Differences in education and premature mortality: a record linkage study of over 35 million Italians

Large, representative studies are needed to evaluate cause-specific aspects of socio-economic inequalities in mortality. We conducted a census-based retrospective cohort study to quantify differences in cause-specific premature mortality by educational level in Italy. We linked the 2011 Italian census with 2012 and 2013 death registries. We used the mortality rate ratio (MRR) as a measure of relative inequality. Overall, 305 043 deaths (190 061 men-114 982 women) were registered from a population of 35 708 445 subjects aged 30-74. The age-standardized mortality rate for all educational levels was 57.68 deaths per 10 000 person-years among men and 31.41 among women. MRR from all causes was 0.51 (95% CI: 0.49; 0.52) in men and 0.63 (95% CI: 0.61; 0.65) in women for the highest (university) compared to the lowest level of education (none or primary school). The association was stronger in single than in married individuals: MRRs were 0.36 (95% CI: 0.34; 0.39) in single men, 0.57 (95% CI: 0.55; 0.59) in married men, 0.44 (95% CI: 0.40; 0.47) in single women and 0.69 (95% CI: 0.66; 0.72) in married women. High education was associated with lower mortality from liver, circulatory, chronic respiratory and genitourinary diseases in both sexes. Highly educated men had a lower mortality from lung cancer than less educated men, whereas highly educated women did not have a reduced mortality from lung and breast cancers. Level of education is a strong indicator of premature mortality. The magnitude of the association between educational level and mortality differs across sexes, marital status and causes of death.