Quantitative genetic analysis of biobehavioral markers of aging in Swedish studies of adult twins

Perinatal complications, lipid peroxidation, and mental health problems in a large community pediatric sample

Replicated evidence indicates that perinatal complications are associated with increased markers of oxidative stress and with mental health problems in children. However, there are fewer reports on the impact of perinatal complications in later phases of development. We aimed to investigate the estimated effects of perinatal complications on levels of lipid peroxidation and on psychopathology in children and adolescents. The study is part of the High Risk Cohort Study for Psychiatric Disorders; the population was composed by 554 students, 6-14 years of age. Serum levels of malondialdehyde, a product of lipid peroxidation, were measured by the TBARS method. A household interview with parents and caregivers was conducted and included inquiries about perinatal history, the Child Behavior Checklist (CBCL), and parent's evaluation, using the Mini International Psychiatric Interview (MINI). We created a cumulative risk index, conceptualized as each individual's cumulative exposure to perinatal complications. Results indicate that perinatal complications were associated with higher levels of TBARS. After adjusting for age, gender, socio-economic status, CBCL total problems score, parental psychopathology, and childhood maltreatment, children exposed to 3 or more perinatal complications had an 26.9% (95% CI 9.9%, 46.6%) increase in TBARS levels, relative to the unexposed group. Exploratory mediation analysis indicated that TBARS levels partially mediated the association between perinatal complications and externalizing problems. In conclusion, an adverse intrauterine and/or early life environment, as proxied by the cumulative exposure to perinatal complications, was independently associated with higher levels of lipid peroxidation in children and adolescents.

Genes, Environment, and Time: The Vietnam Era Twin Study of Aging (VETSA)

The Vietnam Era Twin Study of Aging (VETSA) is a large-scale investigation of cognitive aging from middle to later age. The intended sample of 1440 twin subjects is recruited from the Vietnam Era Twin Registry (VETR), a registry of middle-aged male-male twin pairs who both served in the military during the Vietnam conflict (1965–1975). VETSA employs a multitrait multimethod approach to cognitive assessment to focus on the genetic and environmental contributions to cognitive processes over time, as well as the relative contributions to cognitive aging from health, social, personality, and other contextual factors. The cognitive domains of episodic memory, working memory, abstract reasoning, and inhibitory executive functioning are assessed through neuropsychological testing. In addition, VETSA obtains the participant's score on the Armed Forces Qualification Test, taken at the time of induction into the military around age 20 years, and readministers the test. Two other projects — VETSA Cortisol and VETSA Magnetic Resonance Imaging — are also in progress using subsamples of the VETSA twins. Prior waves of data collection by VETSA investigators using the VETR have provided historical data on physical and mental health, while future waves of VETSA data collection are planned every 5 years. These methods will provide data on multiple pheno-types in the same individuals with regard to genetic and environmental contributions to cognitive functioning over time, personality and interpersonal risk and protective factors, stress and cortisol regulation, and structural brain correlates of aging processes.

Genetic influences on cognitive functions in the elderly: a selective review of twin studies

In this review, we examined the published reports on the heritability of cognitive functioning in old age. Twenty-four papers from five study centers, comprising of participants with a mean age of 65 years and above were examined. The comparability of findings from different studies was compromised by the use of different measures for the same cognitive domain, and with large scale twin studies in cognitive aging limited to a few Scandinavian countries. While the results from cross-sectional samples appear to lend support for the notion that heritability of cognitive functions decreases in the elderly, the findings are best considered inconclusive. Longitudinal reports show little evidence for genetic effects, but an increase in unique environmental influences on the rate of cognitive change as age increases. In relation to the two prominent theories of cognitive aging, the genetic influence on processing speed as a major contributor to cognitive aging has been indicated in three reports, whereas the genetic relationship between executive functions and other cognitive functions has not been explored. Only two studies have focused on sex difference and did not find sex-specific genetic influence in cognitive abilities. This review indicates that there are complex relationships between heritability, environmental influence, and cognitive functions in the elderly. It highlights the need for more research, with consistent and appropriate cognitive measures, with data obtained from larger and more geographically and culturally diverse twin samples.

Genetic influence on contrast sensitivity in middle-aged male twins

Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5-18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14-38%), whereas individual-specific environmental influences accounted for 62-86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age.

Disentangling the genetic determinants of human aging: biological age as an alternative to the use of survival measures

The choice of a phenotype is critical for the study of a complex genetically regulated process, such as aging. To date, most of the twin and family studies have focused on broad survival measures, primarily age at death or exceptional longevity. However, on the basis of recent studies of twins and families, biological age has also been shown to have a strong genetic component, with heritability estimates ranging from 27% to 57%. The aim of this review is twofold: first, to summarize growing consensus on reliable methods of biological age assessment, and second, to demonstrate validity of this phenotype for research in the genetics of aging in humans.

Cross-sectional age differences in personality among medicare patients aged 65 to 100

1,084 older Medicare recipients were orally administered the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa & R. R. McCrae, 1992). Participants were assigned to groups based on gender and age (65-79 or 80-100). An analysis of covariance showed that women had significantly higher Neuroticism, Openness, and Agreeableness scores; that older participants were significantly higher in Agreeableness; and that age differences in Agreeableness were significantly greater in men than in women. With the exception of Agreeableness, this study provides no evidence for age differences among those in the last decades of life.

Health related quality of life in pregeriatric patients with chronic diseases at urban, public supported clinics

BACKGROUND

Understanding health-related quality of life (HRQOL) leads to more effective and focused healthcare. America's growing health disparities makes it is increasingly necessary to understand the HRQOL of pregeriatric individuals who are now 55-64 years old, i.e. before they are eligible for federally mandated health care at age 65. Our study measured the self-perceived HRQOL of pregeriatric, poor patients with multiple chronic diseases treated at 2 public clinics.

METHODS

Consecutive patients aged 55-64 years, many with multiple chronic diseases, responded in an interview to the 36-Item Short-Form Health Survey (SF-36) as a general measure of HRQOL during a regular visit to one of two university-staffed urban public clinics.

RESULTS

The perceived physical and mental functioning of 316 pregeriatric patients was tabulated from SF-36 scores to yield their HRQOL. Their scores were statistically significantly lower than those of the general US pregeriatric population and lower than averages for US patients with multiple chronic diseases. All eight subscale scores of SF-36 were 16% to 36% lower compared with the averages of the general US pregeriatric population. Further, as the number of chronic diseases increased, the lower was the HRQOL. Lower physical and mental scores were associated with a lower income, unemployment, and higher numbers of multiple chronic diseases.

CONCLUSION

Chronic diseases have a powerful negative impact on perceived mental and physical functioning in pregeriatric patients. HRQOL information can assist health care providers to gain a more complete picture of their pregeriatric patients' health.