The Socio-demographic Structure of the First Wave of the TwinLife Panel Study: A Comparison with the Microcensus

Abstract

The TwinLife panel is the first longitudinal study of twin families in Germany based on a national probability sample. TwinLife has been developed to facilitate genetic sensitive research on social inequalities. The aim of this paper is to assess the usability of the TwinLife sample for such research. Therefore, first, we analyze if the social background of twins living in Germany is adequately represented in the TwinLife sample; and second, we also investigate if there are socio-demographic differences between twin and other multiplechild households in Germany which would restrict the generalizability of findings based on the TwinLife study. Specifically, we compare the distributions of key socio-demographic indicators in TwinLife with the German Microcensus using a proxy-twin and a multiplechild household sample. Our analyses show that the TwinLife sample covers the full distributions of core social inequality indicators including the lower and upper bounds, enabling researchers to use TwinLife for detailed studies of the gene-environment interplay. Furthermore, we demonstrate that (proxy-)twin and other multiple-child households in Germany are similar regarding most socio-demographic indicators. However, our analyses also indicate that participation in the first wave of the TwinLife panel was slightly selective with respect to parental education and German citizenship, especially in the younger cohorts of the study. We suggest a weighting scheme to address this selectivity.