Physical Markers at Young Age and Survival to 100: A Study of a New Historical Data Resource The U.S

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Physical Markers at Young Age and Survival to
100 A Study of a New Historical Data Resource
(The U.S. WWI Draft Cards)

• Dr. Natalia S. Gavrilova, Ph.D.
• Dr. Leonid A. Gavrilov, Ph.D.
• Center on Aging
• NORC and The University of Chicago
• Chicago, Illinois, USA

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Approach

• To study success stories in long-term avoidance
  of fatal diseases (survival to 100 years) and
  factors correlated with this remarkable survival
  success

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Centenarians represent the fastest growing age
group in the industrialized countries

• Yet, factors predicting exceptional longevity and
  its time trends remain to be fully understood
• In this study we explored the new opportunities
  provided by the ongoing revolution in information
  technology, computer science and Internet
  expansion to explore early-childhood predictors
  of exceptional longevity

Jeanne Calment (1875-1997)
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Revolution in Information TechnologyWhat does
it mean for longevity studies?

• Over 75 millions of computerized genealogical
  records are available online now!

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Computerized Genealogies as a Resource for
Longevity Studies

• Pros provide important information about family
  and life-course events, which otherwise is
  difficult to collect (including information about
  lifespan of parents and other relatives)
• Cons Uncertain data quality
  Uncertain validity and generalizability
  

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For longevity studies the genealogies with
detailed birth dates and death dates for
long-lived individuals (centenarians) and their
relatives are of particular interest

• In this study 1,001 genealogy records for
  centenarians born in 1875-1899 were collected and
  used for further age validation

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Steps of Centenarian Age Verification

• Internal consistency checks of dates
• Verification of death dates linkage to the
  Social Security Administration Death Master File
  (DMF)
• Verification of birth dates linkage to early
  Federal censuses (1900, 1910, 1920, 1930)

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Results of Centenarian Age Verification
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Conclusions of the Age Verification Study

• Death dates of centenarians recorded in
  genealogies always require verification because
  of strong outliers (1.3, misprints)
• Birth dates of centenarians recorded in
  genealogies are sufficiently accurate - 92 are
  correct for the remaining 8 only one-year
  disagreements
• Quality of genealogical data is good enough if
  these data are pre-selected for high data quality

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Predictors of Exceptional Longevity
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Within-Family Study of Exceptional Longevity
Cases - 198 Centenarians born in U.S. in
1890-1893 Controls Their own siblings Method
Conditional logistic regression Advantage
Allows researchers to eliminate confounding
effects of between-family variation
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Design of the Study
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A typical image of centenarian family in 1900
census
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First-born siblings are more likely to become
centenarians (odds 1.8)
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Birth Order and Odds to Become a Centenarian
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Can the birth-order effect be a result of
selective child mortality, thus not applicable to
adults?

• Approach
• To compare centenarians with those siblings only
  who survived to adulthood (age 20)

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First-born adult siblings (20years) are more
likely to become centenarians (odds
1.95)
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Are young fathers responsible for birth order
effect?
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Birth order is more important than paternal age
for chances to become a centenarian
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Are young mothers responsible for the birth order
effect?
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Maternal Age at Persons Birth and Odds to Become
a Centenarian
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Birth order effect explainedBeing born to young
mother!
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Even at age 75 it still helps to be born to young
mother (age 25
Question

• Families were quite large in the past,
  particularly those covered by genealogical
  records (large family size bias).
• Is the "young mother effect" robust to the family
  size, and is it observed in smaller families too?
• Or is it confined to extremely large families
  only?
• Approach
• To split data in two equal parts by median family
  size (9 children) and re-analyze the data in each
  group separately.

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Results

• In smaller families (less than 9 children) the
  effect of young mother is even larger
• Odds ratio 2.23, P0.004 95CI 1.30 - 3.98
• Compare to larger families (more than 9
  children)
• Odds ratio 1.72, P0.11 95CI 0.88 - 3.34
• Conclusion
• "Young mother effect" is not confined to
  extremely large family size

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New Striking Findings Invitation for discussion
and brain-storming!

• The favorable "Young Mother Effect" is
  particularly strong when parents have
  particularly large differences in their lifespan

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Odds Ratio to live to 100 years if born to young
motheras a function of maternal and paternal
lifespans (tertiles)
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Being born to Young Mother Helps Laboratory Mice
to Live Longer

• Source
• Tarin et al., Delayed Motherhood
  Decreases Life Expectancy of Mouse Offspring.
• Biology of Reproduction 2005 72 1336-1343.

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Physical Characteristics at Young Age and
Survival to 100
A study of height and build of centenarians when
they were young using WWI civil draft
registration cards
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Height What to Expect

• Height seems to be a good indicator of
  nutritional status and infectious disease history
  in the past.
• Historical studies showed a negative correlation
  between height and mortality.
• Hence we may expect that centenarians were taller
  than average

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Build What to Expect

• Slender build may suggest a poor nutrition during
  childhood. We may expect that centenarians were
  less likely to be slender when young.
• On the other hand, biological studies suggest
  that rapid growth may be harmful and somewhat
  delayed maturation may be beneficial for
  longevity.

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WWI Civilian Draft Registration

• In 1917 and 1918, approximately 24 million
  men born between 1873 and 1900 completed draft
  registration cards. President Wilson proposed the
  American draft and characterized it as necessary
  to make "shirkers" play their part in the war.
  This argument won over key swing votes in
  Congress.

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Information Available in the Draft Registration
Card

• age, date of birth, race, citizenship
• permanent home address
• occupation, employer's name
• height (3 categories), build (3 categories), eye
  color, hair color, disability

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Draft Registration CardAn Example

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Data Sources

• Social Security Administration Death Master File
• WWI civil draft registration cards (completed for
  almost 100 percent men born between 1873 and
  1900)

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Study Design

• Cases men centenarians born in 1887 (randomly
  selected from the SSA Death Master File) and
  linked to the WWI civil draft records. Out of
  120 selected men, 19 were not eligible for draft.
  The linkage success for remaining 101 records was
  75 (76 records)
• Controls men matched on birth year, race and
  county of WWI civil draft registration

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Height and Survival to 100
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Body Build and Survival to 100
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Results of multivariate study
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Conclusion

• The study of height and build among men born in
  1887 suggests that rapid growth and overweight at
  young adult age (30 years) might be harmful for
  attaining longevity

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Month of Birth and the Likelihood
to Become a Centenarian
among WWI draft participants
Method Conditional logistic regression for odds
to become a centenarian. Controls men matched
on birth year, race and county of draft
registration. Adjusted for occupation, height and
build. 76 observations
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Month of Birth and the Likelihood
to Become a Centenarian
for Adult Siblings
Method Conditional logistic regression for odds
to become a centenarian, using siblings as
within-family control. 787 observations
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Final Conclusion

• The shortest conclusion was suggested in the
  title of the New York Times article about this
  study

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Acknowledgments

• This study was made possible thanks to
• generous support from the National Institute on
  Aging and the Society of Actuaries

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