Deprivation and mortality in Glasgow: changes from 1980 to 1992
BMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6967.1481 (Published 03 December 1994) Cite this as: BMJ 1994;309:1481
- Peter G McCarron, registrar in public health medicinea,
- George Davey Smith, senior lecturer in epidemiology and public healthb,
- John J Womersley, consultant in public health medicinea
- a Department of Public Health, Greater Glasgow Health, Glasgow G1 1ET
- b University of Glasgow, Department of Public Health, University of Glasgow, Glasgow G12 8RZ
- Correspondence to: Dr Davey Smith.
- Accepted 23 August 1994
Social class differentials in mortality in Britain increased between the early 1970s and early 1980s,1 and various indicators of increasing social polarisation since 1980 suggest that these mortality differentials will have widened further.2 Further widening is supported by analyses of area based mortality in the north of England which show that the differences in mortality between the most deprived and most affluent areas increased greatly between 1981 and 1991.3 Preliminary analyses from Glasgow showed a similar picture.4 We report the trends in socioeconomic mortality differentials in Greater Glasgow from 1980 to 1992.
Methods and results
Numbers of deaths by sex and 10 year age band were available for 1980-82 and 1990-92 for people aged 15-64 residing in the area covered by the Greater Glasgow Health Board. Using the 1981 and 1991 census populations for Greater Glasgow as denominators we calculated standardised mortality ratios and confidence intervals. The standardised mortality ratio for the whole of Glasgow in 1980-82 was taken as 100.
We assigned postcode sectors in Greater Glasgow to eight categories (neighbourhood types4) on the basis of a cluster analysis of 30 area based sociodemographic variables from the 1981 census. The categories ranged from NT1 (most affluent) to NT8 (most deprived). The same neighbourhood type categories were used for 1980-82 and 1990-92. The variables used to assign neighbourhood type included all those used in the Carstairs deprivation index5 and other variables that allow better discrimination within deprived areas. The high overall levels of deprivation in Glasgow result in other indices consigning large proportions of the population to the lowest categories, thus reducing their discriminatory power.
We combined NT1 and NT2 to produce the affluent areas—those with high owner occupation levels, high rates of single and multiple car ownership, and a high proportion of professionals and non-manual workers. NT7 and NT8 were combined to produce the deprived areas—those with high local authority accommodation, high unemployment rates, and mainly unskilled occupations among those working. The percentage of the population of Greater Glasgow aged 15-64 living in the affluent areas was 21.8% in 1981 and 25.2% in 1991. The percentage living in deprived areas was 26.4% in 1981 and 23.6% in 1991.
The standardised mortality ratios were considerably higher for the deprived than affluent areas for both sexes, for the two age bands analysed, and for both periods (table). The ratios of standardised mortality ratios between the deprived and affluent areas increased substantially between 1980-82 and 1990-92 for both sexes and for all age groups. As a common standard was used for the two periods the change in standardised mortality ratio over time reflects change in mortality over the 10 years. For men aged 15-44 in the deprived areas mortality increased by 9% (95% confidence interval -4% to 26%). For 15-64 year olds in affluent areas mortality fell substantially: by 18% (10% to 26%) for men and 22% (11% to 30%) for women. Considerably smaller falls were seen in the deprived areas: 4% (2% to 10%) for men and 4% (-5% to 11%) for women.
Standardised mortality ratios (95% confidence intervals) in least and most deprived areas of GreaterGlasgow, 1980-82 and 1990-92*
Analyses (not shown) of deaths during 1985-87 with means of 1981 and 1991 census data as denominators show that the wider mortality differentials in 1990-92 compared with 1980-82 are part of a continuing trend over the decade which is showing no signs of decreasing.
Comment
In Glasgow, as in the north of England,3 socioeconomic mortality differentials have recently increased. Populations in deprived areas have experienced only small falls in mortality, and mortality may have increased in young men and older women. In affluent areas, however, mortality has decreased steadily. The increasing differences in mortality coincide with sharp increases in inequalities in income.2 The challenge remains to determine whether directly addressing material inequalities through broad social policy could ameliorate this unacceptable iniquity.