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de Beer J.,Netherlands Interdisciplinary Demographic Institute
Demographic Research | Year: 2011

Age-specific fertility rates can be smoothed using parametric models or splines. Alternatively a relational model can be used which relates the age profile to be fitted or projected to a standard age schedule. This paper introduces TOPALS (tool for projecting age patterns using linear splines), a new relational method that is less dependent on the choice of the standard age schedule than previous methods. TOPALS models the relationship between the age-specific fertility rates to be fitted and the standard age schedule by a linear spline. This paper uses TOPALS for smoothing fertility age profiles for 30 European countries. The use of TOPALS to create scenarios of the future level and age pattern of fertility is illustrated by applying the method to project future fertility rates for six European countries. © Joop de Beer 2011.


Bijlsma M.J.,University of Groningen | Janssen F.,University of Groningen | Janssen F.,Netherlands Interdisciplinary Demographic Institute | Hak E.,University of Groningen
Pharmacoepidemiology and Drug Safety | Year: 2016

Purpose: Accurate measurement of drug adherence is essential for valid risk-benefit assessments of pharmacologic interventions. To date, measures of drug adherence have almost exclusively been applied for a fixed-time interval and without considering changes over time. However, patients with irregular dosing behaviour commonly have a different prognosis than patients with stable dosing behaviour. Methods: We propose a method, based on the proportion of days covered (PDC) method, to measure time-varying drug adherence and drug dosage using electronic records. We compare a time-fixed PDC method with the time-varying PDC method through detailed examples and through summary statistics of 100 randomly selected patients on statin therapy. Results: We demonstrate that time-varying PDC method better distinguishes an irregularly dosing patient from a stably dosing patient and demonstrate how the time-fixed method can result in a biassed estimate of drug adherence. Furthermore, the time-varying PDC method may be better used to reduce certain types of confounding and misclassification of exposure. Conclusions: The time-varying PDC method may improve longitudinal and time-to-event studies that associate adherence with a clinical outcome or (intervention) studies that seek to describe changes in adherence over time. © 2016 John Wiley & Sons, Ltd.


Merz E.-M.,Netherlands Interdisciplinary Demographic Institute
Ageing and Society | Year: 2010

This paper examines the associations between different forms of support, who provides the support and the wellbeing of older adults in Germany. Particular attention is paid to the wellbeing differences associated with kin and non-kin providers and with emotional support and instrumental support. In addition, the quality of relationships with kin and non-kin is examined as a moderator of the association between social support and wellbeing. Data for 1,146 respondents to the German Ageing Survey in 2002 were analysed to determine the combinations of emotional or instrumental support, kin or non-kin providers and relationship quality that best predicted wellbeing. Emotional support from kin and instrumental support from non-kin were both found to associate positively with wellbeing. Emotional support from non-kin providers did not associate with wellbeing, whereas instrumental support from kin providers had a negative association with one aspect of wellbeing. Higher relationship quality, whether with kin or non-kin, positively related to wellbeing. Interestingly, the negative impact of instrumental kin support was qualified by relationship quality. In other words, for people with high-quality relationships, receiving instrumental support from kin did not decrease wellbeing. When the relationship with a family carer or supporter is characterised by high quality, the challenges of frailties in old age, such as decreasing capacities and an increasing need for social support, can be met without compromising wellbeing. Copyright © 2010 Cambridge University Press.


Hershey D.A.,Oklahoma State University | Henkens K.,Netherlands Interdisciplinary Demographic Institute | Henkens K.,University of Amsterdam
Gerontologist | Year: 2014

Purpose: This study examines how life satisfaction changes as a function of the transition into retirement, distinguishing between different types of voluntary and involuntary exits. Design and Methods: Perceived satisfaction with life (SWL) was measured among 1,388 older Dutch workers on two occasions, separated by 6 years. During that time, more than half of participants (54%) left full-time employment and entered retirement. Results: Those who made a voluntarily departure from the workforce reported higher levels of perceived SWL compared with those who remained employed, whereas the life satisfaction scores of those whose departure was involuntary (due to health reasons, organizational reasons) were found to be the lowest. Other factors that had an effect on satisfaction included positive and negative health changes experienced during the 6-year interim, as well as changes in marital status due to divorce or loss of a spouse. Implications: These findings have important theoretical implications for the understanding of factors that shape individuals' perceptions of how they view the quality of their lives. From an applied perspective, the findings have implications for the development of organizational initiatives aimed at helping workers transition into retirement in such a way as to maintain high levels of subjective well-being. © 2013 The Author.


Merz E.-M.,Netherlands Interdisciplinary Demographic Institute | Jak S.,University of Amsterdam
Advances in Life Course Research | Year: 2013

This paper intends to gain insight into the role of childhood relationships and experiences within the parental home for the formation and meaning of later family relationships and loneliness. Particularly, childhood attachment to mother and father and stressful childhood experiences were studied in their association with satisfaction in the romantic relationship, the quality of adult family ties and the perceived quality of the social network, i.e. loneliness in adulthood. Based on data from the Netherlands Kinship Panel Study (N=. 3980) structural equation models were estimated to predict adult relationships and loneliness with childhood experiences. Positive attachment experiences with parents, such as reliability, closeness and supportiveness during childhood were associated with greater satisfaction in the romantic relationship, stronger family ties and less loneliness, whereas stressful childhood experiences, such as conflicts and violence negatively predicted the quality of adult relationships. Life span theoretical perspectives, such as attachment theory are discussed as useful unifying framework to study social relationships, their interconnectedness and association with outcome during all phases of life. © 2013 Elsevier Ltd.


van Ginneken J.K.,Netherlands Interdisciplinary Demographic Institute | Groenewold G.,Netherlands Interdisciplinary Demographic Institute
Open Public Health Journal | Year: 2012

Objectives: Data have been collected on self-rated health using a single question on how individuals rate their health in cross-sectional surveys carried out in a large number of countries. Doubts have been expressed about the validity of this measure and this was the main reason to undertake the current study. Study Design: Data of 21 cross-sectional surveys were analyzed derived from the World Health Survey (WHS) carried out among adults in 2002-2003. Methods: We compared the single-item self-rated health measure with a multi-item health status index. Information on both types of measures was available from WHS. The multi-item index was constructed using data on functional limitations in daily activities. Results: The relationship of age with the multi-item health status index was linear while the relationship of age with self-rated health deviated from linearity in the younger and the oldest age groups. Both measures were compared with two criterion variables: life expectancy at age 20 and self-reported chronic conditions. The multi-item index was more strongly related to life expectancy and to chronic conditions than was the single-item self-rated health measure. Conclusions: The multi-item health status index could be a stronger predictor of mortality than the single-item self-rated health measure. It is recommended to rely in health surveys as much as possible on multi-item health status measures. Single-item self-rated health measures should continue to be used in situations where there are no other alternatives available, but researchers and policy makers should be aware of their limitations. © Van Ginneken and Groenewold.


Fiori K.L.,Adelphi University | Consedine N.S.,University of Auckland | Merz E.-M.,Netherlands Interdisciplinary Demographic Institute
Research on Aging | Year: 2011

Dispositional styles of relating to significant others-adult attachment-are linked to social relatedness across the life span. Prior work has concentrated on the receipt of perceived social support and not examined links between attachment and patterns of exchange. Data from a sample of older adults (N 1,118) were used to examine how secure, dismissive, and fearfully avoidant dimensions were associated with network size and patterns of exchange in kin and non-kin networks. Security was related to larger network size, greater reciprocity, and less "giving" to kin, whereas dismissiveness was associated with smaller non-kin networks, greater reciprocity, less "giving" to kin and non-kin, and more relationships involving "receiving" from kin. Levels of fearful avoidance were associated with fewer reciprocal relationships and more "receiving" from kin. Data are interpreted in light of attachment's manifestations in motivational and interpersonal systems and may help explain variations in later life social network functioning. © The Author(s) 2011.


Kuyper L.,Rutgers Nisso Groep | Fokkema T.,Netherlands Interdisciplinary Demographic Institute
Journal of Counseling Psychology | Year: 2011

Minority stress is often cited as an explanation for greater mental health problems among lesbian, gay, and bisexual (LGB) individuals than heterosexual individuals. However, studies focusing on sex or sexual orientation differences in level of minority stress and its impact on mental health are scarce, even more so outside the United States. Performing secondary analyses on the data of a Dutch population study on sexual health, the present study examines the robustness of the minority stress model by explaining mental health problems among men and women with mostly or only same-sex sexual attraction, and men and women who are equally attracted to same-sex and opposite-sex partners in the " gay-friendly" Netherlands (N = 389; 118 gay men, 40 bisexual men, 184 lesbian women, and 54 bisexual women). Results showed that minority stress is also related to mental health of Dutch LGBs. Participants with a higher level of internalized homonegativity and those who more often encountered negative reactions from other people on their same-sex sexual attraction reported more mental health problems. Such negative reactions from others, however, had a stronger link with mental health among lesbian/gay than among bisexual participants. Openness about one's sexual orientation was related to better mental health among sexual minority women, but not among their male counterparts. Suggestions for future research, implications for counseling, and other societal interventions are discussed. © 2011 American Psychological Association.


Damman M.,Netherlands Interdisciplinary Demographic Institute | Henkens K.,Netherlands Interdisciplinary Demographic Institute | Henkens K.,University of Tilburg | Kalmijn M.,University of Tilburg
Journals of Gerontology - Series B Psychological Sciences and Social Sciences | Year: 2011

Objectives. In empirical studies on predictors of retirement, midlife experiences have often remained implicit or been neglected. This study aims to improve our understanding of retirement by examining the impact of midlife educational, work, health, and family experiences on early retirement intentions and behavior. We distinguish theoretically and empirically between financial and nonfinancial preretirement factors through which midlife experiences could affect retirement. Methods. Using panel data of 1,229 Dutch male older workers, we estimated linear regression models to explain retirement intentions and logistic regression models to explain retirement behavior. Results. Midlife experiences in all studied life spheres are related to retirement intentions. Educational investments, job changes, late transitions into parenthood, and late divorces are associated with weaker intentions to retire early. Midlife health problems are related to stronger early retirement intentions. For midlife work and family experiences, the relationships are (partly) mediated by the preretirement financial opportunity structure. In the educational, work, and health spheres, the preretirement nonfinancial situation has a mediating effect. Only some of the predictors of retirement intentions also predicted retirement behavior. © The Author 2011.


Heij C.,Erasmus University Rotterdam | Bijwaard G.E.,Netherlands Interdisciplinary Demographic Institute | Knapp S.,Erasmus University Rotterdam
Transportation Research Part D: Transport and Environment | Year: 2011

Global trade largely depends on maritime transport, and appropriate ships are needed to protect cargo but to minimize environmental damage and to this end, flag and port state authorities expend considerable effort in ship safety inspections. This paper investigates the safety gains of current inspection rules as well as options for further developments. The analysis is based on a dataset of over 400,000 ship arrivals covering 2002-2007, and is complemented with data on port state control and industry inspections and casualties. The results indicate considerable potential for safety gains from incorporating casualty risks more explicitly in port state control strategies to select ships for safety inspections. © 2010 Elsevier Ltd.

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