Browsing by Author "Vaupel, JW"
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Item Open Access A life-history evaluation of the impact of maternal effects on recruitment and fisheries reference points(Canadian Journal of Fisheries and Aquatic Sciences, 2014-01-01) Calduch-Verdiell, N; MacKenzie, BR; Vaupel, JW; Andersen, KHFishing causes dramatic changes in the age and size structure of fish stocks. In particular, the targeting of the largest and oldest individuals in a stock changes the age and size distribution of that stock. A large female produces a higher quantity of eggs than a young female because of its larger size, but recent laboratory evidence further indicates that large females also produce eggs of higher quality, a phenomenon known as maternal effects. However, most traditional management models assume that all female fish contribute equally per unit biomass to future recruitment. Here we investigate whether this assumption is valid by calculating the impact of maternal effects both before and after accounting for density-dependent effects. We find that the contribution of large individuals to reproduction is much more pronounced for unfished than for fished stocks. Fisheries reference points are largely unaffected by maternal effects. Our results indicate that the incorporation of maternal effects into impact assessments of fisheries is not expected to change advice substantially. Important exceptions are stocks whose demography is very vulnerable to fishing (and which therefore have low fishing reference points) for which maternal effects are relevant and necessary to consider. © 2014 Published by NRC Research Press.Item Open Access Attrition in heterogeneous cohorts(Demographic Research, 2010-11-10) Vaupel, JW; Zhang, ZIn a heterogeneous cohort, the change with age in the force of mortality or some other kind of hazard or intensity of attrition depends on how the hazard changes with age for the individuals in the cohort and on how the composition of the cohort changes due to the loss of those most vulnerable to attrition. Here we prove that the change with age for the cohort equals the average of the change in the hazard for the individuals in the cohort minus the variance in the hazard across individuals. The variance captures the compositional change. This very general and remarkably elegant relationship can be applied to understand and to analyze changes with age in many kinds of demographic hazards, including, e.g., the lifetable aging rate or the intensity of first births. © 2010 James W. Vaupel & Zhen Zhang.Item Open Access Demographic characteristics of sardinian centenarian genealogies: Preliminary results of the AKeA2 study(Demographic Research, 2015-01-01) Lipsi, RM; Caselli, G; Pozzi, L; Baggio, G; Carru, C; Franceschi, C; Vaupel, JW; Deiana, L© 2015 Rosa Maria Lipsi et al.Objective: This article provides an overview of the AKeA2 study, with a particular focus on data collection concerning family genealogies of the Sardinian centenarians and controls, and on the quality of these data. A first analysis of the main characteristics of the survey data is also summarized and selected preliminary results are presented. Methods: We use descriptive statistics to analyze data collected by the AKeA2 survey on Sardinian centenarians and controls. Results: Centenarian women have on average fewer children, and at an older age, particularly for their last child. The mothers of centenarians, especially centenarian women, lived longer on average than those of deceased controls and controls born between 1905 and 1910 but still living at the moment of the survey.Item Open Access Design, recruitment, logistics, and data management of the GEHA (Genetics of Healthy Ageing) project.(Exp Gerontol, 2011-11) Skytthe, A; Valensin, S; Jeune, B; Cevenini, E; Balard, F; Beekman, M; Bezrukov, V; Blanche, H; Bolund, L; Broczek, K; Carru, C; Christensen, K; Christiansen, L; Collerton, JC; Cotichini, R; de Craen, AJM; Dato, S; Davies, K; De Benedictis, G; Deiana, L; Flachsbart, F; Gampe, J; Gilbault, C; Gonos, ES; Haimes, E; Hervonen, A; Hurme, MA; Janiszewska, D; Jylhä, M; Kirkwood, TBL; Kristensen, P; Laiho, P; Leon, A; Marchisio, A; Masciulli, R; Nebel, A; Passarino, G; Pelicci, G; Peltonen, L; Perola, M; Poulain, M; Rea, IM; Remacle, J; Robine, JM; Schreiber, S; Scurti, M; Sevini, F; Sikora, E; Skouteri, A; Slagboom, PE; Spazzafumo, L; Stazi, MA; Toccaceli, V; Toussaint, O; Törnwall, O; Vaupel, JW; Voutetakis, K; Franceschi, C; GEHA consortiumIn 2004, the integrated European project GEHA (Genetics of Healthy Ageing) was initiated with the aim of identifying genes involved in healthy ageing and longevity. The first step in the project was the recruitment of more than 2500 pairs of siblings aged 90 years or more together with one younger control person from 15 areas in 11 European countries through a coordinated and standardised effort. A biological sample, preferably a blood sample, was collected from each participant, and basic physical and cognitive measures were obtained together with information about health, life style, and family composition. From 2004 to 2008 a total of 2535 families comprising 5319 nonagenarian siblings were identified and included in the project. In addition, 2548 younger control persons aged 50-75 years were recruited. A total of 2249 complete trios with blood samples from at least two old siblings and the younger control were formed and are available for genetic analyses (e.g. linkage studies and genome-wide association studies). Mortality follow-up improves the possibility of identifying families with the most extreme longevity phenotypes. With a mean follow-up time of 3.7 years the number of families with all participating siblings aged 95 years or more has increased by a factor of 5 to 750 families compared to when interviews were conducted. Thus, the GEHA project represents a unique source in the search for genes related to healthy ageing and longevity.Item Open Access Effects of FOXO genotypes on longevity: a biodemographic analysis.(J Gerontol A Biol Sci Med Sci, 2010-12) Zeng, Y; Cheng, L; Chen, H; Cao, H; Hauser, ER; Liu, Y; Xiao, Z; Tan, Q; Tian, XL; Vaupel, JWBased on data from 760 centenarians and 1060 middle-age controls (all Han Chinese), this article contributes biodemographic insights and syntheses concerning the magnitude of effects of the FOXO genotypes on longevity. We also estimate independent and joint effects of the genotypes of FOXO1A and FOXO3A genes on long-term survival, considering carrying or not-carrying the minor allele of the single-nucleotide polymorphism of another relevant gene. We found substantial gender differences in the independent effects; positive effects of FOXO3A and negative effects of FOXO1A largely compensate each other if one carries both, although FOXO3A has a stronger impact. Ten-year follow-up cohort analysis shows that at very advanced ages 92-110, adjusted for various confounders, positive effects of FOXO3A on survival remain statistically significant, but no significant effects of FOXO1A alone; G × G interactions between FOXO1A-209 and FOXO3A-310 or FOXO3A-292 decrease survival likelihood by 32%-36% (p < .05); G × E interactions between FOXO1A-209 and regular exercise increase survival likelihood by 31%-32% (p < .05).Item Open Access Forecasting life expectancy in an international context(International Journal of Forecasting, 2012-04-01) Torri, T; Vaupel, JWOver the past two centuries, the life expectancy has more than doubled in many countries, for both males and females. The levels of the countries with the highest life expectancies have risen almost linearly. We exploit this regularity by using the classic univariate ARIMA model to forecast future levels of best-practice life expectancy. We then compare two alternative stochastic models for forecasting the gap between the best-practice level and life expectancy in a particular population. One of our approaches is based on the concept of discrete geometric Brownian motion; our other approach relies on a discrete model of geometric mean-reverting processes. A key advantage of our strategy is that the life expectancies forecast for different countries are positively correlated because of their tie to the forecast best-practice line. We provide illustrations based on Italian and US data. © 2011 International Institute of Forecasters.Item Open Access GxE interactions between FOXO genotypes and drinking tea are significantly associated with prevention of cognitive decline in advanced age in China.(J Gerontol A Biol Sci Med Sci, 2015-04) Zeng, Y; Chen, H; Ni, T; Ruan, R; Feng, L; Nie, C; Cheng, L; Li, Y; Tao, W; Gu, J; Land, KC; Yashin, A; Tan, Q; Yang, Z; Bolund, L; Yang, H; Hauser, E; Willcox, DC; Willcox, BJ; Tian, X; Vaupel, JWLogistic regression analysis based on data from 822 Han Chinese oldest old aged 92+ demonstrated that interactions between carrying FOXO1A-266 or FOXO3-310 or FOXO3-292 and tea drinking at around age 60 or at present time were significantly associated with lower risk of cognitive disability at advanced ages. Associations between tea drinking and reduced cognitive disability were much stronger among carriers of the genotypes of FOXO1A-266 or FOXO3-310 or FOXO3-292 compared with noncarriers, and it was reconfirmed by analysis of three-way interactions across FOXO genotypes, tea drinking at around age 60, and at present time. Based on prior findings from animal and human cell models, we postulate that intake of tea compounds may activate FOXO gene expression, which in turn may positively affect cognitive function in the oldest old population. Our empirical findings imply that the health benefits of particular nutritional interventions, including tea drinking, may, in part, depend upon individual genetic profiles.Item Open Access Interaction Between the FOXO1A-209 Genotype and Tea Drinking Is Significantly Associated with Reduced Mortality at Advanced Ages.(Rejuvenation Res, 2016-06) Zeng, Y; Chen, H; Ni, T; Ruan, R; Nie, C; Liu, X; Feng, L; Zhang, F; Lu, J; Li, J; Li, Y; Tao, W; Gregory, SG; Gottschalk, W; Lutz, MW; Land, KC; Yashin, A; Tan, Q; Yang, Z; Bolund, L; Ming, Q; Yang, H; Min, J; Willcox, DC; Willcox, BJ; Gu, J; Hauser, E; Tian, X; Vaupel, JWOn the basis of the genotypic/phenotypic data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) and Cox proportional hazard model, the present study demonstrates that interactions between carrying FOXO1A-209 genotypes and tea drinking are significantly associated with lower risk of mortality at advanced ages. Such a significant association is replicated in two independent Han Chinese CLHLS cohorts (p = 0.028-0.048 in the discovery and replication cohorts, and p = 0.003-0.016 in the combined dataset). We found the associations between tea drinking and reduced mortality are much stronger among carriers of the FOXO1A-209 genotype compared to non-carriers, and drinking tea is associated with a reversal of the negative effects of carrying FOXO1A-209 minor alleles, that is, from a substantially increased mortality risk to substantially reduced mortality risk at advanced ages. The impacts are considerably stronger among those who carry two copies of the FOXO1A minor allele than those who carry one copy. On the basis of previously reported experiments on human cell models concerning FOXO1A-by-tea-compounds interactions, we speculate that results in the present study indicate that tea drinking may inhibit FOXO1A-209 gene expression and its biological functions, which reduces the negative impacts of FOXO1A-209 gene on longevity (as reported in the literature) and offers protection against mortality risk at oldest-old ages. Our empirical findings imply that the health outcomes of particular nutritional interventions, including tea drinking, may, in part, depend upon individual genetic profiles, and the research on the effects of nutrigenomics interactions could potentially be useful for rejuvenation therapies in the clinic or associated healthy aging intervention programs.Item Open Access Maternal longevity is associated with lower infant mortality(Demographic Research, 2014-01-01) Caselli, G; Lapucci, E; Lipsi, RM; Pozzi, L; Baggio, G; Carru, C; Deiana, L; Franceschi, C; Vaupel, JW© 2014 Caselli et al.Objective: Referring to the multidisciplinary and multipurpose survey AKeA2, and focusing on family genealogy data on centenarian women and controls, this paper aims to verify the hypothesis that maternal longevity is associated with lower infant mortality in offspring, after having controlled for fertility characteristics, familial longevity and some contextual variables. Methods: The association between the longevity of a mother and her children's infant mortality level was assessed using a multivariate Poisson Regression Model with robust estimates, which is suitable for estimating consistently and efficiently the relative risk when binary data are used. Results: Our results show an association between longevity and infant mortality among the children of the Sardinians who survived to become centenarians. Infant mortality is significantly lower for children belonging to a mother born and living in Sassari and Oristano than Nuoro, close to each other and both located on the Western coast.Item Open Access Mortality implications of mortality plateaus(SIAM Review, 2015-01-01) Missov, TI; Vaupel, JWThis article aims to describe in a unified framework all plateau-generating random effects models in terms of (i) plausible distributions for the hazard (baseline mortality) and the random effect (unobserved heterogeneity, frailty) as well as (ii) the impact of frailty on the baseline hazard. Mortality plateaus result from multiplicative (proportional) and additive hazards, but not from accelerated failure time models. Frailty can have any distribution with regularly-varying-at-0 density and the distribution of frailty among survivors to each subsequent age converges to a gamma distribution. In a multiplicative setting the baseline cumulative hazard can be represented as the inverse of the negative logarithm of any completely monotone function. If the plateau is reached, the only meaningful solution at the plateau is provided by the gamma-Gompertz model.Item Open Access Senescence vs. sustenance: Evolutionary-demographic models of aging(Demographic Research, 2010-11-10) Baudisch, A; Vaupel, JWHumans, and many other species, suffer senescence: mortality increases and fertility decreases with adult age. Some species, however, enjoy sustenance: mortality and fertility remain constant. Here we develop simple but general evolutionary-demographic models to explain the conditions that favor senescence vs. sustenance. The models illustrate how mathematical demography can deepen understanding of the evolution of aging. © 2010 Annette Baudisch & James W. Vaupel.Item Open Access Sex differences in health and mortality in Moscow and Denmark.(Eur J Epidemiol, 2014-04) Oksuzyan, A; Shkolnikova, M; Vaupel, JW; Christensen, K; Shkolnikov, VMIn high income countries females outlive men, although they generally report worse health, the so-called male-female health-survival paradox. Russia has one of the world's largest sex difference in life expectancy with a male disadvantage of more than 10 years. We compare components of the paradox between Denmark and Moscow by examining sex differences in mortality and several health measures. The Human Mortality Database and the Russian Fertility and Mortality Database were used to examine sex differences in all-cause death rates in Denmark, Russia, and Moscow in 2007-2008. Self-reported health data were obtained from the Study of Middle-Aged Danish Twins (n = 4,314), the Longitudinal Study of Aging Danish Twins (n = 4,731), and the study of Stress, Aging, and Health in Russia (n = 1,800). In both Moscow and Denmark there was a consistent female advantage at ages 55-89 years in survival and a male advantage in self-rated health, physical functioning, and depression symptomatology. Only on cognitive tests males performed similarly to or worse than women. Nevertheless, Muscovite males had more than twice higher mortality at ages 55-69 years compared to Muscovite women, almost double the ratio in Denmark. The present study showed that despite similar directions of sex differences in health and mortality in Moscow and Denmark, the male-female health-survival paradox is very pronounced in Moscow suggesting a stronger sex-specific disconnect between health indicators and mortality among middle-aged and young-old Muscovites.Item Open Access The compadre Plant Matrix Database: An open online repository for plant demography(Journal of Ecology, 2015-01-01) Salguero-Gómez, R; Jones, OR; Archer, CR; Buckley, YM; Che-Castaldo, J; Caswell, H; Hodgson, D; Scheuerlein, A; Conde, DA; Brinks, E; de Buhr, H; Farack, C; Gottschalk, F; Hartmann, A; Henning, A; Hoppe, G; Römer, G; Runge, J; Ruoff, T; Wille, J; Zeh, S; Davison, R; Vieregg, D; Baudisch, A; Altwegg, R; Colchero, F; Dong, M; de Kroon, H; Lebreton, JD; Metcalf, CJE; Neel, MM; Parker, IM; Takada, T; Valverde, T; Vélez-Espino, LA; Wardle, GM; Franco, M; Vaupel, JW© 2014 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.Summary: Schedules of survival, growth and reproduction are key life-history traits. Data on how these traits vary among species and populations are fundamental to our understanding of the ecological conditions that have shaped plant evolution. Because these demographic schedules determine population growth or decline, such data help us understand how different biomes shape plant ecology, how plant populations and communities respond to global change and how to develop successful management tools for endangered or invasive species. Matrix population models summarize the life cycle components of survival, growth and reproduction, while explicitly acknowledging heterogeneity among classes of individuals in the population. Matrix models have comparable structures, and their emergent measures of population dynamics, such as population growth rate or mean life expectancy, have direct biological interpretations, facilitating comparisons among populations and species. Thousands of plant matrix population models have been parameterized from empirical data, but they are largely dispersed through peer-reviewed and grey literature, and thus remain inaccessible for synthetic analysis. Here, we introduce the compadre Plant Matrix Database version 3.0, an open-source online repository containing 468 studies from 598 species world-wide (672 species hits, when accounting for species studied in more than one source), with a total of 5621 matrices. compadre also contains relevant ancillary information (e.g. ecoregion, growth form, taxonomy, phylogeny) that facilitates interpretation of the numerous demographic metrics that can be derived from the matrices. Synthesis. Large collections of data allow broad questions to be addressed at the global scale, for example, in genetics (genbank), functional plant ecology (try, bien, d3) and grassland community ecology (nutnet). Here, we present compadre, a similarly data-rich and ecologically relevant resource for plant demography. Open access to this information, its frequent updates and its integration with other online resources will allow researchers to address timely and important ecological and evolutionary questions. Synthesis: Large collections of data sets allow broad questions to be addressed at the global scale, for example, in genetics (genbank), functional plant ecology (try, bien, d3) and grassland community ecology (nutnet). Here, we present compadre, a similarly data-rich and ecologically relevant resource for plant demography. Open access to this information, its frequent updates and its integration with other online resources will allow researchers to address timely and important ecological and evolutionary questions.Item Open Access The difference between alternative averages(Demographic Research, 2012-12-06) Vaupel, JW; Zhang, ZBackground: Demographers have long been interested in how compositional change, e.g., change in age structure, affects population averages. Objective: We want to deepen understanding of how compositional change affects population averages. Results: The difference between two averages of a variable, calculated using alternative weighting functions, equals the covariance between the variable and the ratio of the weighting functions, divided by the average of the ratio. We compare weighted and unweighted averages and also provide examples of use of the relationship in analyses of fertility and mortality. Comments: Other uses of covariances in formal demography are worth exploring. © 2012 James W. Vaupel & Zhen Zhang.Item Open Access Unobserved population heterogeneity(Demographic Research, 2014-09) Vaupel, JW; Yashin, AIItem Open Access Unobserved population heterogeneity: A review of formal relationships(Demographic Research, 2014-01-01) Vaupel, JW; Missov, TI© 2014 James W. Vaupel & Trifon I. Missov.Background: Survival models accounting for unobserved heterogeneity (frailty models) play an important role in mortality research, yet there is no article that concisely summarizes useful relationships. Objective: We present a list of important mathematical relationships that govern populations in which individuals differ from each other in unobserved ways. For some relationships we present proofs that, albeit formal, tend to be simple and intuitive. Methods: We organize the article in a progression, starting with general relationships and then turning to models with stronger and stronger assumptions. Results: We start with the general case, in which we do not assume any structure of the underlying baseline hazard, the frailty distribution, or their link to one another. Then we sequentially assume, first, a relative-risk model; second, a gamma distribution for frailty; and, finally, a Gompertz and Gompertz-Makeham specification for baseline mortality. Comments: The article might serve as a handy overall reference to frailty models, especially for mortality research.