Shipyards and sectarianism: how do mortality and deprivation compare in Glasgow and Belfast?

The extent to which the higher level of mortality seen in Glasgow compared with other UK cities is solely attributable to socio-economic deprivation has been the focus of much discussion recently. Some authors have suggested that poorer health in the city may be influenced by issues related to its history of religious sectarianism. In order to investigate this further, this study compared deprivation and mortality between Glasgow and Belfast, a similar post-industrial city, but one with a considerably more pronounced sectarian divide.

To compare the deprivation and mortality profiles of the two cities; to assess the extent to which any differences in mortality can be explained by differences in area-based measures of deprivation; and to examine whether these analyses shed any light on the 'sectarianism' hypothesis for Glasgow's excess mortality relative to elsewhere in the UK.

Replicating the methodology of a recent study comparing deprivation and mortality in Glasgow, Liverpool and Manchester, rates of 'income deprivation' for 2005 were calculated for every small area across the two cities (average population size: 1810 in Belfast; 1650 in Glasgow). Standardized mortality ratios were calculated for the period 2003-2007 for Glasgow relative to Belfast, standardizing for age, gender and income deprivation decile.

While total levels of deprivation were slightly higher in Glasgow than in Belfast (24.8% of Glasgow's population were income deprived in 2005 compared with 22.4% in Belfast), Belfast was more unequal in terms of its distribution of deprivation across the city. After standardizing for age, sex and deprivation, all-cause mortality in Glasgow was 27% higher for deaths under 65 years of age and 18% higher for deaths at all ages. Higher all-cause mortality in Glasgow was shown in the majority of sub-analyses (i.e. for most age groups, both sexes and across the majority of deprivation deciles). Analyses of particular causes of death showed significantly higher mortality in Glasgow relative to Belfast for all conditions examined except 'external causes'. Notably higher mortality was evident for drug-related poisonings and alcohol-related causes among men in both cities. With a small number of exceptions, the results were very similar to those shown for Glasgow in comparison with Liverpool and Manchester.

Area-based deprivation did not explain the higher mortality in Glasgow in comparison with Belfast. Belfast has a more profound history of sectarianism, and similar climatic conditions, to Glasgow. If these factors were to be important in explaining the high mortality in Glasgow, the question arises as to why they have not produced similar effects in Belfast.