A scented candle can increase the levels of formaldehyde in your home therefore increasing your cancer risk; Driving to work holds an inherent risk of death; eating an apple without washing it means your eating various pesticides; Taking lifesaving meds from your Dr can increase the risk of a number of things (depending on the med). etc, etc, etc.
Nothing in this life comes without some form of inherent danger, but you cant go around scared of everything. Sometimes you have to pick the best option ( e.g. vaping rather than smoking) & live with your choices.
I for one enjoy vaping & I KNOW that is better for me than smoking, so I will live with whatever tiny extra risk this may add to my life & I'm happy to do so.