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This article analyzes the association between alcohol consumption and pancreatic cancer mortality in never smokers. The study examines the relationship by beverage type and tobacco smoking.
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Journal Club Alcohol, Other Drugs, and Health: Current Evidence March–April 2011
Featured Article Association of Alcohol Intake With Pancreatic Cancer Mortality in Never Smokers Gapstur SM, et al. Arch Intern Med. 2011;171(5):444–451.
Study Objective • To examine the relationship between alcohol consumption and pancreatic cancer and to assess whether the association varied by beverage type or as a result of tobacco smoking.
Study Design • Analysis of cancer mortality data from the Cancer Prevention Study II, a prospective study of 1,030,467 US adults aged ≥30 years followed from 1982–2006.
Assessing Validity of an Article About Harm • Are the results valid? • What are the results? • How can I apply the results to patient care?
Are the Results Valid? • Did the investigators demonstrate similarity in all known determinants of outcomes? Did they adjust for differences in the analysis? • Were exposed patients equally likely to be identified in the two groups? • Were the outcomes measured in the same way in the groups being compared? • Was follow-up sufficiently complete?
Did the investigators demonstrate similarity in all known determinants of outcomes? Did they adjust for differences in the analysis? • Yes. • Multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were computed using Cox proportional hazards regression analysis controlling for age, sex, race/ethnicity, education, marital status, body mass index, family history of pancreatic cancer, and personal history of gallstones, diabetes mellitus, or smoking.
Were exposed patients equally likely to be identified in the groups? • Yes. • All participants completed a baseline survey including the question, “How many cups, glasses, or drinks of these beverages do you usually drink a day, and for how many years?” Intake amounts of beer, wine, and liquor were assessed separately. • Participants who wrote “0” or left the alcohol consumption section blank* were classified as nondrinkers. • Participants who did not provide interpretable alcohol-intake information, who reported past but not current alcohol intake, or who reported implausibly high alcohol intake (≥30 drinks per day) were excluded from this analysis. *A total of 394,032 participants left the alcohol section blank.
Were the outcomes measured in the same way in the groups being compared? • Yes. • Mortality outcomes were assessed via personal inquiry from 1982–1988 then through linkage to the National Death Registry through 2006.
Was follow-up sufficiently complete? • Yes. • Death certificates and cause-of-death codes were obtained for >99% of known deaths in the sample.
What are the Results? • How strong is the association between exposure and outcomes? • How precise is the estimate of the risk?
How strong is the association between exposure and outcome? How precise is the estimate of the risk? *Adjusted for age, sex, race/ethnicity, education, marital status, body mass index, family history of pancreatic cancer, and history of gallstones or diabetes mellitus. †Adjusted for age, sex, race/ethnicity, education, marital status, body mass index, family history of pancreatic cancer, and history of gallstones, diabetes mellitus, or smoking.
How Can I Apply the Results to Patient Care? • Were the study patients similar to the patients in my practice? • Was the duration of follow-up adequate? • What was the magnitude of the risk? • Should I attempt to stop the exposure?
Were the study patients similar to the patients in my practice? • The sample included 576,697 women and 453,770 men aged ≥30 years from across the US and including the District of Columbia and Puerto Rico.
Was the duration of follow-up adequate? • Follow-up was 14 years.
What was the magnitude of the risk? • Never smokers had a 36% higher risk of pancreatic cancer mortality associated with consumption of 3 or more drinks per day (largely confined to those who drank liquor) compared with nondrinkers. • Ever smokers had a 16% higher risk after adjustment for smoking history and other covariates.
Should I attempt to stop the exposure? • Patients should be counseled that consumption of 3 or more drinks per day of liquor is associated with an increased risk of pancreatic cancer compared to not consuming alcohol.