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
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