Elevated risk of cancer of the urinary tract for alcohol drinkers: a meta-analysis

Objectives: Recent narrative reviews have concluded that there is no suppor t for an association between alcohol consumption and urinary tract cancer. Many individual studies, however, have reported positive associations, alth ough rarely statistically significant. The purpose of this meta-analysis is to summarize and quantify this relationship with more statistical power an d to perform a sensitivity analysis on the study characteristics. Methods: We included 16 epidemiological studies published up to April 1999 and calculated summary odds ratios (SORs), both upgraded and adjusted for a ge, sex and smoking by meta-regression analyses. The age- and smoking- adju sted SORs (current alcohol drinking vs. non-drinking) were 1.3 (95% CI 0.9- 2.0) for six studies with men and 1.0 (95% CI 0.4-2.6) for four studies wit h women. Results: The age-, sex- and smoking-adjusted SOR was 1.2 (95% CI 0.9-1.7) f or seven studies with men and women combined. Conclusion: Even though studies differed in methodology, the results were r ather consistent. Subgroup analyses by type or amount of alcohol were not p ossible due to sparse data. We conclude that the available data suggest a s lightly increased risk of urinary tract cancer from alcohol consumption for men. The risk related to alcohol consumption for women and the influence o f the amount and type of alcohol remain unclear.