Parity and Mortality: An Examination of Different Explanatory Mechanisms Using Data on Biological and Adoptive Parents

Kieron Barclay,Martin Kolk

doi:10.1007/s10680-018-9469-1

Abstract

A growing literature has demonstrated a relationship between parity and mortality, but the explanation for that relationship remains unclear. This study aims to pick apart physiological and social explanations for the parity–mortality relationship by examining the mortality of parents who adopt children, but who have no biological children, in comparison with the mortality of parents with biological children. Using Swedish register data, we study post-reproductive mortality amongst women and men from cohorts born between 1915 and 1960, over ages 45–97. Our results show the relative risks of mortality for adoptive parents are always lower than those of parents with biological children. Mortality amongst adoptive parents is lower for those who adopt more than one child, while for parents with biological children we observe a U-shaped relationship, where parity-two parents have the lowest mortality. Our discussion considers the relative importance of physiological and social depletion effects, and selection processes.

Highlights

This study contributes to the literature concerning the relationship between parity and mortality by examining the mortality of women and men who adopt children in contemporary Sweden
We argue that since theories based on the physiological drain of childbearing concerning the hypothesised parity–mortality relationship do not apply to adoptive parents, we will be able to look at the relative contribution of the posited social mechanisms relating parity to post-reproductive mortality
After adjusting for SES and educational attainment, the estimates for adoptive mothers do not vary a great deal, indicating that these types of parents were already a select group in terms of socioeconomic status and related lifestyle factors thanks to the vetting procedure conducted by the adoption authorities in Sweden

Summary

Introduction

This study contributes to the literature concerning the relationship between parity and mortality by examining the mortality of women and men who adopt children in contemporary Sweden. Recent meta-analyses of studies using contemporary data on the relationship between biological parity and all-cause mortality show that there is a J-shaped relationship between the two variables (Hognas et al 2017; Zeng et al 2016); mortality is elevated for childless men and women, is lowest for parity-two mothers and fathers, and increases relative to parity-two parents at higher parities (Kvale et al 1994; Doblhammer 2000; Manor et al 2000; Hurt et al 2004; Grundy and Tomassini 2005; Koski-Rahikalla et al 2006; Grundy 2009; Jaffe et al 2009, Dior et al 2013). In contemporary populations in high-income societies the relationship between parity and mortality is generally similar for both sexes (Grundy and Kravdal 2008, 2010; Barclay et al 2016)

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