Just an after-thought to my earlier post, and in contrast to some of the posts above, if you google nicotine and Crohn's (or nicotine and ulcerative colitis) there's quite a body of opinion, and several trials, that indicate that nicotine may help prevent/ reduce the symptoms. While smoking carries more health risks than it would likely solve in this regard (and, forgive me, is a horrible, smelly habit IMHO!), vaping - although outwardly it might at first appear similar - is completely different (and nicotine is not carcinogenic BTW - it's primarily the tar and myriad other chemicals in cigarette smoke that's harmful).
For those who may not know, Vaping - I prefer the term to e-cigarette as none of the PV's (Personal Vaporizers) I and many others use look anything like a cigarette - as the name suggests produces vapour, not smoke and is available in a wide range of nice flavours (and strengths) rather than just tobacco flavour - although, if that's what you like, that's available too!