Mesothelioma mortality in Great Britain: how much longer will dockyards dominate?

We aimed to investigate whether there has been a geographic shift in the distribution of mesothelioma deaths in Great Britain given the decline of shipbuilding and progressive exposure regulation.

We calculated age-adjusted mesothelioma mortality rates and estimated rate ratios for areas with and without a dockyard. We compared spatial autocorrelation statistics (Moran's I) for age-adjusted rates at local authority district level for 2002-2008 and 2009-2015. We measured the mean distance of the deceased's postcode to the nearest dockyard at district level and calculated the association of average distance to dockyard and district mesothelioma mortality using simple linear regression for men, for 2002-2008 and 2009-2015.

District age-adjusted male mortality rates fell during 2002-2015 for 80 of 348 districts (23%), rose for 267 (77%) and were unchanged for one district; having one or more dockyards in a district was associated with rates falling (OR=2.43, 95% CI 1.22 to 4.82, p=0.02). The mortality rate ratio for men in districts with a dockyard, compared with those without a dockyard was 1.41 (95% CI 1.35 to 1.48, p<0.05) for 2002-2008 and 1.18 (95% CI 1.13 to 1.23, p<0.05) for 2009-2015. Spatial autocorrelation (measured by Moran's I) decreased from 0.317 (95% CI 0.316 to 0.319, p=0.001) to 0.312 (95% CI 0.310 to 0.314, p=0.001) for men and the coefficient of the association between distance to dockyard and district level age-adjusted male mortality (per million population) from -0.16 (95% CI -0.21 to -0.10, p<0.01) to -0.13 (95% CI -0.18 to -0.07, p<0.01) for men, when comparing 2002-2008 with 2009-2015.

For most districts age-adjusted mesothelioma mortality rates increased through 2002-2015 but the relative contribution from districts with a dockyard fell. Dockyards remain strongly spatially associated with mesothelioma mortality but the strength of this association appears to be falling and mesothelioma deaths are becoming more dispersed.