Using Historical Records to Reconstruct Early Life SES Exposures

in Decedents: Preliminary Findings from a Pilot Study

Kathryn Rose and J. Stephen Perhac

University of North Carolina at Chapel Hill

Background

• Early life socioeconomic conditions associated with increased risk of chronic diseases in adulthood

• In most ongoing epidemiologic studies early life SES not ascertained at study inception– Collect from study participants while study is

ongoing – Obtain from historical records

• Linkage of death certificates with 1900-1920 individual census records (Hill, 2000; Preston,1996)– Elderly, white men: 70% linkage– Elderly black men: 56% linkage

• Study of link between childhood SES and Alzheimer’s disease (Moceri, 2001)– Attempted linkage with birth certificates and

declassified 1910-20 census records• 86% of participants linked to birth certificates and/or

census record• No significant variation by gender, age or education

Can Early Life SES Be Obtained From Historical Records?

Rationale for Current Pilot Study

• Feasibility of using public records to obtain early life SES information:– Accessibility– Cost ($$$ and time)– Availability of parental SES data

• Completeness• Comparability to data from other sources

• What are the sociodemographic determinants of successful linkage?

Participants

• Atherosclerosis Risk in Communities (ARIC) Study – Baseline examination 1987-89– Participants born between 1922 and 1944

• 451 participants from NC field center who subsequently died – Born between 1922-1935 (N=334)– Born in NC (N=319)

or

Search Strategy

Death Certificates SS-5s

Database for searching records

containing parental SES

NC Born

Request NC Birth Certificates

Born 1922-1935

Search 1930 Census

Attempting Linkage to Records with Parental SES Information

• Sources:– Death Certificates

• Available for > 99% of decedents

– Social Security application (SS-5) data• Obtained for 99% of decedents

• Information abstracted:– Mother and father’s names– Participant data:

• Name(s), date and place of birth, race, gender

Searching for NC Birth Certificates

Death Certificates SS-5s

Database for searching records

containing parental SES N=451

NC BornN=319

Request NC Birth Certificates

NC Birth Certificate Search

• 269 of 321 (84%) requested records found– Yield of usable records lower

• (N=253 - 79%)

– Yield:• Higher for whites than blacks (81% vs. 72%)• Higher for men than women (81% vs. 76%)• Did not not vary by education

– 95% contained parental occupational data

Searching for 1930 Census Records

Death Certificates SS-5s

Database for searching records

containing parental SES

Born 1922-1935

N=334

Search 1930 Census

Linkage with 1930 Census Records

• Accessed using a proprietary website with computerized index

• Criteria Used to determine match:– Place of birth match vs. census address– Match on both parents’ names – Match on race– If participant born at the time of census

• Did age and name match?

Linkage with 1930 Census Records

• 238 of 334 records (71%) found on initial searches– Yield:

• Higher for whites (74%) than blacks (57%) • Higher for men (73%) than women (68%)• Lower for those with less than HS education

(69%) than for those with 12+ years of education (72%)

• Highest between 1927 and 1931 (80% +)

Sociodemographic Information Available from 1930 Census Records

• Virtually complete and legible

• Socioeconomic information• Home ownership• Household size• Literacy of mother and father• Occupational data on parents

– Job title – Industry– Whether an owner or an employee– Current employment status

NC Born

N=319

Born 1922-1935

N=334

269 Birth Certificates

Obtained (84%)

238 Census Records Located

(74%)

Search on 382 decedent records

•9% not located

•91% birth certificate and / or census record

Summary: Data Linkage

NC BornN=319

Born 1922-1935

N=334

182 decedents searched

on both sources

•79% both birth certificate and census record

•19% census record only

•1% birth certificate only

•1% no birth certificate or census record

Strengths and Limitations: Birth Certificate Data

Strengths• Data collected

directly from parents at time participant was born

• Records archived by state

Limitations • Limited SES data• Variation in content

across time and place• Access rules vary by

state• During this time period

records not always filed at birth

• Costly

Strengths and Limitations: Census Data

Strengths• Data collected in a

standardized manner across U.S. by trained census takers

• Large amount of parental SES-related data

• Inexpensive• Every person is

indexed

Limitations • Records are hand-

written• Data abstraction is

tedious• Limited ability to

track those not born in close proximity to census

• Only declassified after 72 years

Next Steps

• Continued search of census records• Comparison of the parental occupational

data from different sources – Census vs. birth certificate

– 1920 vs. 1930 census

– Historical records vs. those reported by participants

Conclusions

• It is feasible to use birth certificates and early census records as a source of early life SES information– Accessible – Parental SES information is complete– Labor-intensive and potentially expensive

• Potential use in such data is missing due to loss to follow-up

Acknowledgements

• UNC at Chapel Hill Program on Demographics and Economics of Aging Research

• Dr. Gerardo Heiss• The ARIC Study• B. Renee Ferguson • Brigitt Heier