Question

For situations in which the disease of interest (urinary bladder cancer, in this case) is very rare, which type of epidemiologic study will be more likely to result in a significant result when there is a true association between the risk factor and disease? Why is this so?

Answer 1

Epidemiology of Bladder cancer(BC) :

BC is the most common malignancy of the urinary tract, the 7th most common cancer in men and the 17th in women . The worldwide age-standardized incidence rate is 9 per 100,000 for men and 2 per 100,000 for women (2008 data) .

In the European Union (EU), the age-standardized incidence rate is 27 per 100,000 for men and 6 per 100,000 for women [1]. The incidence of BC varies between regions and countries; in Europe, the highest age-standardized incidence rate has been reported in Spain (41.5 in men and 4.8 in women) and the lowest in Finland (18.1 in men and 4.3 in women) .

Worldwide age-standardized mortality rate is 3 for men versus 1 per 100,000 for women. In the EU, the age-standardized mortality rate is 8 for men and 3 per 100,000 for women, respectively . In 2008, BC was the eighth most common cause of cancer-specific mortality in Europe .

The incidence of BC has decreased in some areas, possibly reflecting the decreased impact of causing agents, mainly smoking and occupational exposure . Mortality from BC has also decreased, possibly reflecting an increased standard of care.