Mortality by income in the elderly population in Italy: new evidence from an innovative microdata integration

BACKGROUND: Socioeconomic inequalities in mortality persist across welfare systems. Income, a key determinant of material resources and long-term security, is rarely measured at the individual level in epidemiological studies due to data limitations. This study addresses this gap by combining individual-level income and mortality data in Italy, focusing on the elderly, for whom income may be a more sensitive socioeconomic indicator than education. METHODS: A nationwide retrospective cohort study was conducted on residents aged ≥65 years (n=12.8 million), as of 31 December 2018. Individual income for 2018 was obtained from administrative tax and social security data and integrated with 2019 mortality using national population registers. Mortality Rate Ratios (MRRs) with 95% CIs were estimated using negative binomial regression models, both age-adjusted and fully adjusted for marital status, education and geographic area. Analyses were stratified by sex. RESULTS: A clear income gradient in mortality was observed. Excess mortality gradually decreased across ascending income groups. In fully adjusted models, individuals in the lowest income class had significantly higher mortality than those in the highest (MRR=1.65, 95% CI 1.61 to 1.70 in men; MRR=1.47, 95% CI 1.43 to 1.50 in women). Education and marital status also influenced mortality, while geographic differences were minimal. CONCLUSIONS: In Italy, substantial income-related inequalities in mortality persist among the older population, showing that socioeconomic disparities remain marked even with broad access to healthcare. Individual-level income is a key predictor of mortality and should be prioritised in addressing health inequalities in ageing societies, as it better reflects material conditions relevant to health than educational attainment.