Esophageal cancer risk among immigrants in Sweden

Esophageal squamous cell carcinoma is linked to alcohol drinking, whereas esophageal adenocarcinoma risk is increased by overweight and obesity. Both histologies are directly related to tobacco smoking. We wanted to define the risk of esophageal cancer by histology and length of stay among immigrants in Sweden. The nationwide Swedish Family Cancer database (2010 version: data on cancers originate from the nationwide Swedish Cancer Registry) was used to calculate standardized incidence ratios (SIRs) for esophageal cancer among immigrants compared with the native Swedes. SIRs for lung cancer were also calculated as a proxy for smoking prevalence. The patient series covered 5930 male and 1998 female Swedes, and 410 and 198 immigrants. The risk of esophageal cancer was increased in female Finns (SIR=1.66), Britons (3.73), and Southeast Africans (5.26), whereas male Baltic (0.44), former Yugoslavian (0.47), other Europeans (0.58), and other Asians (0.52) showed a decreased risk. The risk of squamous cell carcinoma was increased among Finns (men=1.32, women=1.90) and Iranian women (3.80), whereas Danish men (1.66) had an increased risk of adenocarcinoma. No trend was observed for the risks in immigrants according to the length of stay. We found no covariation between the birth region-specific SIRs for squamous cell carcinoma and lung cancer. Early childhood exposures or preservation of original habits might be the main environmental exposures influencing squamous cell carcinoma risks in some immigrants. The increased risk of adenocarcinoma among Danish men may confirm the role of obesity in adenocarcinoma risk.