Socio-demographic diversity and unexplained variation in death rates among the most deprived parliamentary constituencies in Britain

Background
There is considerable unexplained variation in death rates between deprived areas of Britain. This analysis assesses the degree of variation in socio-demographic factors among deprivation deciles and how variables associated with deaths differ among the most deprived areas.

Methods
Death rates 1996–2001, Carstairs' 2001 deprivation score and indicators, population density, black and minority ethnic group (BME) and population change 1971–2001 were calculated for 641 parliamentary constituencies in Britain. Constituencies were grouped into Carstairs' deciles. We assessed standard errors of all variables by decile and the relationship between death rates and socio-demographic variables with Pearson's correlations and linear regression by decile and for all constituencies combined.

Results
Standard errors in death rates and most socio-demographic variables were greatest for the most deprived decile. Death rates among all constituencies were positively correlated with Carstairs' score and indicators, density and BME, but for the most deprived decile, there was no association with Carstairs and a negative correlation with overcrowding, density and BME. For the most deprived decile multivariate models containing population density, BME and change had substantially higher R².

Conclusions
Understanding variations in death rates between deprived areas requires greater consideration of their socio-demographic diversity including their population density, ethnicity and migration.