Causes of death contributions to the sex gaps in life expectancy: evidence by education levels from Australia

Background
In all high-income countries, including Australia, females have a longer life expectancy than males. The sex gap in life expectancy has been shown to vary according to highest level of education, a measure of socioeconomic position, with a smaller gap among those with higher education. However, the cause contributions to education-related differences in the sex gap in life expectancy remain unclear but may provide insights into the underlying drivers of these inequalities.

Methods
Using Australian data from the 2016 Census of Population and Housing linked to Death Registrations (2016–2019), we quantified the age- and cause-specific contributions to the sex gap in life expectancy in relation to highest attained level of education: university, secondary/post-secondary, and lower than secondary. Date and cause of death information were obtained from Death Registrations using underlying cause and grouped into broad causes of death.

Results
At age 25, the sex gap in life expectancy was 3.79 (3.69, 3.88) years in the total population, and ranged from 2.28 (1.99, 2.56) years among those with a university degree to 4.67 (4.46, 4.89) years among those with lower than secondary education. Across all education groups, the largest contributors to the sex gap in life expectancy were cardiovascular diseases, cancers, and external causes, together accounting for 70–80% of the gap. Although absolute cause of death contributions among those with a university education were smaller when compared to those with lower levels of education, relative contributions from cardiovascular diseases and non-lung cancers were larger among the university educated population. Age-specific contributions were concentrated at older ages for those with a university degree compared to those with lower levels of education (assessed with the interquartile range).

Conclusion
Our study reveals that deaths from cardiovascular diseases, cancers and external causes of death make the largest contributions to the sex gap in life expectancy in Australia. Public health actions targeting these causes, particularly if directed towards preventing deaths among men with lower levels of education, are likely to reduce the sex gap in life expectancy, with potential for larger absolute gains in life expectancy among men with lower levels of education.