Urinary bladder cancer and the petroleum industry: a quantitative review

To estimate the pooled risk of petroleum industry for urinary bladder cancer.

All observational studies that evaluated the association between urinary bladder risk and the petroleum industry were reviewed. We have only identified eight case-control studies. These studies were carried out between 1989 and 1995.

Of the eight localized studies six were exclusively for males. The other two studies included both males and females, but none reported separately the risk among men and women. There was an obvious risk of petroleum industry in the pooled risk (odds ratio 1.4, 95% confidence interval (CI) 1.27-1.54). Also, Q test was not significant (P>0.1), denoting homogeneity across the pooled studies. Pooled analysis applying the random effect model was 1.50 (95% CI 1.29-1.75).

Although our pooled estimate shows that the petroleum industry is associated with the risk of urinary bladder cancer, the eight studies were based on retrospective data from case-control studies. Further prospective studies evaluating the association between petroleum industry and urinary bladder cancer risk are strongly needed.