The feasibility of predicting longevity in the elderly: conceptual and empirical aspects

The present dissertation is a report of a search process to find out if the level of variance explained typically reported in longevity studies can be increased. Two premises form the rationale of this endeavor: 1. the methods used in most studies of longevity may be improved-upon; 2. the data used to predict longevity in most studies may not be the most appropriate with regard to the target population: those persons indicated as "elderly". In the course of this search process, several new concepts and empirical approaches will prove to be useful. If the search process has a positive outcome, it will offer guidelines to investigators planning longevity studies in the near future. If its outcome turns out to be negative, the lack of predictive ability of longevity studies may be a basic fact which can no longer be ignored and which has consequences for our thinking about and interpretation of predictors of longevity. This dissertation, in other words, deals with the feasibility of predicting longevity in the elderly, from a concern with both the scientific value and the practical applicability of findings. In terms of the typology described above, the research constituting the search process follows the approach of the second category: basically descriptive studies that attempt to identify groups at risk

The Role of Early-Life Conditions in the Cognitive Decline due to Adverse Events Later in Life

Cognitive functioning of elderly individuals may be affected by events such as the loss of a (grand)child or partner or the onset of a serious chronic condition, and by negative economic shocks such as job loss or the reduction of pension benefits. It is conceivable that the impact of such events is stronger if conditions early in life were adverse. In this paper we address this using a Dutch longitudinal database that follows elderly individuals for more than 15 years and contains information on demographics, socio-economic conditions, life events, health, and cognitive functioning. We exploit exogenous variation in early-life conditions as generated by the business cycle. We also examine to what extent the cumulative effect of consecutive shocks later in life exceeds the sum of the separate effects, and whether economic and health shocks later in life reinforce each other in their effect on cognitive functioning.cognitive functioning, business cycle, bereavement, developmental origins, retirement, health, long-run effects, dementia

Changes in admission to long-term care institutions in the Netherlands: comparing two cohorts over the period 1996–1999 and 2006–2009

Using data from two cohorts, we examine to what extent a decline in institutional care in the Netherlands is associated with changes in the need for care and/or societal factors. We compared older adults, aged 65–89, who were admitted to a long-term care (LTC) institution in the period 1996–1999 and 2006–2009. Using the Andersen model, we tested per block of predisposing, enabling and need factors, which factors were significant predictors of admission to institutional care. With a Blinder–Oaxaca decomposition regression, we decomposed the difference in admission to an LTC institution between the period 1996–1999 and 2006–2009 into a part that is due to differences in health needs and other factors such as effect of policy, social values, and technology. Between 1996 and 2006, the percentage of co-residing partners and income increased and the average level of loneliness decreased significantly. The prevalence of disability, chronic diseases, however, increased. Whereas the care by partners declined, the formal care by professionals increased. Although the observed decline in the admission rate to institutional care was relatively small across the 10 years (from5.3 %in 1996–1999 to 4.5 % in 2006–2009, a 15 % decrease), the probability of admission in 2006–2009 was relatively much lower when accounting for changes in the health and social conditions of the participants: the probability was 1.7–2.1 % point lower for adults in the period 2006–2009 compared to 1996–1999, a 32–40 % decrease. Our results show that the decline in the admission rate to LTC institutions is not the result of changes in need. The decline is suggested to be the combined effect of changes in policy, technological advances and changes in social norms

Occupation-Based Life Expectancy:Actuarial Fairness in Determining Statutory Retirement Age

This study examines occupation-based differences in life expectancy and the extent to which health accounts for these differences. Twentyseven-year survival follow-up data were used from the Dutch population-based Longitudinal Aging Study Amsterdam (n = 2,531), initial ages 55–85 years. Occupation was based on longest-held job. Results show that the non-skilled general, technical and transport domains had an up to 3.5-year shorter life expectancy than the academic professions, accounting for the compositional characteristics age and gender. Statutory retirement age could be made to vary accordingly, by allowing a proportionally greater pension build-up in the shorter-lived domains. Health accounted for a substantial portion of the longevity difference, ranging from 20 to 66%, depending on the health indicator. Thus, health differences between occupational domains today can be used as a means to tailor retirement ages to individuals’ risks of longevity. These data provide a proof of principle for the development of an actuarially fair method to determine statutory retirement ages

Who live longer than their age peers : individual predictors of longevity among older individuals

BACKGROUND: There are a very few studies focusing on the individual-based survival with a long follow-up time. AIM: To identify predictors and determine their joint predictive value for longevity using individual-based outcome measures. METHODS: Data were drawn from Tampere Longitudinal Study on Aging (TamELSA), a study of individuals' age 60-89 years (N = 1450) with a mortality follow-up of up to 35 years. Two measures of longevity were used: the longevity difference (LD) and realized probability of dying (RPD), both of which compare each individual's longevity with their life expectancy as derived from population life tables. Independent variables were categorized into five domains: sociodemographic, health and functioning, subjective experiences, social activities, and living conditions. Linear regression models were used in three steps: bivariate analysis for each variable, multivariate analysis based on backward elimination for each domain, and one final model. RESULTS: The most important predictors of both outcomes were marital status, years smoked regularly, mobility, self-rated health, endocrine and metabolic diseases, respiratory diseases, and unwillingness to do things or lack of energy. The explained variance in longevity was 13.8% for LD and 14.1% for RPD. This demonstrated a large proportion of unexplained error margins for the prediction of individual longevity, even though many known predictors were used. DISCUSSION AND CONCLUSIONS: Several predictors associated with longer life were found. Yet, on an individual level, it remains difficult to predict who will live longer than their age peers. The stochastic element in the process of aging and in death may affect this prediction.publishedVersionPeer reviewe