According to the National Cancer Institute – a branch of the National Institutes for Health – marijuana users are less likely to contract bladder cancer in comparison to their peers who do not smoke marijuana.
In an NCI study, about 82,050 people from different ages and socioeconomic backgrounds whose data was collected in 2002-03, were examined to find any connection between smoking marijuana or tobacco and the risk for bladder cancer. Of course, after analyzing the data, the researchers followed up with the respondents about 11 years later.
It is well known in the medical community that smoking tobacco causes bladder cancer. This study sought out to check if this happens when one smokes marijuana too. According to the data, smoking tobacco continued to be unhealthy, but the likelihood of this happening when you smoke marijuana reduced by 45 percent.
That said, about 41 percent of the group reportedly used cannabis while 57 percent of them used tobacco. Apart from this, 27 percent were found to have used both while 29 percent did not use either.
Researchers then adjusted for factors such as body mass index, ethnicity, race and age; they found that 45 percent of cannabis users were less likely to develop bladder cancer.
Of course, these findings do not prove causation but only association between the two. This can only mean that more research is required. What is also probable is that cannabis might have protective effect on the bladder. This could also point to the fact that cannabis users might just have healthier bladders given the amount of water they have to drink after its use.