The Effects of Extrinsic Mortality during Early Childhood on Individuals’ Reproductive Outcomes: A Case Study on 18th and 19th century Krummhörn, Germany

Katharina E. Pink, Family and Population Studies, Centre for Sociological Research, Faculty of Social Sciences, KU Leuven
Paul Puschmann, Family and Population Studies, Centre for Sociological Research, Faculty of Social Sciences, KU Leuven
Kai P. Willführ, Department of Educational- and Social Sciences, Carl von Ossietzky University of Oldenburg
Eckart Voland, Department of Biophilosophy, Justus Liebig University Gießen

Life history theory predicts that individuals adapt their life trajectories to the local ecology. One important ecological factor that influences the timing of certain life events is extrinsic mortality. Extrinsic mortality is a result of environmental hazards such as infectious diseases, predation, war, famine or accidents which is an age-specific risk that is not under the individual’s control. Previous studies in preindustrial and contemporary societies have shown that exposure to high extrinsic mortality during early childhood (0-7 years) can fasten individuals’ life history strategies characterized by earlier age of menarche, first pregnancy and birth. The present study investigates the impact of high extrinsic mortality during early childhood on the age at first marriage, age at first birth, out of wedlock fertility, and the length of birth intervals. Extrinsic mortality is measured in two ways: (1) mortality on district level, and (2) mortality on family level. On the district level we utilize crude death rates, and on the family level we study the effect of mother’s death, father’s death and siblings’ death. We predict that individuals who were exposed to high extrinsic mortality during early childhood will marry younger, start reproduction earlier, have shorter birth intervals, and will have a higher risk of giving birth out of wedlock.We use the Stockholm Historical Database (SHD), which contains records of the total population of the city of Stockholm for the period 1878-1926, to investigate our hypotheses. To analyze the impact of high extrinsic mortality during early childhood on the marriage and reproductive behavior, we select individuals who were born in the city of Stockholm between 1878-1905, who had at least one sibling (birth date and possible death date had to be known), and whose father’s socioeconomic status is known. Separate event history models will be estimated for men and women.

Life history theory predicts that individuals adapt their life trajectories to the local ecology (Schaffer 1983). One important ecological factor that influences the timing of certain life events is extrinsic mortality (Promislow and Harvey 1990). Extrinsic mortality is a result of environmental hazards such as infectious diseases, predation, war, famine or accidents which is an age-specific risk that is not under the individual’s control (Quinlan,2007; Gurven and Fenelon, 2009). Previous studies in preindustrial and contemporary societies have shown that exposure to high extrinsic mortality during early childhood (0-7 years) can fasten individuals’ life history strategies characterized by earlier age of menarche, first pregnancy and birth (Chisholm, Quinlivan et al. 2005; Belsky, Steinberg et al., 2010; Nettle, 2010; Quinlan, 2010; Nettle, Coall et al., 2011; Störmer and Lummaa, 2014).The present study investigates the impact of high extrinsic mortality during early childhood on the age at first marriage, age at first birth, out of wedlock fertility, and the length of birth intervals. Extrinsic mortality is measured in two ways: (1) mortality on the district level, and (2) mortality on the family level. On the district level we utilize crude death rates, and on the family level we study the effect of mother’s death, father’s death and siblings’ death. We predict that individuals who were exposed to high extrinsic mortality during early childhood will marry younger, start reproduction earlier, have shorter birth intervals, and will have a higher risk of giving birth out of wedlock.We use the Stockholm Historical Database (SHD), which contains records of the total population of the city of Stockholm for the period 1878-1926, to investigate our hypotheses (Thorvaldsen, 1998). The city of Stockholm is particularly interesting due to the high mortality and high illegitimacy rates compared to other European cities during our research period. To analyze the impact of high extrinsic mortality during early childhood on the marriage and reproductive behavior, we select individuals who were born in the city of Stockholm between 1878-1905, who had at least one sibling (birth date and possible death date had to be known), and whose father’s socioeconomic status is known. Separate event history models will be estimated for men and women.

References

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Chisholm, J. S., J. A. Quinlivan, R. W. Petersen and D. A. Coall (2005). "Early stress predicts age at menarche and first birth, adult attachment, and expected lifespan." Human Nature 16(3): 233-265.

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Störmer, C. and V. Lummaa (2014). "Increased mortality exposure within the family rather than individual mortality experiences triggers faster life-history strategies in historic human populations." PloS one 9(1): e83633.

Thorvaldsen, G. (1998). "Historical databases in Scandinavia." The History of the Family 3(3): 371-383.

Presented in Session 1138: Health, Wellbeing, and Morbidity