Rheum has a lot of people in their 20s- 40s with lupus and RA. My family med rotation had a higher % elderly people than my rheum rotation.
This is true.
Cardiology is a geriatrics specialty these days. Sure you will get the middle aged guy with STEMI that you intervene on, but then they eventually get heart failure down the road. CHF is huge, and it is all a bunch of all people with CAD and systolic CHF.
GI, is pretty variable, though the majority of your practice will be 50 and up given malignancy screening starts at 50. But it is variable because you also get a lot of young women with functional abdominal symptoms like IBS. Though i'm sure that isn't what most people going into GI find exciting. GI bleeds on 30-50 year old alcoholics gives the variety.
Urology, old dudes with BPH.
Optho, cataracts on the medicare crowd. Retina taking care of DM retinopathy on oldies as well as macular degeneration.
Neph, lots of old people with long standing hx of DM/HTN on HD.
Pulm/Critical Care: bunch of old people in the unit who should have filled out advanced directives.
Radiology: reading all the studies ordered on all the old sick people all day.
I can go on.
I say some of this tongue and cheek, but it isn't too far from the truth. The group who utilizes the most healthcare are the medicare population.