Prenatal loss of father during World War One is predictive of a reduced lifespan in adulthood

Abstract

Although early-life stress is known to alter health, its long-term consequences on mortality remain largely unknown. Thanks to unique French legislation established in 1917 for war orphans and children of disabled soldiers, we were able to study the adult mortality of individuals born in 1914-1916 whose fathers were killed during World War 1. Vital information and socio-demographic characteristics were extracted manually from historical civil registers for 5,671 children born between 1 August 1914 and 31 December 1916 who were granted the status of "pupille de la Nation" (orphan of the Nation). We used a database comprising 1.4 million deceased soldiers to identify war orphans and collect information on their fathers and then paired each orphan with a nonorphan from the same birth register matched for date of birth, sex, and mother's age at the infant's birth. Mortality between ages 31 and 99 y was analyzed for 2,365 orphan/nonorphan pairs. The mean loss of adult lifespan of orphans who had lost their father before birth was 2.4 y (95% CI: 0.7, 3.9 y) and was the result of increased mortality before age 65 y. Adult lifespan was not reduced when the father's death occurred after the infant's birth. These results support the notion that intrauterine exposure to a major psychological maternal stress can affect human longevity.

Keywords: World War One; adult mortality; historical cohort; intrauterine programming; maternal bereavement.

Fig. 1.

Historical material used: Examples of an orphan’s birth certificate (A) and the military record of the orphan’s father (B). (A) Birth certificate of a pupille de la Nation, André L., born of Gabriel L. on 31 August, 1914, in Bordeaux. The tribunal of the city of Versailles granted him pupille de la Nation status in 1923. That information was automatically transmitted by the Versailles tribunal to the city hall of Bordeaux and was transcribed by a civil servant in the upper left margin of the birth certificate. Similarly, notification of André L.’s marriage (in 1945) and death (in 1974) were transmitted (both by the city hall of the 16th district of Paris) to the city hall of Bordeaux, which noted these life events on the left margin of the birth certificate a few days after they occurred (© archives Bordeaux métropole – Bordeaux 1 E 427). (B) We searched for the father of André L., Gabriel L., by name and age in the database of French soldiers who died during WW1 (available at www.memoiredeshommes.sga.defense.gouv.fr/en/article.php?larub=80). The database yielded the image of the father’s record (selected sections are shown). Gabriel L. was killed in action on 9 June 1915.

Fig. S1.

Flowchart showing the definition of the cohorts of war orphans and MNOs. Pupilles were by definition children who survived from birth to their being adopted by the Nation at some point in childhood (on average at ∼ age 5 y). Their probability of death before age 31 y is conditional on having being adopted (354/2721 = 13%) and therefore was expected to be lower than the unconditional probability of death before age 31 y measured in MNOs (1,977/5,671 = 34.9%).

Fig. S2.

Birth dates of prenatal and postnatal orphans and MNOs. The majority of orphans were conceived before August 1914 (the beginning of the war) and thus were born before May 1915. The observed abrupt decline in the monthly number of orphan births in May 1915 paralleled the decline observed at the country level (66). The distributions of dates of birth were different in prenatal and postnatal orphans. By design, the distribution of dates of birth is identical in orphans and MNOs for both types of orphans. The number of prenatal orphans born in a given month was determined by both the number of conceptions 9 mo before and the father’s risk of death during pregnancy. Men who impregnated women just before the war began had a prewar fertility and were at risk during the woman’s entire pregnancy. The observed peak in the birth of prenatal orphans in February–April 1915 therefore was expected. In contrast with prenatal orphans, the monthly number of postnatal orphans was approximately constant before May 1915. MNOs are matched to orphans by district and date of birth, so any cofounding associated with the place and date of birth (e.g., changing disease environment) is removed in the comparison of orphans and MNOs. The solid line shows the Gaussian kernel density estimate.

Fig. 2.

Mean difference in lifespan between war orphans and MNOs according to age at father’s death. Data are shown as mean ± SE.

Fig. 3.

Variation with age of the difference between orphan and MNO remaining lifespans, by sex.

Fig. S3.

Type of birth and home address of parents for orphans and MNOs born in three contrasted districts of Paris. For orphan/MNO pairs born in three districts of Paris (fifth, n = 112; seventh, n = 43; and eighth, n = 111) with contrasted delivery modes (hospital, midwife’s house, at-home births), the home address of the parents was computerized (n = 532). Addresses were geocoded using Google Maps API, called from R with the geocode function of the ggmap package (67). The addresses for which this geocoding failed were examined manually (n = 52): 33 streets whose name had changed since 1914 were identified by comparing 1914 and modern-day maps, and the Google Map geocoding was relaunched accordingly. Addresses in streets that had disappeared were geocoded manually (n = 7). Finally, addresses in streets that we failed to identify on 1914 maps were set at the district/town center (n = 12). (A) Number of hospital births, homebirths, and births at midwives’ houses for orphans and MNOs. (B) Districts with hospitals or midwives’ houses (i.e. the fifth and eighth districts) recruited women living in neighboring districts and suburban towns. In the seventh district all births were homebirths. The three selected districts are outlined in black. (C) Among parents domiciled outside Paris were war refugees who had settled in Paris but were still domiciled in their region of origin. (The dotted line shows the stabilized frontline from October 1914.)

Fig. S4.

Process for the identification of orphans’ fathers. We manually searched for the father of each of the 5,671 included pupilles de la Nation (A) in the online database of soldiers who died during WW1 (B) (available at www.memoiredeshommes.sga.defense.gouv.fr), based on the father’s name and age, to determine whether the pupille was an orphan and to retrieve the father’s date and cause of death. The record of each soldier also contains his date and place of birth. In the cases where the search yielded several candidates, or when uncertainty remained as to whether the soldier found was indeed the father of the pupille, we took advantage of the fact that the birth certificates of candidate fathers found in the database (commonly born 1880–1895) (C) are available on the websites of the local archives (“Archives départementales”) of their place of birth. We manually examined the birth certificate of each candidate to check whether his wife (whose name is given on the marriage notification on the birth certificate) was named as the mother of the pupille on the pupille’s birth certificate. This method yielded certain identification for all pupilles de la Nation whose parents married, whether before or after birth. Because of a recent digitization program, images of >90% of birth registers before 1900 (C) are now available online (current completion by region may be seen at www.archivesdefrance.culture.gouv.fr, from which local websites may be reached). Marriages began to be noted on the birth certificates of those marrying in 1897, thus providing a simple, systematic, positive method of verifying the linkage between birth registers and the WWI military deaths database. For a pupille de la Nation whose parents never married but who was recognized by his father, the act of recognition (which mentions the date and place of birth of the father and thus yields positive identification) was examined, provided that the recognition took place in one of the districts included in the study.