I think there's probably more going on than that one chemical. For example, if I don't go jogging for a week and then go for a run my shirt later after it dries smells like urine. I looked up why and it's because urea builds up in your skin and is excreted with sweat. Maybe this fact just made me paranoid but I swear that I can smell a urea smell on my skin when I don't exercise regularly.
I imagine elderly people aren't out sweating regularly.
I imagine elderly people aren't out sweating regularly.