Epidemiological transitions in Pacific Island countries and territories: 1950-2023

Abstract Background: Whether Pacific Island life expectancy reflects a population's progress through the longevity transition or the period in which it occurred has not previously been distinguished. Existing evidence is fragmented, focusing on selected countries, age groups, diseases, or risks, or on broader analyses that omit most Pacific populations. Using a life-course framework and Global Burden of Disease (GBD) Study data spanning 1950–2023, we provide the first comparison of the epidemiological transition across all 18 Pacific Island countries and territories (PICTs), distinguishing position from timing effects. Methods: We used GBD 2023 estimates for 18 PICTs. We modelled annual life-expectancy change as a function of baseline life expectancy and calendar time, benchmarking Pacific trajectories against global patterns with and without Socio-demographic Index (SDI) adjustment, and against longevity-transition stage and period. We examined sex differentials and age- and cause-specific contributions to life-expectancy change across countries, subregions, and Oceania; derived mortality concentration ratios; compared leading causes and risks between 1990 and 2023; and partitioned potential lifespan into healthy, mortality-loss, and morbidity-loss components. Findings: Life expectancy in Oceania rose from 52·8 to 69·1 years (1950–2023), but improvement was 0·137 years per year slower than in global comparators after SDI adjustment (95% CI −0·205 to −0·070), with all 18 PICTs below the global benchmark and Nauru, the Solomon Islands, Tuvalu, and the Marshall Islands furthest below. Longevity transition stage (P=0·031) and historical period (P