Socioeconomic inequalities in mortality: Men aged 25-64 2001-3(4)

Chris White

Principal Research Officer

Office for National StatisticsLS Clearance 20105D

Introduction and context

• First official analysis of adult mortality by the final version of the National Statistics Socio-Economic Classification (NS-SEC), updating previous analysis by RGSC

• Sets benchmark for inequalities in premature death in early 21st Century to enable future monitoring and compare impacts of different social and occupational circumstances

• Intend to follow-up with further analyses covering:

– males and females of all ages

– patterns of inequalities in mortality by cause of death

– geographical area (GOR’s)

– independent influence of NS-SEC adjusting for other indicators of SES

Background

• Examinations of social inequalities in mortality generally used one of two analytical approaches:

–Unlinked records approach

•advantages include detailed breakdowns, precise estimates

•disadvantages include numerator-denominator and health selection bias

–linked records follow-up approach

•advantages include numerator-denominator correspondence and possibility to control selection

•disadvantages include small numbers constraining detailed breakdowns and limiting precision

Objectives

• Assess the presence of biases through complementary linked record analyses

• Adjust unlinked records estimates to optimise validity of decennial results

• Measure remaining dissonance in estimates and examine potential influences

• Compare analyses of all-cause mortality in men aged 25-64 by NS-SEC 9 analytic classes for 2001-3, using unlinked records

• Assess conformity of the age standardised pattern by NS-SEC across the age range

National Statistics Socioeconomic Classification (1)

• Delineates SE structure by employment relations not occupational skill/perceived status

–Service relationship:

employee renders ‘service’ to employer in return for ‘compensation’

–Labour contract:

employee gives discrete amounts of labour in return for a wage calculated on amount of

work done or by time worked.

–Intermediate:

Forms of employment regulation that combine aspects of ‘service relationship’ and

‘labour contract’

• No manual / non-manual divide and greater within class homogeneity and between class heterogeneity than was present in RGSC classes

• Distribution between classes is more even than with RGSC

National Statistics Socioeconomic Classification (2)

Analytic classes

1.1 Large employers and higher managers

1.2 Higher professionals

2 Lower managerial and professional

3 Intermediate

4 Small employers and own account workers

5 Lower supervisory technical occupations

6 Semi-routine occupations

7 Routine occupations

8 Never Worked and Long-term unemployed

NS-SEC is derived from SOC 2000, employment status and size of organisation

Data Sources, study populations and data issues

• Death Occurrences 2001-03 and 2001 census, males aged 25-64 in England and Wales

• ONS Longitudinal Study sample enumerated in 2001, traced and followed between census day and 31st December 2004

• Coding of occupation at census

– Filter x

– Reduced NS-SEC

• Health selection – assigned NS-SEC90 class from LS members 1991 census record if assigned to an unoccupied NS-SEC in 2001

• Under-enumeration at census 2001 (MYPE 2001,2002, 2003)

Optimising cross-sectional denominator

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

1.1 1.2 2 3 4 5 6 7 Other

NS-SEC Analytic Classes

Unadjusted - Filter X rule present

Adjusted - Filter X & Selection

Count in '000 Source: Census 2001, MYPE 2001-3, ONS LSt - crown copyright

Assessing numerator conformity

• Imbalance in NS-SEC allocation at census and death

– Classes 1.1 and 2 had lower proportion assigned at census

– Class 3 and Never worked and Long-term Unemployed had higher proportion

– Other classes were within margin of sampling variation

• Examination of LS census and death records showed systematic misallocation of operational category L6

– occupations categorised as Intermediate distinguished by employment status

– All deaths (n=18) assigned to L6 occupations at census were assigned to L7 occupations at death due to difference in reporting of employment status

– age-specific adjustment factors generated and extrapolated to death occurrences for period 2001-03

– results in > in deaths allocated to class 2 ( 9 % ) and < in class 3 of ( 23 % )

Designation of deaths by source

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9

NS-SEC analytic class

PE

R C

EN

T

DO adjusted LS adjusted

Source: Death Occurrences 2001-03, ONS LS - Crown copyright

Age-standardised death rates per 100,000 PYRs by NS-SEC: men aged 25-64, England and Wales, death occurrences 2001-03

0

100

200

300

400

500

600

1.1 1.2 2 3 4 5 6 7

NS-SEC Analytic Classes

Unadjusted Adjusted

Sources: 2001 Census, MYPE 2001-3, Death occurrences 2001-3, ONS LS - crown copyright

Age-standardised death rates per 100,000 PYRs by NS-SEC: men aged 25-64, England and Wales, LS sample 2001-4

0

200

400

600

800

1000

1200

1.1 1.2 2 3 4 5 6 7 NW andLTU

NS-SEC Analytic Classes

RATE Source: ONS Longitudinal Study - crown copyright

Age-standardised death rates per 100,000 PYRs by occupied NS-SEC: men aged 25-64, England and Wales, cross-sectional sources 2001-3 and LS sample 2001-4

Sources: 2001 Census, MYPE 2001-3, Death occurrences 2001-3, ONS LS - crown copyright

0

100

200

300

400

500

600

1.1 1.2 2 3 4 5 6 7

NS-SEC Analytic Classes

cross-sectional LS sampleRATE

Age-specific rates per 100,000 by NS-SEC: England and Wales 2001-03

Sources: 2001 Census, MYPE 2001-3, Death occurrences 2001-3, ONS LS - crown copyright

0

200

400

600

800

1000

1200

1400

1600

1800

25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64

1.1 1.2 2 3

4 5 6 7

RATE

Summary of Findings (1)

• A clear social gradient in mortality risk for men aged 25-64 is present in contemporaneous linked and unlinked data sources (2.11 – 2.82)

–Good discrimination of mortality risk between employment relations domains

–Consistent pattern of decreasing mortality in each adjacent class from class 7 - 1.1 implying intensity of service relationship : labour contract continuum is relevant

–Mortality differences found within employment relations domains will be concealed in descriptions of inequalities using the most condensed version of NS-SEC

• The protective influence of class 4 reported in analyses for the period 1991-93 was not found in this analysis

• The Never worked and Long-term unemployed have clearly distinct life chances compared with men in occupied NS-SEC classes

• The pattern of age-standardised mortality by NS-SEC predominantly consistent across age range examined

Summary of Findings (2)

• Differences between sources

– Linked record method produces a higher rate in class 1.1 and lower rate in class 7

resulting in a shallower gradient, but class differences only statistically

significant in class 7

– May operate through differential exposure to long-term unemployed in NS-SEC

and its capture at census and death registration

– A lower national rate for England and Wales observed in LS sample compared

with aggregate data

– Unknown rate of unobserved embarkation and under-enumeration of younger

men in 2001 census may be drivers of differences

– Some allocations to class 3 at death suspect: adjustment for operational category

L6 advised in mortality analyses by NS-SEC

– Use of optimised populations recommended to adjust for known biases

Limitations of the research

• Restriction to men aged 25-64 will weaken mortality gradient:

– higher risk of death from accidental and violent causes found in low

socioeconomic status younger men

• Health-related social mobility not examined, but necessary:

– potential explanation for mortality gradient

• Independent influence of NS-SEC on mortality not examined:

– How does it stack up against alternative socioeconomic characteristics such

as tenure, area deprivation, educational attainment

Publication

• The article will be published in:

HEALTH STATISTICS QUARTERLY

NOVEMBER 2007 ISSUE

Social inequalities in adult male mortality by the National

Statistics Socio-Economic Classification: England and Wales

2001-2003