Tobacco linked to global trends in bladder cancer

The incidence and associated mortality rates of bladder cancer worldwide appear to be correlated with the rates of tobacco use, a recent study has found.

Researchers retrieved data on bladder cancer rates from three sources: the GLOBOCAN database, the Cancer Incidence in Five Countries, and the WHO mortality databases. Tobacco use was determined through information from the WHO Global Health Observatory.

In 2018, the researchers found 549,393 new cases of bladder cancer leading to 199,922 related deaths. These rates varied widely between sexes and across geographical regions. In men, for instance, age-standardized rates (ASRs) of bladder cancer ranged from as low as 1.3 per 100,000 in middle Africa to a maximum of 26.5 per 100,00 in Southern Europe.

Sex-stratified bladder cancer mortality rates were 3.2 and 0.9 per 100,000 in men and women, respectively.

Notably, researchers detected a positive correlation between tobacco use and bladder cancer incidence (r, 0.20) and mortality (r, 0.38) in men. This was also true in women, but the effect of tobacco use on cancer incidence was stronger (r, 0.67), while its influence on associated mortality was weaker (r, 0.22).

This was confirmed through multivariable linear regression analysis of bladder cancer incidence (men: coefficient, 0.152, 95 percent confidence interval [CI], 0.017–0.286; p=0.027; women: coefficient, 0.116, 95 percent CI, 0.078–0.154; p<0.001). Mortality, on the other hand, was only significantly associated with tobacco use in men (coefficient, 0.067, 95 percent CI, 0.025–0.108; p=0.002).

“Tobacco use was significantly associated with both bladder cancer incidence and mortality. Hence, a global effort to promote smoking cessation is extremely important to reduce bladder cancer incidence and mortality in the long run,” the researchers said.