By Kathleen Myers
People who smoke marijuana may be less likely to get bladder cancer than those who smoke cigarettes, a new study says.
Kaiser Permanente researchers compared the risk of bladder cancer in more than 83,000 men who smoked cigarettes only, marijuana only or both substances, USA Today reports. The men were aged 45 to 69, and they were examined over 11 years.
“Cannabis use only was associated with a 45 percent reduction in bladder cancer incidence, and tobacco use only was associated with a 52 percent increase in bladder cancer,” study author Dr. Anil A. Thomas, a fellow in urology at Kaiser Permanente Medical Center in Los Angeles, told USA Today.
More frequent marijuana use — smoking cannabis more than 500 times — was associated with greater risk reduction than smoking only once or twice. However, the study was critized for not including any non-smokers.
Thomas said the link does not prove a cause-and-effect relationship. However, he explained, “the theory is that there are receptors in the bladder that are affected by cannabis.”
Kaiser Permanente’s research comes on the heels of a September finding by a pair of scientists at California Pacific Medical Center in San Francisco that a compound derived from marijuana could stop metastasis in many kinds of aggressive cancer, including cancer in the breast, brain and prostate.