Questions. How are you calculating risk? What do the risk scores mean? How accurate are they? What responsibility do you bear if your tool is wrong and someone gets hurt?
I am not saying all this to be a wet blanket, but because these are real ethical and legal issues that must be considered when making claims about healthcare related products. Otherwise I think this is a cool idea and nifty piece of app building.
My personal advice: consider reframing this as something other than a “personal risk calculator”. Either that or add a lot of explanations and disclaimers.