Social Environment And Biomarkers Of Aging Study Research Articles

Dose-Responsive Impacts of Social Frailty on Intrinsic Capacity and Healthy Aging among Community-Dwelling Middle-aged and Older Adults: Stronger Roles of Social Determinants over Biomarkers.

The intricate relationship between social determinants, e.g., social frailty, biomarkers and healthy aging remains largely unexplored, despite the potential for social frailty to impact both intrinsic capacity (IC) and functional ability in the aging process. Retrospective longitudinal cohort study. Participants aged 50+ years from the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan, stratified into three age groups: 50-64, 65-74 and 75+. Social frailty was defined based on a score derived from four domains: exclusion from general resources, social resources, social activity, and fulfillment of basic social needs. The scores were categorized as score=0 (no social frailty), 1 (social pre-frailty), and 2+ (social frailty). Multivariable logistic regression and Cox proportional hazard models were employed to examine the dose-responsive relationship between social frailty, low IC, functional and psychological health, and mortality. Of 1015 study participants, 24.9% and 7.9% were classified as social pre-frailty and social frailty, respectively. No significant differences were observed in most biomarkers between those with social frailty and those without. A dose-responsive relationship was found between social frailty and increased risk of low IC (social pre-frailty: aOR 2.20 [95% CI 1.59-3.04]; social frailty: 5.73 [3.39-9.69]). Similar results were found for functional and psychological health. However, no significant association between social frailty and all-cause mortality was found at the 4-year follow-up (social pre-frailty: aHR 1.52 [95% CI 0.94-2.43]; social frailty: 1.59 [0.81-3.09]). The significant association between social frailty and low IC, functional limitations, cognitive declines, and depressive symptoms underscores the pressing need for research on intervention strategies to enhance healthy aging in the lifespan course.

Sex-specific impacts of social isolation on loneliness, depressive symptoms, cognitive impairment, and biomarkers: Results from the social environment and biomarker of aging study

ObjectivesTo investigate sex-specific associations between social isolation and psychological outcomes and biomarkers among community-dwelling middle-aged and older adults using a nationally representative population-based cohort study. MethodsData from 757 participants from the Social Environment and Biomarkers of Aging Study (SEBAS) were retrieved for analysis, and all participants were stratified by sex. The associations between social isolation and psychological outcomes (loneliness, depressive symptoms, and cognitive impairment) at the 4-year follow-up were examined by multivariate logistic regression models, and associations between social isolation and biomarkers at the 4-year follow-up were examined by multivariate generalized linear models (GLMs). ResultsFor men, social isolation was not associated with the development of loneliness. However, being married (adjusted odds ratio (aOR) 0.32 [95% confidence interval (CI) 0.13-0.74], p<0.001) was associated with a lower risk of loneliness, indicating potential protective effects of marriage for men. On the other hand, social isolation was associated with a 2-fold higher risk of loneliness in women (aOR 2.26 [1.01-5.09], p<0.001). Social isolation was not associated with depressive symptoms after adjusting for other demographics. For men, being married (aOR 0.51 [0.26-0.99], p<0.05) or having good self-reported health (aOR 0.44 [0.21-0.92], p<0.05) was protective against depressive symptoms. For women, only good self-reported health (aOR 0.30 [0.13-0.70], p<0.01) provided protective effects against depressive symptoms. Similarly, other demographic factors (being married and having a higher educational level) but not social isolation were associated with lower risks of cognitive impairment. No significant associations were noted between social isolation and selected biomarkers. ConclusionsSex-different associations between social isolation and loneliness were noted; the effects of demographic factors, such as being married, self-reported health status, and high education levels, on subsequent loneliness, depression, and cognitive function were also sex-different. Further intervention studies are needed to explore sex-specific approaches to deal with the interplay of social isolation, loneliness, psychological outcomes and other demographic factors.

Biological Features of the Outcome-Based Intrinsic Capacity Composite Scores From a Population-Based Cohort Study: Pas de Deux of Biological and Functional Aging.

IntroductionThis study aims to develop and validate an integrative intrinsic capacity (IC) scoring system, to investigate its associations with a wide spectrum of biomarkers and to explore the predictive value of the integrative IC score on 4-year mortality among community dwelling people aged 50 years and older.MethodsWe included 839 adults aged ≥50 years from the Social Environment and Biomarkers of Aging Study (SEBAS) and randomly divided them into derivation and validation cohorts to develop the IC scoring system. The multivariate logistic regression model was used to weight each subdomain (locomotion, sensory, vitality, psychological, and cognition) of IC according to its association with impairments in instrumental activities of daily living (IADL) and to construct the integrative IC score. Age-related biomarkers and genetic markers were compared between IC groups by ordinal logistic regression. A Cox proportional hazard model was used to examine the association between IC and mortality, and subgroup analysis was used to assess the robustness of the results among participants aged 60 years and older.ResultsA 12-score IC scoring system (AUROC = 0.83; Hosmer–Lemeshow goodness-of-fit test p = 0.17) was developed, and higher scores indicated better intrinsic capacity. High interleukin (IL)-6, high E-selectin, low serum albumin and low folate were significantly associated with low IC in the whole sample. However, high IL-6, low serum albumin, low folate, high allostatic load, and APOE ε4 genotype were significantly associated with low IC in those aged 60 years old and older. Compared to the high IC group, the low IC group was significantly associated with all-cause mortality (HR: 2.50, 95% CI: 1.22–5.11, p = 0.01 for all participants; HR 2.19, 95% CI 1.03–4.64, p = 0.04 for participants aged 60 years and older).ConclusionsThe conceptually proposed IC can be easily transformed into a scoring system considering different weights of individual subdomains, which not only predicts mortality but also suggests different pathophysiologies across the life course of aging (inflammation, nutrition, stress, and ApoE4 genotype). An intervention study is needed using the composite IC score to promote healthy aging and determine the underlying pathophysiology.

Differential moderation effects of ApoE and 5-HTTLPR genotypes on social vulnerability in predicting mortality among community-dwelling middle-aged and older adults: a nationwide population-based study.

Aging is a dynamic complex process involving social vulnerability over time. The social vulnerability index (SVI) was developed that predicted adverse health outcomes. This study examined effects between SVI status and two genotypes, apolipoprotein E (ApoE) and Serotonin transporter genotyping (5-HTTLPR), on all-cause mortality. Data from the Social Environment and Biomarkers of Aging Study (SEBAS) were obtained, and SVI was constructed using 32 self-reported items of social determinants. Data from 985 participants (age: 65.73 ± 9.47 years, 54.62% males) were obtained for analysis, and the median SVI was 0.35 (IQR 0.29–0.42) with a near normal distribution. Participants with a higher SVI were more likely to be women and have poor cognitive function, more depressive symptoms and poor physical function. Adjusted for age and sex, each incremental deficit in SVI was associated with a 12% increase in mortality risk (HR: 1.12, 95% CI: 1.04–1.20, p = 0.002). An interaction was found between ApoE and SVI but not 5-HTTLPR. The strata-specific hazard ratio confirmed that associations between SVI and mortality was only in non-ε4 carriers (HR: 1.15, 95% CI: 1.07–1.24, p < 0.001), and SVI did not significantly predict mortality among ε4 carriers (HR: 0.84, 95% CI: 0.65–1.10). Differential SVI effects on mortality among middle-age and older adults were identified. In conclusion, a higher SVI was associated with all-cause mortality among middle-aged and older adults, and the association was moderated by ApoE genotypes but not 5-HTTLPR. Further study is needed to evaluate the clinical efficacy of healthy aging intervention programs considering gene-environment interactions and social vulnerability.

Age and sex differences in associations between self-reported health, physical function, mental function and mortality

ObjectivesTo explore how age and sex affect the impacts of self-rated health, self-reported physical activities, physical function, and depressive symptoms on long-term mortality among community-dwelling middle-aged and older adults using a nationally representative population-based cohort study. MethodsData from 1550 study participants from the Social Environment and Biomarkers of Aging Study (SEBAS) were retrieved for analysis, and all participants were divided into four groups based on their age and gender. Middle aged participants were aged 53 to 64 years, and elderly subjects were ≥ 65 years old. Multivariate logistic regression models were applied to investigate the associations between age, sex, and self-reported disabilities of physical activities, physical function (activities of daily living (ADL) and instrumental activities of daily living (IADL) and depression. ResultsAlthough the self-reported health status was similar across different age- and sex-stratified subgroups, older women were at the highest risk in self-reported difficulty with physical activities (aOR 2.58 [1.55-4.28]) and difficulty with IADL (aOR 3.32 [2.20-5.03]) compared to men. After adjusting for living arrangement, residence locale, education levels, occupation, socioeconomic status, self-reported health, multimorbidity, impairments in daily activities, and depressive symptoms, older men were found to display the highest risk of mortality (aHR 2.06 [95% CI 1.45-2.93]). ConclusionsAlthough self-reported health was similar across different age and sex stratified subgroups, women (particularly older women) are significantly more likely to have worse physical and functional health than men. After adjusting for all confounding factors, men are at substantially greater risk for mortality despite reporting better health and functional performance.

PIH16 - Age and Gender Differences in Self-Reported Physical, Functional, and Mental Health in Taiwan

To understand how age and gender may impact physical, functional, and mental health are critical in formulating sophisticated personalized care plan, particularly in the aging society. Previous studies have shown that women may have more disabilities in physical measures than men, but how other health-related measures were influenced by both gender and age was not further studied. This study thus aimed to investigate the self-reported physical, functional, and mental health among different age-gender groups in Taiwan. Data of 1550 study subjects from the Social Environment and Biomarkers of Aging Study (SEBAS), Taiwan were retrieved for analysis and all subjects were divided into four groups based on their age (middle aged: 53 to 64, the elderly: 65 and above) and gender. Multiple logistic regression models were adopted to investigate the associations between gender and self-reported disabilities of physical function, daily activity disabilities (activities of daily living, or ADL, and instrumental activities of daily living, or IADL) and depression. The adjusted multiple logistic regression models presented elder women were at the highest risk in self-reported difficulties of physical movement (aOR 6.59 [4.10-10.59], p<0.01) and difficulties of IADL (aOR 7.76 [4.63-12.98], p<0.01) compared to middle-aged men. This association was also perceived in the elderly subgroup, in which women were associated with a 2-fold increase in risk of self-reported difficulties of physical movement (aOR 2.69 [1.62-4.48], p<0.01) and a 3-fold increase in risk of an IADL disability (aOR 3.43 [2.25-5.25], p<0.01). This study revealed both middle-aged and elderly women were significantly more likely to have worse self-reported physical and functional health than men in the same age group in Taiwan.

General cognitive status among Baby boomers and pre-boomers in Taiwan: the interplay between mid-life socioeconomic status and city residence

BackgroundThis study seeks to assess the interaction between mid-life socioeconomic status (SES) and city residence on the cognitive status of Baby Boomers and pre-Boomers in Taiwan, a non-Western society with a distinct cultural and family context, taking apolipoprotein E (APOE) gene polymophism and life stressors into consideration.MethodsThe data used was from the Social Environment and Biomarkers of Aging Study (SEBAS) collected in Taiwan during 2006, this involved 1245 individuals from 23 communities and used multilevel regression. General cognitive status was assessed by ten questions via personal interviews. The questions were part of the Short Portable Mental Status Questionnaire, a 10-item free-recall and immediate recall test. Mid-life SES was defined by education and major mid-life occupation of the participant and/or their partner.ResultsMid-life SES was positively associated with cognitive status among both Baby Boomers and pre-Boomers, even after adjusting for APOE polymorphism and stressor covariates. For Baby Boomers, city residents were more likely than town residents to show better cognition (β = 1.47, p < 0.01) and an interaction effect between mid-life SES and city residence was observed (β = −2.12, p < 0.01). While both the Baby Boomer and pre-Boomer cohorts who lived with a partner were reported better cognition, the effects of depressive symptoms and ethnicity differed by cohort.ConclusionsHaving a high level of mid-life SES and living with a partner are associated with better cognition for both cohort groups. An interplay effect between mid-life SES and place of residence on cognition was only found for Baby Boomers. On the other hand, being psychologically depressed was associated with poorer cognition among pre-Boomers. These results underscore the specific roles of mid-life SES, city residence, and life stressors with regard to the cognitive status of Baby Boomers and pre-Boomers in Taiwan.

Obesity, Apolipoprotein E ε4, and Difficulties in Activities of Daily Living Among Older Adults: a 6-Year Follow-up Study.

Obesity has been associated with increased physical limitations among older adults, although few studies have adjusted for important covariates. There is limited information about the relationship between apolipoprotein E (APOE) polymorphisms and physical limitations, and the findings have been inconsistent. This study examined the longitudinal associations of obesity and APOE ε4 with difficulties in activities of daily living (ADLs) over a 6-year follow-up period controlling for multiple covariates. Data were analyzed from the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan collected in 2000 and 2006, involving a cohort of 639 participants (mean age=66). Body mass index (BMI) was used to define obesity at a baseline, and the APOE genotype was classified into an APOE ε4 carrier and non-carrier status. The combination of basic and instrumental activities of daily living (ADLs and IADLs) was used to define impaired ADLs. APOE ε4 carriers had greater difficulties in combined ADLs (incident rate ratio; IRR=1.87, 95% CI=1.40-2.51) than non-carriers. Obese but not overweight adults had greater difficulties in activities of daily living (IRR=1.59, 95% CI=1.20-2.10) compared with the normal/underweight group. Obese older adults without APOE ε4 had greater subsequent difficulties in ADLs than non-obese non-carriers. Among APOE ε4 carriers, obesity was not a significant risk factor for the development of impaired ADLs in older adults, indicating an interaction between genotype and obesity. The interaction between genotype and obesity phenotype adds new information about the determinants of physical impairment.

DOES LOWER SUBJECTIVE SOCIAL STATUS YIELD RISKIER BIOMARKER PROFILES?

Both objective and, more recently, subjective measures of low social status have been linked to poor health outcomes. It is unclear, however, through which precise physiological mechanisms such standing may influence health, although it has been proposed that those of lower status may have biomarker profiles that are more dysregulated (and hence pose a greater risk for poorer health). The main objective of this study was to investigate whether lower subjective social standing is associated with riskier neuroendocrine biomarker profiles. Data were from the Social Environment and Biomarkers of Aging Study (SEBAS), a nationally representative survey of Taiwanese men and women (ages 54-91) conducted in Taiwan in 2000. Five neuroendocrine markers (cortisol, dehydroepiandrosterone sulphate (DHEAS), adrenaline, noradrenaline and dopamine) were analysed both separately and collectively in an index termed neuroendocrine allostatic load (NAL) in relation to status - both self-reported and as measured through objective socioeconomic status (SES) indicators. For the biomarker DHEAS, some connection was found between its levels and the measures of status, but for the other markers and the NAL index almost no connection was found. The overall negative finding of this paper would be further supported with more and different measures of neuroendocrine system function and a reordering of the subjective social status questions in the survey such that the one probing about status in the community (that has no prompt) was asked before the one probing about status in all of Taiwan (which has a SES prompt).

Cohort Profile: The Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan.

The Social Environment and Biomarkers of Aging Study (SEBAS) is a nationally representative longitudinal survey of Taiwanese middle-aged and older adults. It adds the collection of biomarkers and performance assessments to the Taiwan Longitudinal Study of Aging (TLSA), a nationally representative study of adults aged 60 and over, including the institutionalized population. The TLSA began in 1989, with follow-ups approximately every 3 years; younger refresher cohorts were added in 1996 and 2003. The first wave of SEBAS, based on a sub-sample of respondents from the 1999 TLSA, was conducted in 2000. A total of 1023 respondents completed both a face-to-face home interview and, several weeks later, a hospital-based physical examination. In addition to a 12-h (7 pm-7 am) urine specimen collected the night before and a fasting blood specimen collected during the examination, trained staff measured blood pressure, height, weight and waist and hip circumferences. A second wave of SEBAS was conducted in 2006 using a similar protocol to SEBAS 2000, but with the addition of performance assessments conducted by the interviewers at the end of the home interview. Both waves of SEBAS also included measures of health status (physical, emotional, cognitive), health behaviours, social relationships and exposure to stressors. The SEBAS data, which are publicly available at [http://www.icpsr.umich.edu/icpsrweb/NACDA/studies/3792/version/5], allow researchers to explore the relationships among life challenges, the social environment and health and to examine the antecedents, correlates and consequences of change in biological measures and health.

Stress Responsive Biochemical Anabolic/Catabolic Ratio and Telomere Length in Older Adults

It has been hypothesized that chronic psychological stress is associated with shorter telomere length; however, the mechanisms that link stress and telomere length are not well understood. To examine the interplay between biochemical factors related to stress arousal and cellular aging, we investigate the association between anabolic/catabolic (A/C) imbalance and leukocyte telomere length (LTL) in the Social Environment and Biomarkers of Aging Study (SEBAS), conducted in Taiwan (N = 925). SEBAS participants aged 54 and older (mean age 68.3) with values for two anabolic hormones (serum dehydroepiandrosterone sulfate [DHEAS] and insulin growth factor [IGF]-1), four catabolic hormones (cortisol, epinephrine, norepinephrine, and interleukin-6 [IL-6]), and LTL were examined. We found that high IL-6 was associated with short LTL (≤ 0.88 T/S ratio; odds ratio [OR] 1.41, 95% confidence interval [CI] = 1.04–1.92). Neither DHEAS/cortisol nor IGF-1/cortisol ratio was associated with telomere length; however, a high A/C imbalance summary score was associated with greater odds of having a short LTL relative to long LTL (OR 1.19, 95% CI = 1.05–1.35). These results indicate that our A/C imbalance score, defined by several anabolic and catabolic biochemical factors, may be one mechanism through which psychological stress is associated with short LTL and possibly cellular senescence.

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.

Functional impairment but not metabolic syndrome is associated with depression in older Taiwanese: results from the Social Environment and Biomarkers of Aging Study.

This study examined the association of metabolic syndrome, metabolic disorders and functional impairment with depression in older (≥54 years) adults. A cross-sectional study. Data of this study were from the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan (2000). A national representative sample of persons 54 years of age or older in Taiwan (N = 1023). Results showed that the presence of any number of metabolic disorders without functional impairment was not associated with depression. However, the presence of functional impairment regardless of the number of metabolic disorder was associated with a significantly higher risk of depression after adjusting for confounding factors (OR = 5.13, 95% CI = 2.13-12.36) (p<0.05). The presence of a basic Activities of Daily Living (ADL) dependency was significantly associated with a 1.45 times higher likelihood of depression (OR = 1.45, 95% CI = 1.17-1.79) (p<0.05). Results suggest that functional impairment, but not metabolic syndrome or metabolic disorders, is associated with depression in older adults. Metabolic syndrome/disorders do not necessarily affect patient's psychological health unless it is accompanied with functional impairment.

Diabetes mellitus and functional impairment in Taiwanese older men and women

Type 2 diabetes mellitus is strongly related to many kinds of functional impairment, even after adjusting for demographic and comorbid conditions. The current study examined sex differences in the relationships between Type 2 diabetes mellitus and functional impairment in an Asian population sample. Data were obtained from a national survey, the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan. A total of 652 older adults aged ≥65 years were included in the study. Pearson's χ 2-test and multiple logistic regression analysis were used to examine the relationships between diabetes and functional impairments in older men and women. The reported numbers of impairments were significantly higher in women, in those aged ≥75 years, and in those with diabetes. There were sex and age differences in the relationships between diabetes and functional difficulties. Even after adjustment for age, education, and co-morbid conditions, men with diabetes were about four times more likely to have difficulties related to self-care, and women with diabetes were about two to three times more likely to have difficulties related to higher functioning than their non-diabetic counterparts. Sex differences should be considered when understanding the relationships between diabetes and functional impairments in older adults.

Apolipoprotein E Genotype and Risk of Developing Physical Limitations in Elderly People

To the Editor: Apolipoprotein E (APOE) gene is one of the genes with a huge impact on longevity and successful aging. The APOE polymorphism has been associated with lipid or cognitive disorders, which may result in cardiovascular disease or Alzheimer’s disease.1 In older adults, stroke and cognitive impairment are all risk factors for physical disability. Thus more researches have been conducted to examine whether the APOE genotype is independently associated with physical limitations in the older population. While these studies 2–5 do improve our knowledge on the relationship between APOE gene and physical function in older adults, no attention has been paid to investigating the role of this gene in the development of functional decline at different stages. The progressive decline of physical function in older adults usually begins with the limitation of mobility function, continues to deteriorate into difficulty in coping with complex household works, and finally results in inability to complete self-care tasks.6 We conducted a prospective nested case-control study of genetic variation in the APOE gene and risk of deterioration in physical functioning in Taiwan, with a particular interest in the transitions of mobility, Instrumental Activities of Daily Living (IADL), and Activities of Daily Living (ADL) decline. Samples were from 924 study participants of the Social Environment and Biomarkers of Aging Study (SEBAS) in 2000.7 SEBAS included an in-home interview and a physical examination at the hospital. The in-home interview collected information on self-reports of physical limitations, demographic and social variables, and cognitive measures. Mobility includes 9 tasks involving general mobility function of upper and lower extremities. IADL covers six tasks involving living environment. ADL incorporates six personal care tasks. Mobility decline was defined as having no difficulty in all 21 tasks in 2000 but experiencing difficulty in at least one of the 9 mobility tasks in 2003. IADL decline was defined as having difficulty in at least one mobility task but no difficulty in all ADL and IADL tasks in 2000, but experiencing difficulty in at least one mobility and one IADL task but no difficulty in all ADL tasks in 2003. ADL decline was defined as having difficulty in at least one mobility and one IADL task but no difficulty in all ADL tasks in 2000, and experiencing difficulty in at least one mobility, one IADL, and one ADL task in 2003. The APOE genotyping was conducted using DNA extract obtained from whole blood. During the three years of follow-up, there were 91, 79, and 35 participants identified as having mobility, IADL, and ADL decline, respectively. For each subject with mobility, IADL, or ADL decline, one control subject without the specific decline was matched for age and sex. For example, one subject with only mobility difficulty in both the 2000 and the 2003 interviews was age- and sex- matched to the subject with IADL decline. Odds ratios (ORs) for subjects carrying e2 or e4 allele were estimated using conditional logistic regression adjusting for risk factors relevant to functional decline,8,9 including body mass index (BMI), heart disease, stroke, arthritis, cognitive impairment, and physical activity. Updated information of these covariates obtained from the 2003 interview was used in the adjusted models. Because physical function of cases at baseline had not deteriorated, the prevalence of disability-related diseases and factors including BMI, cognitive impairment, and physical activity was similar and tested without statistically significant differences between cases and controls. The distribution of all sixAPOE genotypes (e2/e2, e2/e3, e2/e4, e3/e3, e3/e4, and e4/e4) and frequencies of the three APOE alleles (e2, e3, and e4) were statistically insignificant between cases with controls for all three groups. Table 1 shows the risks of developing mobility, IADL, or ADL limitations for older adults with the e2 or e4 allele. The presence of APOEe2 or e4 allele was not related to the declines of physical functioning. Table 1 Associations between APOE alleles and risk of mobility, IADL, or ADL decline This lack of association is in agreement with findings from three similar studies using ADL tasks, 3 a mobility task only, 10 or a combination of mobility, IADL, and ADL as the measures of physical limitations. 4 The e4 allele has been linked with decreased longevity through developing cognitive impairment and cardiovascular disease, whereas the e2 allele increases longevity and promotes successful aging. 1 Although APOE plays an important role in aging process, both e2 and e4 alleles, based on our study results, do not have a direct link with the decline of physical function at different stages. It is possible that APOE may affect physical function indirectly through cognitive impairment and cardiovascular disease, and the association disappears when cardiovascular disease and cognitive function are all considered.

Apolipoprotein E polymorphism, life stress and self-reported health among older adults

Objective:To examine the association of self-reported health (SRH) with the apolipoprotein E (APOE) gene, life stress, and sociobehavioural factors in adults aged 55 and over.Design:Secondary analysis of data from the...

Neuroendocrine biomarkers, social relations, and the cumulative costs of stress in Taiwan

Allostatic load (AL) is thought to represent the physiological toll that builds up over the life course as a consequence of the body's response to stress. An important aim of this paper is to test this widely held—but little investigated—understanding of what AL represents. More specifically, using the Social Environment and Biomarkers of Aging Study (SEBAS), a nationally representative survey of Taiwan conducted in year 2000, this paper scrutinizes the connection between stressful life histories and neuroendocrine allostatic load (NAL). Stressful life histories are operationalized through the use of two sets of indicators: one set makes use of respondents’ subjective interpretations of various life domains and the other makes use of non-subjective data about conditions that are expected to be stressful (e.g., widowhood, living alone, and low education). NAL is an index of four neuroendocrine biomarkers (cortisol, dehydroepiandrosterone sulfate (DHEAS), epinephrine, and norepinephrine) collected in blood and urine samples under resting, basal states. The major findings of this paper are twofold. First, there is little evidence to support the hypothesis that baseline levels of the neuroendocrine markers stem from stressful life histories. Second, report of current stress (among women only) is positively correlated with higher NAL levels. Taken together, these findings question whether the neuroendocrine markers of the AL construct reflect long-term processes over the life course. Indeed, evidence here suggests that the neuroendocrine markers may reflect the exact opposite—a transient state at the time of the study.

Social relationships and allostatic load in Taiwanese elderly and near elderly

Despite the increasing evidence linking aspects of the social environment to a range of health outcomes, important questions remain concerning the precise mechanisms or pathways through which social circumstances exert their influence. Biological pathways are one important area of current research interest. Using data from the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan, we examined relationships between social environment characteristics and an index of cumulative biological dysregulation (“allostatic load,” AL) in near elderly (NE) (aged 54–70) and elderly Taiwanese (aged 71+). Longitudinal data on levels of social integration and extent of social support were used to predict cumulative AL at the final survey year. Linear regression analyses revealed that among the NE, presence of a spouse between 1996 and 2000 was associated with lower AL in 2000 among men, but not women. Among the elderly, ties with close friends and/or neighbors were found to be significantly related to lower AL for both men and women. Perceived qualities of these social relationships did not show consistent associations with AL. This relatively modest set of significant relationships stands in contrast to somewhat stronger patterns of findings from studies in Western societies. Cross-cultural differences between Western societies and an East Asian society such as Taiwan raise the intriguing possibility that contextual, normative influences on social experience affect the patterns of association between features of these social worlds and the physiological substrates of health.