mother’s death, sibling care and child survival in the past québec population
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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
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