I don't see any reason that wearing Adult disposable diapers could cause an adult any harm.
Many incontinent people wear diapers because they can't control their bladder or bowels and there other health is just fine.
You might get a diaper rash from wearing diapers though but that can be prevented by changing your adult diapers often, showering regularly, and wiping your diaper area clean after every diaper change.
You can also avoid diaper rash too by applying diaper rash cream before each new diaper.