How have changes in death by cause and age group contributed to the recent stalling of life expectancy gains in Scotland? Comparative decomposition analysis of mortality data, 2000-02 to 2015-17

Background Annual gains in life expectancy in Scotland were slower in recent years than in the previous two decades. This analysis investigates how deaths in different age groups and from different causes have contributed to annual average change in life expectancy across two time periods: 2000-02 to 2012-14 and 2012-14 to 2015-17. Methods Life expectancy at birth was calculated from death and population counts, disaggregated by five-year age-group and by underlying cause of death. Arriaga’s method of life expectancy decomposition was applied to produce estimates of the contribution of different age-groups and underlying causes to changes in life expectancy at birth for the two periods. Findings Average annual life expectancy gains between 2012-14 to 2015-17 were markedly smaller than in the earlier period. Almost all age-groups saw worsening mortality trends, which deteriorated for most cause of death groups between 2012-14 and 2015-17. In particular, the previously observed substantial life expectancy gains due to reductions in mortality from circulatory causes, which most benefited those aged 55-84 years, more than halved. Mortality rates for those aged 30-54 years and 90+ years worsened, due in large part to increases in drug-related deaths, and dementia and Alzheimer’s disease respectively. Interpretation Future research should seek to explain the changes in mortality trends for all age-groups and causes. More investigation is required to establish to what extent shortcomings in the social security system and public services may be contributing to the adverse trends and preventing mitigation of the impact of other contributing factors, such as influenza outbreaks.