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Early-Life Experience and Old-Age Mortality: Evidence from Union Army Veterans
LOGO
Dejun Su, Ph. D.
The University of Texas-Pan American
KEY FINDINGS
1. To examine the relation between risk exposures prior
to enlistment and old-age survival among Union Army
veterans, and evaluate the robustness of this relation
with and without the incorporation of SES in later life.
2. To identify the life stage(s) in later life when early-life
exposures can have a significant impact.
3. To delineate the trends in the relation between earlylife experience and old-age survival by comparing
findings from Union Army veterans with corresponding
findings from more recent birth cohorts.
DATA & METHODS
Keywords: risk exposures in early life; old-age mortality;
life course perspective; Union Army Veterans.
BACKGROUND
The data used in this study comes from a subset of the
Union Army Sample (Fogel 2000, 2001) that contains
detailed records on major life events from childhood to
death for roughly 12,000 Union Army soldiers who fought
the American Civil War.
In light of the literature on the life-course approach to
old age survival, three questions are in need of further
clarification:
 Whether and to what extent socioeconomic
conditions in later life can modify the observed
impact of early-life conditions on survival in later
life.
 The second pending issue pertains to the
identification of the life stage(s) in later life when
risk exposures in early life can have a significant
impact on health and survival.
 Whether and to what extent the relation between
risk exposures in early life and old-age survival
have changed over time.
Figure 1: Old Age Mortality in a Life Course Perspective
Early-life conditions
Birth
Mean Age
0
Year
1805-1850
Enlistment
Discharge
24
26
1861-1865
1 st Physical Exam
Old-Age Conditions
47
1862-1900
61
1900
Death
War Experience
Old-Age Conditions
Veterans who were born in Germany and Ireland had
significantly higher mortality risk in old age than their
native-born counterparts.
Coming from big cities prior to enlistment–defined as
one of the 25 largest cities in 1860 with a minimum
population of 37,000–is associated with an elevated
mortality risk of 15 percent. But the survival
disadvantage associated with coming from big cities
only becomes significant in the period from 1900 to
1910, but not in the period after 1910.
Coming from North Atlantic region is associated with a
higher mortality risk as compared to coming from
other regions prior to enlistment.
Height at enlistment shows a negative association
with the chance of survival after 1900.
Veterans who were farmers prior to enlistment had the
lowest mortality risk in old age.
FIGURES (1)
76
1900-1946
List of Variables
Early-Life
Conditions
Being born in autumn (September to November) is
associated with a six percent lower mortality risk than
being born in spring (March to May), this survival
advantage associated with autumn-born, however, did
not come into effect until late into old age.
Waiting Time to Death
The focal dependent variable is the hazard rate of dying
at any time after 1900 given that a veteran has survived
to 1900, which is modeled in the Cox Proportional
Hazard (CPH) analysis as a function of exposures to risk
factors across three life stages: early life, wartime
experience and socioeconomic conditions circa 1900.
Life Stages
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War Experience
Variables
Season of birth, country of birth, region of residence,
rural or urban, height at enlistment, and occupation
prior to enlistment.
Age at enlistment, rank at enlistment, injured during war,
prisoner of war, exposed to higher casualty
BMI, living in big cities, residential regions, occupation,
marital status, literacy, house ownership, age at death
CONCLUSIONS
FIGURES (2)
Figure 2: Birth Season and Height at Enlistment
68
67.8
Figure 3: Occupational Difference in Height
F arm e r
P ro fe ssio nal
67.4
67
66
65
16
19
22
67
S pring
S um m er
A utum n
B irth S easo n
W inter
25
28
31
34
A ge at E nlistm ent
TABLE
Table 1: Risk Exposures in Early Life and Mortality: A Sensitivity Analysis
Explanatory Variables
Age in 1900
61.2
Birth Season
Predicting Survival After 1900
1900 to 1910
After 1910
Model 1
(Early Life)
Model 2
(Full Model)
Model 3
(Full Model)
Model 4
(Full Model)
1.09***
1.09***
1.09***
1.09***
26.9
Omitted
Omitted
Omitted
Omitted
Summer
23.7
1.00
1.00
0.97
1.02
Autumn
24.1
0.94**
0.95*
0.98
0.94*
Winter
25.3
0.97
0.98
0.93
1.00
***
***
***
***
Omitted
Omitted
Omitted
Omitted
Birth Country
United States
83.2
Britain
2.7
0.99
0.97
1.03
0.94
Canada
2.7
1.01
0.99
0.97
0.99
Germany
5.7
1.09**
1.09*
1.06
1.11*
Ireland
3.7
1.21***
1.21***
1.40***
1.10
Other Countries
2.0
0.86**
0.83**
1.06
0.72***
Coming from Big Cities
6.6
1.15***
1.12**
1.21**
1.06
***
***
***
**
Omitted
Omitted
Omitted
Omitted
0.91*
0.92
0.84
0.96
Residential Regions
North Atlantic
27.5
South Atlantic
4.3
North Central
58.3
0.90***
0.94
1.04
0.90*
South Central
4.1
0.89**
0.90
1.16
0.82**
Other
5.8
0.77***
0.75***
0.63***
0.77***
***
***
**
***
Short
32.5
Omitted
Omitted
Omitted
Omitted
Middle
33.9
1.02
1.01
0.90**
1.05
Tall
33.6
1.08***
1.10***
1.00
1.14***
***
***
***
***
Farmer
59.8
Omitted
Omitted
Omitted
Omitted
Artisan
17.3
1.13***
1.14***
1.20***
1.11***
Manual Labor
12.0
1.09**
1.08**
1.14**
1.06
Professional
6.1
1.08*
1.04
1.21**
0.96
Other
4.8
1.16***
1.17***
1.19**
1.17**
10,535
9,022
9,022
6,440
2,666
2,452
1,403
1,278
20
48
48
48
Chi-square
Degree of Freedom
Whereas some of the effects such as being born in
Ireland, coming from big cities, and occupation mainly
influence survival between 1900 and 1910, the effects
of being born in autumn, residential locations, and
being the tallest third are more salient on survival after
1910.
Compared to corresponding findings from more recent
cohorts, the exceptional rigidity of the effects of risk
exposures prior to enlistment on old-age mortality
among the veterans highlights the harshness of living
conditions in their early life.
ACKNOWLEDGEMENT
*
Spring
Number of Cases
Veteran’s risk exposures prior to enlistment as
approximated by birth season and country, residential
location, height at enlistment, and occupation prior to
enlistment significantly influence their chance of
survival after 1900.
Hazard Ratio
Mean or %
Occupation at Enlistment
67.2
M anualL ab o r
68
Height Adjusted by Age
67.6
A rtisan
O the r
69
H eight in Inches
This study examines the relation between risk exposures
in early life and hazard of mortality among 12,000 Union
Army veterans aged 50 and over in 1900. Veterans’ risk
exposures prior to enlistment as approximated by birth
season and country, residential location, height at
enlistment, and occupation prior to enlistment significantly
influence their chance of survival after 1900. These
effects are robust irrespective of whether or not wartime
stress and socioeconomic well-being circa 1900 are taken
into account, however, they are sensitive to the particular
life stage in later life that has been selected for survival
analysis. Compared to corresponding findings from more
recent cohorts, the exceptional rigidity of the effects of
risk exposures prior to enlistment on old-age mortality
among the veterans highlights the harshness of living
conditions in their early life.
STUDY OBJECTIVES
H eig h t in In ch es
ABSTRACT
11,978
Source: The Union Army Sample. * p<0.1; ** p<0.05; *** p<0.01.
This study was supported by a grant from the National
Institute on Aging (grant number P01 AG10120). The
paper was adapted from my dissertation “Old-age
Mortality in a Life Course Perspective: Union Army
Veterans 1805-1946.” I thank Linda Waite, Robert Fogel,
Patrick Heuveline, and Tom Chappelear for their
comments. Possible errors in this study are sole
responsibility of the author.
CONTACT INFORMATION
Mailing Address:
Department of Sociology
The University of Texas- Pan American
1201 W. University Drive SBS 341
Edinburg, TX 78541
Email: [email protected]
Phone: (956) 380-8798
Fax: (956) 381-2343