The objective of this study is to ascertain whether income inequality and per capita income of area of residence show a relationship with mortality in Spain. Data are from a nation-wide prospective study with a 7-year mortality follow-up covering all persons living in Spain's 50 provinces in 2001. In total 28,944,854 subjects aged 25 years or over at baseline were studied. Rate ratio for total mortality and cause-specific mortality, according to provincial income inequality and per capita income in two age groups, 25-64 years (adult population) and 65 years and over (elderly population). Provincial income inequality was not related to total mortality or cause-specific mortality. Total mortality rate ratios among residents of the poorest versus the richest provinces were 0.89 (95% CI 0.95-0.93) in men and 0.91 (0.87-0.96) in women, among the adult population; and 1.02 (0.97-1.08) in men and 1.08 (1.02-1.16) in women, among the elderly population. With the exception of cardiovascular-disease mortality for which no association with per capita income was observed, adult residents of the poorest provinces registered the lowest mortality rate ratio for other causes of death. Elderly residents of the poorest provinces registered the highest mortality rate ratio for cardiovascular disease and the lowest mortality rate ratio for cancer and external causes. Aside from cardiovascular-disease mortality, the lowest mortality for most causes of death was registered by residents of the poorest provinces. Nevertheless, these findings need to be confirmed by similar studies using smaller areas as the unit of analysis.
Keywords: Income inequality; Leading causes of death; Mortality; Multilevel study; National prospective study; Per capita income; Spain.