Elizabeth Breeze, MSc, CStat, Astrid E. Fletcher, PhD, David A. Leon, PhD,
Michael G. Marmot, PhD, MBBS, Robert J. Clarke, MD, MRCP,
and Martin J. Shipley, MSc
Elizabeth Breeze, Astrid E. Fletcher, and David A.
Leon are with the Department of Epidemiology and
Population Health, London School of Hygiene and
Tropical Medicine, London, England. Michael G.
Marmot and Martin J. Shipley are with the Interna-
tional Centre for Health and Society, Department
of Epidemiology and Public Health, University Col-
lege Medical School, London. Robert J. Clarke is
with the Clinical Trial Service Unit and Epidemio-
logical Studies Unit, University of Oxford, Oxford,
England.
Requests for reprints should be sent to Eliza-
eth Breeze, MSc, CStat, London School of Hy-
giene and Tropical Medicine, Keppel Street, Lon-
don WC1E 7HT, England (e-mail: elizabeth.
eeze@
lshtm.ac.uk).
This article was accepted May 24, 2000.
A B S T R A C T
Objectives.This study examined (1)
the relation of employment grade in
middle age to self-reported poor health
and functional limitations in old age and
(2) whether socioeconomic status at ap-
proximately the time of retirement mod-
ifies health differentials in old age.
Methods. Survivors of the Whitehall
Study cohort of men were resurveyed.
Respondents were aged 40 to 69 years
when they were originally screened in
1967 to 1970.
Results. Compared with senior ad-
ministrators, men in clerical or manual
(low-grade) jobs in middle age had
quadruple the odds of poor physical per-
formance in old age, triple the odds of
poor general health, and double the odds
of poor mental health and disability. At
most, 20% of these differences were ex-
plained by baseline health or risk fac-
tors. Men who moved from low to mid-
dle grades before retirement were less
likely than those who remained in low
grades to have poor mental health.
Conclusions. Socioeconomic status
in middle age and at approximately re-
tirement age is associated with mo
id-
ity in old age. (Am J Public Health. 2001;
91:277–283)
Fe
uary 2001, Vol. 91, No. 2 American Journal of Public Health 277
There is a small but growing body of evi-
dence from the United Kingdom that socioeco-
nomic differentials in mortality persist into old
age1–3 and may even be widening.4,5 Although
ate ratios tend to be smaller for older people
than for younger people in the United Kingdom
and the United States,4–6 absolute differentials
can still be large.5
There is little equivalent information on
self-reported mo
idity. Analyses of cross-
sectional studies show that self-reported health
and disability, respiratory function, and blood
pressure are all worse among older people in
disadvantaged socioeconomic groups.7,8Analy-
ses of the Office for National Statistics Lon-
gitudinal Study in England and Wales showed
that adverse socioeconomic circumstances were
associated with self-reported limiting long-
term illness after a 20-year follow-up period
among survivors.9
The first Whitehall Study, an investiga-
tion of male British civil servants that was ini-
tiated in the late 1960s, showed an inverse mor-
tality gradient (all causes and major causes)
across employment grades.10 The Whitehall II
Study, following a later cohort, revealed gra-
dients in mo
idity in middle age across so-
cioeconomic groups.11,12 A resurvey of the sur-
vivors of the first cohort enabled us to study the
long-term effects of employment grade on self-
eported illness in old age.
Methods
Data Source
In the Whitehall Study, 19029 men, most
aged 40 to 69 years, were examined between
1967 and 1970 to identify cardiorespiratory
disease and its risk factors.13 Participants com-
pleted a questionnaire concerning their jobs,
their personal and family medical histories,
and their smoking habits. Approximately two
thirds of the respondents were also asked about
car ownership and physical activity related to
work, and one third were asked about leisure
activity in general. A clinical examination in-
cluded height and weight, blood pressure, elec-
trocardiogram, and a blood sample analyzed
for cholesterol and blood sugar. Participants
were registered with the National Health Ser-
vice Central Register for mortality notification
(99% were successfully located).
Resurvey
The resurvey took place in 1997–1998
after a successful pilot study of 400 survivors
in XXXXXXXXXXThe National Health Service Cen-
tral Register identified the health authority in
which the cohort member was registered with
a family doctor. Chief executives of the rele-
vant health authorities granted permission to
the register to provide addresses of survivors
(or, failing this, to forward mail to them). In-
vitation letters, consent forms, and question-
naires were sent to individuals, along with up
to 2 reminders. A short version of the ques-
tionnaire covering priority information was sent
with the second reminder. The resurvey ques-
tionnaire included questions on socioeconomic
status (SES) and retirement, diseases diagnosed
Do Socioeconomic Disadvantages Persist
Into Old Age? Self-Reported Mo
idity in
a 29-Year Follow-Up of the Whitehall
Study
Fe
uary 2001, Vol. 91, No. 2278 American Journal of Public Health
TABLE 1—Resurvey Responses by Selected Characteristics: Whitehall Study, 1997–1998
Total No. Invited Completed Full Completed Short
to Take Part Questionnaire, No. (%) Questionnaire, No. (%) χ2 P
Age at resurvey, y
XXXXXXXXXX262 (9)
75– XXXXXXXXXX272 (9)
≥ XXXXXXXXXX339 (13) < .001
Baseline employment grade
High XXXXXXXXXX)
Middle XXXXXXXXXX (10)
Low XXXXXXXXXX16) < .001
Baseline smoking status
Never XXXXXXXXXX (9)
Ex-smoker XXXXXXXXXX (9)
Pipe/cigar smoker XXXXXXXXXX)
Cigarette smoker XXXXXXXXXX (12) < .001
Baseline evidence of cardiovascular disease
Yes XXXXXXXXXX11)
No XXXXXXXXXX XXXXXXXXXX
Baseline respiratory symptoms
No phlegm XXXXXXXXXX (10)
Persistent cough/phlegm XXXXXXXXXX10)
Increasing cough/phlegm XXXXXXXXXX)
Hospital admission in past XXXXXXXXXX) .018
Total XXXXXXXXXX (10)
y a doctor, and ability to ca
y out everyday
activities.
Outcome Measures
We used 4 measures of self-reported
mo
idity: general poor health, poor mental
health, poor physical performance, and dis-
ability. Those rating their health as poor o
very poor on a 5-point scale ranging from
very good to very poor were classified as
eing in poor general health. Poor mental
health was defined as a score below 60% of
the maximum on the 5-item mental health
section of the Short Form 36 Health Survey
(SF XXXXXXXXXXPoor physical performance was de-
fined as a score below 40% of the maximum
on the 10-item physical performance section
of the SF-36, which asks people to state
whether their health limits their activity ex-
tensively, a little, or not at all. Finally, dis-
ability was classified as an inability to engage
in at least 1 of 5 instrumental activities of daily
living (cooking a hot meal, cutting toenails,
dressing oneself, doing light housework and
simple repairs, and going up and down stairs
and steps).
Data on mental health, physical perform-
ance, and disability were available only for those
who completed the full questionnaire.The SF-
36 indexes were scored as recommended.16As
a result of missing data, 4% of those complet-
ing the full questionnaire were not assigned a
mental health score, 3% were not assigned a
physical performance score, and fewer than 1%
were excluded from the disability analyses.
Socioeconomic and Risk Facto
Measures
The main baseline socioeconomic clas-
sification used was employment grade (high,
middle, or low). High grades comprised sen-
ior managers and administrators; middle grades
comprised executives and professionals (e.g.,
economists, statisticians, and scientists) in less
senior positions; and low grades included cler-
ical staff, printing room officers, security of-
ficers, messengers, and catering staff.
Other socioeconomic indicators were ca
ownership and, measured retrospectively at the
esurvey, housing tenure at baseline (owner vs
enter). These variables were found to be clea
discriminators of mortality rates among olde
people in the United Kingdom in the 1970s,1
were incorporated in the Townsend index of
deprivation,17 and have subsequently been used
as socioeconomic indicators.5,18
Respondents were considered to have
preexisting cardiovascular disease if they had
at least 1 of the following at baseline: an ab-
normal electrocardiogram; self-reported
symptoms of angina, claudication, or poten-
tial myocardial infarction19; medication fo
high blood pressure; or a hospital admission
for a heart condition. We adjusted for car-
diorespiratory disease clinical risk factors that
existed at baseline because these risk factors
are associated with later disability20–22 and
can lead to more general problems in func-
tioning and health. The variables used in the
analyses were as follows: being in the top
quintile in terms of systolic or diastolic blood
pressure or total cholesterol level (assessed
with the entire 1960s cohort), body mass
index of 30 kg/m2 or greater, blood sugar level
above 96 mg/dL, persistent or increasing du-
ation of cough or phlegm or hospital admis-
sions for respiratory disease, and 4 or more
hospital admissions for other reasons.
Statistical Analysis
Chi-squaretestsforheterogeneitywereused
todetermineunivariateassociations.Logistic re-
gression(Stata5forWindows3.123)wasused to
estimateoddsratios (ORs)and95%confidence
intervals (CIs) foreachoutcome.Allmodels in-
cluded adjustment for age at resurvey (younge
than 75 years, 75–79 years, 80 years or older).
Results
Atthe timeof theresurvey, therewere8537
men from the original screening who, accord-
ing to National Health Service Central Registe
ecords, were alive and living in Great Britain.
Of these individuals, 6168 completed a full
questionnaire (72%)and873ashortone (10%),
209 of the latter by telephone. Seven percent of
espondents had been in high employment
grades at the initial screening, 12% had been in
lowgrades, and81%hadbeen inmiddlegrades.
The median age of respondents at the resurvey
was 77 years (range: 67–97), and the median
follow-up interval was 29 years (range: 26–31).
Response rates were lowest among men in
low employment grades, older men, smokers,
Fe
uary 2001, Vol. 91, No. 2 American Journal of Public Health 279
TABLE 2—Distribution (%) of Characteristics of Resurvey Respondents, by
Employment Grade at Baseline: Whitehall Study, 1997–1998
Employment Grade at Baseline, %
High Middle Low
(n=466) (n=5708) (n=866) �2 P
Resurvey
Age, y
XXXXXXXXXX
75– XXXXXXXXXX
≥ XXXXXXXXXX < .001
Net income<$ XXXXXXXXXX < .001
Had risen 1 grade category XXXXXXXXXX < .001
Had paid job after leaving Civil Service XXXXXXXXXX < .001
Cardiovascular disease
Angina XXXXXXXXXX
Heart attack XXXXXXXXXX
Stroke XXXXXXXXXX
Baseline
Cardiovascular disease XXXXXXXXXX
Top quintile
Systolic blood pressure XXXXXXXXXX < .001
Diastolic blood pressure XXXXXXXXXX
Total cholesterola XXXXXXXXXX