Genetic determination of biological age in the Mennonites of the Midwestern United States

Successful Aging: Focus on Cognitive and Emotional Health

We review the definitions, predictors, and biobehavioral determinants of successful aging, as well as the evidence for and mechanisms of underlying selected interventions to enhance cognitive and emotional health in older adults. Defining successful aging has proven difficult, with discrepancies seen among biomedical, psychological, and lay perspectives. Although consensus is lacking, a number of studies have examined the genetic, lifestyle, and social determinants of operationalized determinants of successful aging; qualitative examinations of the meaning of the construct have also been conducted. The determinants coincide with fundamental aspects of aging. Recent clinical trials suggest that caloric restriction, physical activity, cognitive intervention, stress reduction, and social programs may enhance cognitive and emotional health in older people.

Heritability of a skeletal biomarker of biological aging

Changes in the skeletal system, which include age-related bone and joint remodeling, can potentially be used as a biomarker of biological aging. The aim of the present study was to investigate the extent and mode of inheritance of skeletal biomarker of biological aging-osseographic score (OSS), in a large sample of ethnically homogeneous pedigrees. The investigated cohort comprised 359 Chuvashian families and included 787 men aged 18-89 years (mean 46.9) and 723 women aged 18-90 years (mean 48.5). The TOSS - transformed OSS standardized in 5-year age groups for each sex, was analyzed as a BA index. We evaluated familial correlations and performed segregation analysis. Results of our study suggest the familial aggregations of TOSS variation in the Chuvashian pedigrees. In a segregation analysis we found a significant major gene (MG) effect in the individual's TOSS with a dominant most parsimonious model (H(2) = 0.32). Genetic factors (MG genotypes) explained 47% of the residual OSS variance after age adjustment and after including sex-genotype interaction, they explained 52% of the residual variance. Results of our study also indicated that the inherited difference in the skeletal aging pattern in men lies mostly in the rate of aging, but in women in the age of the onset of the period of visible skeletal changes.

Biological aging and Cox hazard analysis of mortality trends in a Mennonite community from south-central Kansas

This study investigated mortality in 568 individuals from the Goessel Mennonite community in rural central Kansas. There were three main objectives to this research: 1) characterize mortality trends within a biologically well-defined Mennonite community; 2) determine what biochemical, morphological, and physiological risk factors could be related to all-cause mortality, stratified by age and sex; and 3) compare these results to previously described variables that were associated with both biological age and mortality in this population. Mortality data were obtained from three sources: Kansas Vital Records, the Social Security death index, and church records. In total, 221 (39%) individuals were found to have died in this population between January 1980-June 2002. Analogous to the larger US population, the three leading causes of death in this community were heart disease, cancer, and stroke, accounting for 60% of all deaths. Besides advancing age, the greatest biological risk factor in this population was decreased amounts of albumin in men (relative risk, 2.47), potentially indicating underreported cases of either chronic kidney disease or frailty syndrome for males. Cox proportional hazard models demonstrated that increased amounts of total cholesterol may provide a protective effect for elderly individuals. We conclude, based on the previously described heritability of both albumin (h(2) = 0.40) and total cholesterol (h(2) = 0.50) in this population, that underlying genetic factors associated with both chronic degenerative diseases and biological aging may have important implications for understanding mortality patterns in this community.

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.

Genetic contribution to biological aging: the Framingham Study

This study assessed the contribution of genetic and nongenetic factors to biological aging in American Caucasians. The studied sample included 1402 members of 288 pedigrees from the Framingham Heart Study. The original cohort participants received hand radiography in 1967-1969 (mean age, 58.7 years) and their offspring in 1992-1993 (mean age, 51.6 years). An osseographic score was applied to hand radiographs. Standardized residuals between Osseographic Scoring System-predicted age and actual age were used as a measure of biological age (BA). In variance component genetic analysis, sex, cohort, height, body mass index, and, in women, menopausal status and estrogen use, jointly explained approximately 6% of the total variance of BA. Genetic factors explained an additional 57%. Linkage analysis of covariate-adjusted BA suggested the presence of quantitative trait loci on chromosomes 3p, 7q, 11p, 16q, and 21q. In conclusion, the variation in BA measured by radiography was strongly governed by genetic factors in a sample of American adults.