PANCREATIC-CANCER AND ABO BLOOD-TYPE - A CASE-CONTROL STUDY

BACKGROUND: A hospital based case-control study (controls were matched to cases by age, sex and hospital) has been carried out to analyze the relation between pancreatic cancer and blood type. METHODS: This study is based on data collected by the Boston Collaborative Drug Surveillance Programme. This large hospital-based study has been collecting hospital admissions occurred in six different countries. To estimate relative risk (RR) associated with blood type, odds ratios were calculated by multiple logistic regression using conditional maximum likelihood estimation based on the matching factors (age, sex and hospital). The final analysis is based in 108 matched sets (108 cases and 374 controls). RESULTS: The results indicate a modest excess risk among persons with blood type A (RR = 1.52, 95 % confidence interval: 0.87 - 2.67). Smoking was also a positive predictor of disease. CONCLUSIONS: In accordance with previous reports, this study shows some evidence of a positive association between blood type A and risk of pancreatic cancer.