Socio-demographic and regional patterns in esophageal and gastric cancer mortality in Sweden

Rickard Ljung, Karolinska Institutet
Sven Drefahl, Stockholm University
Gunnar Andersson, Stockholm University
Jesper Lagergren, Karolinska Institutet

Background: Socio-demographic factors and area of residence might influence the development of esophageal and gastric cancer, but there is a need for research of population-based design and large sample size. Methods: Register-based nationwide cohort study. All residents in Sweden aged 30 to 84 years, in 1990 to 2007 were followed up until 2007 for esophageal and gastric cancer mortality. In total, the study generated 15.2 million person-years in men and 15.8 million person-years in women. Place of birth, place of residence, educational level and marital status were accounted for in the analyses. Cox regression yielded hazard ratios (HR) with 95 % confidence intervals (CI). Results: In men, 3,789 deaths from esophageal cancer and 7,607 deaths from gastric cancer occurred during follow-up, and for women the corresponding numbers were 1,337 and 4,631. Being born in a city region increased the risk of death from esophageal cancer in both men and women compared to the reference group of those living in a non-city region in central and southern Sweden (HR= 1.33, and HR= 1.15, respectively). Death from gastric cancer was increased for those born in Northern parts of Sweden compared to the reference group (HR=1.34 in men and HR=1.27 in women). There was a strong inverse educational gradient in men and women, those with 15 or more years of education had around 50% lower risk of death from both cancers compared to those with 9 years. Being married was protective for risk of death from both cancers, however, excess mortality was much higher for esophageal cancer. Conclusion: Being born and living in large city areas is a risk factor for esophageal cancer mortality, while a higher risk of gastric cancer mortality was identified among those born in rural areas. Low educational level and living alone are risk factors for both these tumors.