An analysis of cancer and heart diseases rates amongst people who have been to space has found no difference to the general population on Earth
Source:
https://www.newscientist.com/article/2208725-astronauts-dont-seem-to-be-dying-from-exposure-to-space-radiation/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home