Educational inequality in cancer mortality: a record linkage study of over 35 million Italians

Large studies are needed to evaluate socioeconomic inequality for site-specific cancer mortality. We conducted a longitudinal census-based national study to quantify the relative inequality in cancer mortality among educational levels in Italy. We linked the 2011 Italian census with the 2012 and 2013 death registries. Educational inequality in overall cancer and site-specific cancer mortality were evaluated by computing the mortality rate ratio (MRR). A total of 35,708,445 subjects aged 30-74 years and 147,981 cancer deaths were registered. Compared to the lowest level of education (none or primary school), the MRR for all cancers in the highest level (university) was 0.57 (95% CI 0.55; 0.58) in men and 0.84 (95% CI 0.81; 0.87) in women. Higher education was associated with reduced risk of mortality from lip, oral cavity, pharynx, oesophagus, stomach, colon and liver in both sexes. Higher education (university) was associated with decreased risk of lung cancer in men (MRR: 0.43, 95% CI 0.41; 0.46), but not in women (MRR: 1.00, 95% CI 0.92; 1.10). Highly educated women had a reduced risk of mortality from cervical cancer than lower educated women (MRR: 0.39, 95% CI 0.27; 0.56), but they had a similar risk for breast cancer (MRR: 1.01, 95% CI 0.94; 1.09). Education is inversely associated with total cancer mortality, and the association was stronger in men. Different patterns and trends in tobacco smoking in men and women account for at least most of the gender differences.