Cause of death contributions to life expectancy disparity in Fiji between Indigenous iTaukei and Fijians of Indian descent: a retrospective observational analysis of national mortality data from 2018 to 2023

Ethnic disparities in life expectancy (LE) have long been recognised in Fiji. This study quantifies cause-specific mortality contributions to LE disparities between Indigenous iTaukei and Fijians of Indian descent (FID) during 2018–2023. A retrospective observational analysis was conducted using unit-record mortality data ( n = 49,941) recorded in the Fiji national mortality database. LE and cause-specific mortality rates were calculated by sex, ethnicity, and age group. LE differences between iTaukei and FID were decomposed by age and cause of death. During 2018–2023, annual LE was approximately one year lower in iTaukei males (range 64–66 years) than FID males (65–67 years), and four-to-five years lower in iTaukei females (66–68 years) than FID females (71–73 years), with the ethnic gap widening to 2.6 years (males) and 5.6 years (females) in 2021 due to excess COVID-19 mortality among iTaukei. The main cause-specific contributions to the LE disparity were from higher mortality in iTaukei than FID from cardiovascular disease (CVD) (381 vs. 371 per 100,000 in males; 311 vs. 199 in females), cancer (91 vs. 49 per 100,000 in males; 153 vs. 73 in females), and infectious disease (60 vs. 32 per 100,000 in males; 58 vs. 36 in females). These differences contributed − 0.12 years (CVD), − 0.52 years (cancer), and − 0.49 years (infection) to lower iTaukei LE in males, and − 1.88 years (CVD), − 1.41 years (cancer), and − 0.46 years (infection) in females. COVID-19 mortality in 2021 was substantially higher in iTaukei than FID (140 vs. 45 per 100,000 in males; 108 vs. 43 in females), reducing iTaukei LE by a further 1.0 year in both sexes. Higher external-cause mortality in FID (75 vs. 47 per 100,000 in males; 41 vs. 20 in females) partially offset LE gaps. iTaukei experienced persistently lower LE than FID throughout 2018–2023, especially among females, and during the COVID-19 pandemic. Excess mortality from CVD, cancer, and infection, particularly the excess cancer burden in young adult iTaukei women, requires targeted prevention and treatment interventions. Similarly, elevated external-cause mortality in young FID adults warrants focused investigation and improved surveillance.