Barrgghh
For completely unscientific observations, they also appear physically older too.
This sounds plausible, if we assume having a “old person” mentality is correlated with things we know age people faster like stress, lower physical activity, and less cognitive stimulation, and that on top of it, it also influences how people dress and body language, it wouldn’t be surprising it would make people look older.
On the other one, some “youthful” behaviours, like not sleeping enough or substance abuse, will also age people in their 30s very fast.