Correlation Analysis between Bladder Cancer and Cigarette Smoking in Various Countries.

Cigarette smoking is considered to be a risk factor of bladder cancer. We investigated the relationship between bladder cancer mortality rates and cigarette smoking prevalence in various countries, and examined whether only the difference of smoking prevalence could explain the difference of mortality rates of bladder cancer in each country or not. The age-adjusted mortality rates from bladder cancer were high in European countries and low in Asian countries. The sex ratios ranged between 2 to 6 in most of the countries. For 20 countries, the mortality rate from bladder cancer was not correlated with the cigarette smoking prevalence. However, when the analysis was restricted to 16 countries in Europe, North America and Oceania (Caucasians), the correlation coefficients between them were high, being 0.68 (p < 0.01) in males and 0.49 (0.05 < p < 0.1) in females. In both Japan and the United States, cigarette smoking prevalence declined while the incidence of bladder cancer increased in males, both being stable in females. Race might be considered to be a strong risk factor of bladder cancer, followed by the prevalence of cigarette smoking. It is necessary to follow the changes of incidence rates of bladder cancer in the future to evaluate the influence of cigarette smoking.