Injury from plane crash or terrorist attack id say
The short term outcome with underage drinking would be heart disease because it gives you a high blood pressure, stroke or even sudden cardiac death.
The best way is to eat enough of protein every day. Different recommendations can be found but a very good ballpark is that you eat around 0.6-0.8g or protein per pound of your own weight.
Another and more important thing is to add a weight training regimen into your life which will help and slow down muscle loss.
D.non-modifiable determinates,health deductibles Sub hope this helps :)