Alcohol drinking and bladder cancer risk: a meta-analysis.
BACKGROUND
We aimed at investigating the risk of bladder cancer at different levels of alcohol consumption by conducting a meta-analysis of epidemiological studies.


METHODS
In October 2010, we carried out a systematic literature search in the Medline database, using PubMed. We identified 16 case-control and 3 cohort studies, including a total of 11 219 cases of bladder cancer, satisfying the inclusion criteria for this meta-analysis. Moderate alcohol intake was defined as <3 drinks per day (i.e. <37.5 g of ethanol per day) and heavy intake as ≥3 drinks/day. Pooled estimates of the relative risks (RR) and the corresponding 95% confidence intervals (CI) were calculated using random effects models.


RESULTS
Compared with non-drinkers, the pooled RRs of bladder cancer were 1.00 (95% CI 0.92-1.09) for moderate and 1.02 (95% CI 0.78-1.33) for heavy alcohol drinkers. When we excluded four studies that did not adjust for tobacco smoking, the corresponding estimates were 0.98 (95% CI 0.89-1.07) and 0.97 (95% CI 0.72-1.31).


CONCLUSIONS
This meta-analysis of epidemiological studies provides definite evidence on the absence of any material association between alcohol drinking and bladder cancer risk, even at high levels of consumption.
Department of Epidemiology, Mario Negri Institute for Pharmacological Research, Milan, Italy. claudio.pelucchi@marionegri.it
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Pelucchi
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Galeone
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Tramacere
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Bagnardi
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Negri
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Islami
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Scotti
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Bellocco
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Corrao
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Boffetta
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La Vecchia
D000428:Alcohol Drinking / Q000009:adverse effects*; D016022:Case-Control Studies; D015331:Cohort Studies; D006801:Humans; D015999:Multivariate Analysis; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000209:etiology*