Census records linked to death registrations followed 54,529 adults in same-sex relationships and 7.9 million in different-sex relationships from 2011 to 2023, weighted to balance age, education and household income. All-cause mortality was about a quarter higher for both women (HR 1.25) and men (HR 1.24) in same-sex relationships, and external-cause mortality was higher still (HR 2.56 and 1.96). The external-cause gap among women narrowed from HR 3.40 before the 2017 legalisation of same-sex marriage to 2.04 after, but remained elevated in both periods.
Why it is interesting: A whole-population mortality estimate for a group that most national statistics cannot identify, available only through census-to-death linkage and resting on relationship status as the proxy.