Survival analysis of longevity in siblings

Do siblings of centenarians tend to have longer life spans? To answer this question, life spans of 184 siblings for 42 centenarians have been evaluated. Two important questions have been addressed in analyzing the sibling data. First, a standard needs to be established, to which the life spans of 184 siblings are compared. In this report, an external reference population is constructed from the U.S. life tables. Its estimated mortality rates are treated as baseline hazards from which the relative mortality of the siblings are estimated. Second, the standard survival models which assume independent observations are invalid when correlation within family exists, underestimating the true variance. Methods that allow correlations are illustrated by three different methods. First, the cumulative relative excess mortality between siblings and their comparison group is calculated and used as an effective graphic tool, along with the Product Limit estimator of the survival function. The variance estimator of the cumulative relative excess mortality is adjusted for the potential within family correlation using Taylor linearization approach. Second, approaches that adjust for the inflated variance are examined. They are adjusted one-sample log-rank test using design effect originally proposed by Rao and Scott in the correlated binomial or Poisson distribution setting and the robust variance estimator derived from the log-likelihood function of a multiplicative model. Nether of these two approaches provide correlation estimate within families, but the comparison with the comparison with the standard remains valid under dependence. Last, using the frailty model concept, the multiplicative model, where the baseline hazards are known, is extended by adding a random frailty term that is based on the positive stable or the gamma distribution. Comparisons between the two frailty distributions are performed by simulation. Based on the results from various approaches, it is concluded that the siblings of centenarians had significant lower mortality rates as compared to their cohorts. The frailty models also indicate significant correlations between the life spans of the siblings. ^

Predicting Successful Aging at One Hundred Years of Age

The present study is based upon a multidimensional model of successful aging. It aims to identify subgroups of centenarians sharing communalities in successful aging profiles, and determine the role of sociodemographic factors and psychological, social, and economic resources on successful aging.

Successful aging at 100 years: the relevance of subjectivity and psychological resources

Very old individuals seem to present an admirable capacity to overcome adversities and adapt to the challenges of advanced age. However, studies focusing successful pattern of centenarians found that they may easily fail to be categorized as successful agers when objective criteria are applied. The present study examines if centenarians can be considered successful agers. Following Rowe and Kahn's successful aging model, the primary goal was to clarify whether centenarians are able to be successful agers according to objective and subjective criteria of no major disease and disability, high cognitive and physical functioning and engagement with life. The second goal was to investigate whether socio-demographic factors, psychological, social, and economic resources are related to objective and subjective successful aging profiles.

Oporto Centenarian Study

This entry presents the first population-based study conducted in Portugal, the Oporto Cente- narian Study (PT100). It starts by providing an overview of the centenarian population in Portu- gal and then describes PT100’s methodological approach (sampling, procedures, and measures) and synthesizes its main findings on three core dimensions considered to be determinants of qual- ity of life in extreme old age (Serra et al. 2011): cognitive and physical functioning, social resources (social relationships and social activi- ties), and personal attitude toward life (valuation of life). An outlook of current satellite projects of the PT100 is presented at the end.

Health Status, Living Arrangements, and Service Use at 100: Findings From the Oporto Centenarian Study

This paper describes the sociodemographic characteristics, health status, and service use of centenarians living in the community and centenarians residing in an elder care facility/nursing home and examines their main differences. Participants were 140 centenarians from the population-based Oporto Centenarian Study (Mage = 101.2; SD = 1.6). Main findings revealed that the majority of the centenarians lived at home with their family members (57.9%). Increased health care needs, living alone, and family caregiving constraints were the most common reasons for entering a nursing home. Community-dwelling centenarians were cared for mostly by their children and were less dependent and in better cognitive health than those who resided in a nursing home. Differences were found in the pattern of health service use according to the centenarians' residence, ability to pay medical expenses, and dependency level. Findings highlight the need for an accurate assessment of caregiving support systems, particularly family intergenerational duties, and of the factors constraining the access and use of health and social services. Policy makers may be guided by the insights gained from this research and work toward improvement of support options and removal of barriers to service access.