Background The most likely underlying causes of the higher mortality in Scotland compared to England & Wales (E&W) and in Glasgow compared to Liverpool and Manchester have been identified recently as relating in large part to vulnerabilities created by adverse historical living conditions allied to detrimental political decision-making. However, it was also suggested that there is a protective effect in E&W and Manchester of greater ethnic diversity, given the latter’s association with lower-than-expected mortality among UK populations. We sought to assess the extent to which Scotland’s ‘excess’ mortality (i.e. beyond that explained by deprivation) was attenuated by adjusting for ethnic diversity.

Methods The Scottish Longitudinal Study (SLS) and the ONS Longitudinal Study of E&W were used. E-dataSHIELD methodology was applied to analyse the restricted access data. Risk of all-cause mortality (2001–2010) was compared between 35–74 year-old residents of Scotland and E&W, and between Glasgow and Manchester, using Poisson regression. Models adjusted for age, gender, socio-economic position (SEP) and an ethnicity*country of birth (CoB) interaction. CoB has been shown to be important in explaining differences in ethnic mortality related to the ‘healthy migrant effect’.

Results 18% of the Manchester sample was classed as non-White compared to only 3% in Glasgow. The equivalent figures for E&W and Scotland were 10.4% and 1.2% respectively. The mortality Incident Rate Ratio (IRR) was 1.33 (95% CIs 1.13, 1.56) in Glasgow compared to Manchester. This reduced to 1.25 (95% CI 1.07 to 1.47) after adjustment for SEP, and further reduced to 1.20 (95% CI 1.02 to 1.42) after adjustment for ethnicity*CoB. The equivalent figures for Scotland compared to E&W were: 1.18 (95% CIs 1.16 to 1.21) overall, reduced to 1.08 (95% CIs 1.05 to 1.10) after adjustment for SEP, and then to 1.04 (95% CIs 1.02 to 1.07) after adjustment for ethnicity*CoB. Across all samples, Non-Whites born outside UK/ROI had a lower risk of mortality than Whites born in UK/ROI; however, among the Scottish samples only, non-Whites born in UK/ROI had a higher risk of mortality compared with Whites born in UK/ROI – IRR 1.77 (95% CIs 1.10 to 2.85) for Scotland, 3.10 (95% CIs 1.28 to 7.51) for Glasgow.

Conclusion The research supports the hypothesis that greater diversity in ethnicity and migration status plays a partial role in explaining Scottish excess mortality. In Glasgow’s case, however, a large excess remains: thus previously articulated policy implications such as addressing poverty, vulnerability and inequality still apply. Further research is warranted into the relatively high mortality of non-Whites born in UK/ROI and resident in Scotland.