Mother’s Death, Sibling Careand Child Survival in the Past

Québec population

A.Gagnon2 , S. Pavard2, B. Desjardins3, E. Heyer2

1 Population Studies Centre, Department of Sociology, University of Western Ontario, Canada

2 UMR 5145 Éco-Anthropologie Equipe « génétique des populations humaines » Musée de l’Homme, France

3 Programme de recherches en démographie historique, Université de Montréal, Montréal, Canada.

Rationale for this study

• Biodemography– Natural selection at different ages of life, and,

in particular, the origins of menopause– Idea: Lost of maternal care (by maternal

mortality) decreases the chances for survival of already borne children

– In the curse of human evolution, selection for stopping reproduction (when it becomes too dangerous)

Death of the mother is a relatively rare event

Need many cases to attain statistical significance

Few possibilities to make a retrospective study The most reliable person to be questioned on child survival (the mother) is dead, not availableConsequently, very few studies addressed this question

Way to overcome these problems: demographic database with longitudinal observation

Difficulty of the study

DATA:

Registre de population du Québec ancien (1608-1800), PRDH, Université de Montréal

-Contains > 712,000 records (birth, marriage and death certificates)

Approximately 400,000 births available

But,

- Many children retrieved because their survival was clearly affected by confounders (short birth interval, etc.)

In total: 83,229 individual records of live birth (from 1625 to 1759)

Among them, 9,840 children lost their mother before age fifteen (still large sample size)

… makes up for lack of qualitative data…

Survival to age 15 according to the survival statusof the mother

Table 2. Odds Ratio calculated for each period by the age of children and by the ACDM value. Regular and bold values are results calculated for periods before and after the death of the mother respectively.

Periods ACDM

(Age of the child at mother’s death)

N Post-

neonatal Toddler

Early

childhood

Late

childhood

Neonatal 222 6.04**** 1.64* 1.80 1.27

1.62 Post-

neonatal 303

3.98*** 2.21**** 2.45* 1.77*

1.82* Toddler 1211 1.48****

2.62** 1.72* 1.20*

1.58 Early

childhood 1402 1.41**** 1.63****

2.68** 1.46**

1.11 Late

childhood 6702 1.26**** 1.23** 1.26*

1.45*

Odds ratio of dying of motherless children (against children whose mother was alive)

*p < 0.05

**p < 0.005

***p < 0.0005

****p < 0.0001

: Deaths occurring after mother’s death

General mortality (mother’s alive)

Deaths occurring before mother’s death

Deaths occurring after mother’s death

Time

Mother’s death takes place here

General mortality level (mother’s alive)

Deaths occurring before mother’s death Among the deaths

occurring after mo-ther’s death, many are due to the fact that mortality is higher in some fa-milies and not to maternal care lack.

Time

Mother’s death takes place here

Deaths occurring after mother’s death

General mortality (mother’s alive)

Mother’s death takes place here

Corrected number of deaths: Deaths of children occurring because of mother’s death (lack of maternal care)

Time

Periods

ACDM N Post-

neonatal Toddler

Early

childhood

Late

childhood

Mortality (28th day - age 15)

(0/00)

Neonatal 222 5.52**** 1.38 1.60 1.27 480

1.34 Post-

neonatal 303

3.81*** 1.93* 2.24* 1.77** 450

1.54 Toddler 1211 1.19**

2.41** 1.51* 1.20 340

1.38 Early

childhood 1402 1.13 1.36*

2.48* 1.46** 320

1.11 Late

childhood 6702 0.98 0.98 1.06

1.45** 260

Mortality (28 days - 5 years)

(0/00)

*p < 0.05

**p < 0.005

***p < 0.0005

****p < 0.0001

: Deaths occurring after mother’s death

Odd ratios of dying for motherless children corrected for family heterogeneity

Age group

Gender difference in the risk of death for motherless kids?

Survival to age 15 per sex according to the survival status of the mother

Survival up to age 15 (this includes only those who died)

Period

Post-neonatal Toddler Little child childACDM

(Age of the childat mother’s

death) Boys Girls²

valueBoys Girls

²

valueBoys Girls

²

valueBoys Girls

²

value

Neonatal 310 307 0.000 - - - - - - - - -

- - -Post-neonatal

246 244 0.000- - - - - - - - -

86 82 0.01Toddler 44 47 0.039

128 72 0.647 69 3.69* 12 46 3.95*

- - -Little child - - - - - -

100 323 5.28*26 81 4.09*

- - -Child - - - - - - - - -

27 61 4.14*

Percentage of increase of mortality related to mother’s death

Age group

*p < 0.05

**p < 0.005

***p < 0.0005

****p < 0.0001

: Deaths occurring after mother’s death

Two hypotheses

• 1) Girls could be more “psychologically” affected by the death of the mother than boys (Child Bereavement Study, Worden, 1996)

• 2) Girls took up the responsibility of the missing mother Entails a higher risk of death by “investing in someone else” or by cross infections

Sibling care?

Proportional hazard regression (or Cox regression) estimates of the odds of dying between age 3 and 15 given the number of elderly siblings

Mother ALIVE Boys (27 226 ) Girls (27778 ) Exp (B) Sign. Exp (B) Sign.

Mother’s age <25 0.0054 0.1633

25-35 1.20 0.0013 1.11 0.0673 >35 1.15 0.0390 1.10 0.1463

Olderbrothers

None 0.1931 0.5544 1-2 0.96 0.5647 1.06 0.4135 3-5 0.85 0.0631 1.09 0.2998

6 or + 1.17 0.4809 0.83 0.4541 Older sisters

None 0.3793 0.1910 1-2 0.91 0.2022 1.10 0.1511 3-5 1.02 0.8215 0.96 0.6558

6 or + 0.85 0.5887 0.88 0.6921

No significant impact…

Proportional hazard regression (or Cox regression) estimates of the odds of dying between age 3 and 15 given the number of elderly siblings

Mother DECEASED Boys (4 337) Girls (4 357) Exp (B) p Exp (B) P

Mother’s age <25 0.9524 0.8702

25-35 1.02 0.8761 1.01 0.9022 >35 1.05 0.7557 1.07 0.6249

Olderbrothers

None 0.0044 0.0022 1-2 0.40 0.0010 0.45 0.0020 3-5 0.35 0.0004 0.36 0.0002

6 ou + 0.50 0.0948 0.53 0.1270 Older sisters

None 0.0047 0.0010 1-2 0.40 0.0011 0.43 0.0011 3-5 0.39 0.0011 0.35 0.0002

6 ou + 0.22 0.0071 0.19 0.0081

Risks of death for children whose mother died (Cox)

Included variables : B SE Wald ddl p Exp(B) - Age of the mother at birth

.032 .007 20.132 1 .000 1.032

- Age of the child at the death of the mother

-.309 .011 721.817 1 .000 .734

- Older brothers None 7.427 3 .059 1 – 2 -.072 .087 .688 1 .407 .930 3 – 5 -.278 .112 6.214 1 .013 .757 6 or + -.345 .235 2.158 1 .142 .708 - Older sisters None 13.752 3 .003 1 – 2 -.101 .086 1.376 1 .241 .904 3 – 5 -.332 .113 8.636 1 .003 .718 6 or + -.802 .288 7.771 1 .005 .449

Conclusion

• Mother’s death and child survival:– The younger was the child when losing his/her mother, the

higher was the risk– But significantly diminished chances for survival over all

childhood

• Sex differentials and “sibling care”:– Boys generally had a higher mortality– They died sooner than girls (endogenous causes)– But girls seemed to be more affected by mother’s death (two

hypotheses)– Older sisters appeared to offer a “protector effect”

End