A Unique Bond: Twin Bereavement and Lifespan Associations of Identical and Fraternal Twins

32 Pages Posted: 2 May 2018

See all articles by Gerard J. van den Berg

Gerard J. van den Berg

VU University Amsterdam - Department of Economics; Centre for Economic Policy Research (CEPR); IZA Institute of Labor Economics; Tinbergen Institute

Bettina Drepper

Tilburg University

Abstract

Empirical analyses of twin mortality often use models with dependent unobserved frailty terms capturing genetic and childhood environmental determinants. This ignores that mortality rates can be co-dependent due to bereavement effects, i.e. to a time-dependent causal effect of the loss of the co-twin on the mortality rate of the surviving twin. We develop a novel methodology and perform an empirical analysis based on a comprehensive model incorporating both types of dependence.We prove full identification without functional-form restrictions and we estimate models with data on twin pairs from the Danish Twin Registry. Among men, the loss of an identical co-twin at age 75 causally reduces the remaining lifetime on average by more than a year. This bereavement effect is less severe among non-identical twins or if the loss occurs at a higher age. Estimates of correlations between the frailty terms by zygosity and the ensuing implications for the relative importance of mortality determinants are highly sensitive to whether bereavement is taken into account.

Keywords: mortality, longevity, duration, frailty, genetic determinants, hazard rate, identification, loss of co-twin

JEL Classification: C41, C32, I14

Suggested Citation

van den Berg, Gerard J. and Drepper, Bettina, A Unique Bond: Twin Bereavement and Lifespan Associations of Identical and Fraternal Twins. IZA Discussion Paper No. 11448. Available at SSRN: https://ssrn.com/abstract=3170237

Gerard J. Van den Berg (Contact Author)

VU University Amsterdam - Department of Economics ( email )

De Boelelaan 1105
1081 HV Amsterdam
Netherlands
+31 20 444 6132 (Phone)
+32 20 444 6020 (Fax)

Centre for Economic Policy Research (CEPR)

London
United Kingdom

IZA Institute of Labor Economics

P.O. Box 7240
Bonn, D-53072
Germany

Tinbergen Institute

Burg. Oudlaan 50
Rotterdam, 3062 PA
Netherlands

Bettina Drepper

Tilburg University

Register to save articles to
your library

Register

Paper statistics

Downloads
13
Abstract Views
96
PlumX Metrics