South Carolina State University experts analysed the fumes released by burning candles in lab tests. They found paraffin wax candles gave off harmful fumes linked to lung cancer and asthma - but admitted it would take many years' use to risk health...It's very possible the cited study is scientifically valid, but the endless proliferation of "xyz causes cancer" blurbs in the press I think must eventually inure the public to the serious carcinogenic risks in the world. When people are given the impression that everything causes cancer or everything causes heart disease, they may eventually consider the situation hopeless and give up on following proper health habits.
Photo credit for Hogwarts candles.