I'll bet I get a lot of food answers to this one.
The waist measures larger than the hips.
Shortness of breath when making physical effort in normal daily activities.
Smoking tobacco (probably weed too but we don't know yet.)
Lack of the right kind and amount of exercise.
Poor nutrition.
Diabetes.
High blood pressure.
Depression.
Me. Ready for my second one and don't give a crap.
I'd have to say stress,
I read that each year hundreds of people die while climbing in the mountains. Some become victims of falling rocks or unforeseen health problems, such as a heart attack.