Research news: October 2011
We’ve long known that smoking is the most important modifiable risk factor for bladder cancer. A new study quantifies the excess risks in contemporary populations. Nearly half a million US citizens in the National Institutes of Health Diet and Health Study cohort reported their smoking habits and were then followed up over 11 years. During that period new bladder cancer was recorded in about 4500 participants.
Compared with people who had never smoked, those who had reported smoking regularly had a fourfold increased risk of bladder cancer, with a number needed to harm of 727. The risk was doubled in former smokers compared with never smokers; for every 1250 former smokers, one extra bladder cancer was diagnosed.
About half of all bladder cancers could be avoided among both men and women if everyone stopped smoking. This contrasts with earlier studies, where the population attributable risk of bladder cancer for