It may seem counterintuitive, but the opposite is actually true.
A dull knife requires more force to cut with than a sharp one. Needing to use more pressure to cut makes it more likely you will have an accident with your knife, slip while using it, etc.
Furthermore, a cut from a dull knife can be worse than a cut from a sharp knife because the dull edge actually tears the tissue instead of cutting it. Torn tissue does not repair or heal as well, or as quickly, and is more prone to infection, while a cut from a sharp knife seals and heals much better. (Just think about how sharp a surgical tool is).
I suggest you keep your knives as sharp as you are comfortable with.