant effect of FLT1 genotype on their lifespan. In conclusion, the longevity-associated genotype of FLT1 may confer increased lifespan by protecting against mortality risk posed by hypertension. We suggest that FLT1 expression in individuals with longevity genotype boosts vascular endothelial resilience mechanisms to counteract hypertension-related stress in vital organs and tissues.

Weak Social Networks in Late Life Predict Incident Alzheimer's Disease: The Kuakini Honolulu-Asia Aging Study.

BACKGROUND: We assessed 10-year longitudinal associations between late-life social networks and incidence of all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VaD) in Japanese-American men. METHODS: We prospectively analyzed, from baseline (1991-1993) through 1999-2000, 2636 initially nondemented Kuakini Honolulu-Asia Aging Study participants who remained dementia-free during the first 3 years of follow-up. Global cognition was evaluated by the Cognitive Abilities Screening Instrument (CASI); depressive symptoms by the 11-item Center for Epidemiologic Studies Depression (CES-D) Scale; and social networks by the Lubben Social Network Scale (LSNS). Median split of LSNS scores defined weak/strong social network groups. A panel of neurologists and geriatricians diagnosed and classified dementia; AD and VaD diagnoses comprised cases in which AD or VaD, respectively, were considered the primary cause of dementia. RESULTS: Median (range) baseline age was 77 (71-93) years. Participants with weak (LSNS score ≤29) versus strong (>29) social networks had higher age-adjusted incidence (in person-years) of ACD (12.6 vs. 8.7; p = .014) and AD (6.7 vs. 4.0; p = .007) but not VaD (2.4 vs. 1.4; p = .15). Kaplan-Meier curves showed a lower likelihood of survival free of ACD (log-rank p < .0001) and AD (p = .0006) for men with weak networks. In Cox proportional hazards models adjusting for age, education, APOE ɛ4, prevalent stroke, depressive symptoms, and CASI score (all at baseline), weak networks predicted increased incidence of ACD (hazard ratio [HR] = 1.52, p = .009) and AD (HR = 1.67, p = .014) but not VaD (p > .2). CONCLUSION: Weak social networks may heighten the risk of dementia and AD, underscoring the need to promote social connectedness in older adults.