Investigators from Sweden and France studied the association between alcohol abuse and the risk of pancreatic cancer.
The risk of pancreatic cancer was analyzed among patients admitted to hospital from 1965 to 1994. Data was obtained from the Swedish Inpatient Register.
Patients were admitted to hospital for alcoholism (n = 178,688), alcoholic chronic pancreatitis (n = 3500), non-alcoholic chronic pancreatitis (n = 4952), alcoholic liver cirrhosis (n = 13,553), or non-alcoholic liver cirrhosis (n = 7057).
The patients were followed up through to 1995, by linkage to nationwide registers.
Standardized incidence ratios (SIRs) were calculated by taking the general Swedish population as reference.
To minimize the possible influence of selection bias, the authors excluded the first year observations.
Alcoholics had only a modest, 40%, excess risk of pancreatic cancer (SIR 1.4).
| Alcoholics had 40% excess risk of pancreatic cancer.
However, smokers were over-represented among alcoholics. Thus, the true SIR among alcoholics may have been the same as the general population, and could have been confounded by smoking.
SIR among alcoholic chronic pancreatitis patients (2.2) was considerably lower than that among non-alcoholic chronic pancreatitis patients (8.7). It also decreased with increasing duration of follow up in both groups, indicating that most of the excess risk might be explained by reversed causation from undiagnosed cancers.
The researchers found that, among patients with alcoholic liver cirrhosis, the increased risk of pancreatic cancer was also moderate (SIR 1.9).
However, no significant excess risk was found among non-alcoholic liver cirrhosis patients (SIR 1.2).
Dr W. Ye, of the Karolinska Institutet, Stockholm, Sweden, concluded on behalf of fellow authors, "The excess risk for pancreatic cancer among alcoholics is small and could conceivably be attributed to confounding by smoking."