Does family size affect the mortality risk? Evidence from Swedish registers

Anna Baranowska-Rataj, Umeå University
Kieron Barclay, Stockholm University
Martin Kolk, Stockholm University

Demographic research has paid a lot of attention to the impact of childhood conditions on adult mortality. The aim of this paper is to focus on one of the key aspects of early life conditions, i.e. family size, and to examine the causal effect of growing up in a large family on mortality risk. We use high quality Swedish administrative register data. Given the concerns regarding a potentially spurious correlation between the number of siblings and mortality, we apply a quasi-experimental approach that exploits multiple births as a source of exogenous variation in the number of siblings. Previous studies have examined the effects of family size on health and mortality in a very specific context of harsh economic conditions and limited access to welfare state support, but there have been no studies of the effect of family size on mortality in modern developed societies. Our goal is to show whether growing up in a large family may be considered as a disadvantage in a country context where resources of most parents are not dramatically scarce and are complemented by a generous welfare state.