I have to imagine various addictions are rampant among the Clans. They are a society of traumatized child soldiers, with little or no emotional support or outlet. With no psychiatric care, they would be self medicating left, right and sideways. But as long as you can sober up before the trial starts and pull off a victory, nobody cares.
Pain meds are particularly susceptible for abuse, even if they are fancy non-habit forming space drugs. The push to get back in the action after an injury means patients are likely to take a fist full of advil and go back too soon. That means re-injury. Assuming this isn't Star Trek Magi-medicine, there well be side effects and counter-indications. Those may require more drugs to manage. Tylenol, for example, has some rather nasty effects on the liver and the dosage is something like less than double the recommended levels. I'm not suggesting liver issues in particular but illustrating a knock-on effect.
Depending on how you want to fluff the Elemental BA requiring a pilot of elemental size, that could lead vascular or musculo-skeletal problems. The using the suit results in wide spread bruising, you could see vascular problems. The same groups of capillaries are ruptured over and over and over again, leading to formation of scar tissue. Elementals might take anti-coagulants to prevent a clot from all that bruising from going some place bad. Which in turn can lead to issues treating wounds, requiring the application of additional coagulants. Years spent fighting in/against a BA suit would probably do some damage to the muscles and ligaments.
Aero pilots are described as very thin and sometimes frail. If the Scientists went a step beyond and intentionally reduced bone density, then they would be at higher risk of bone fracture. The oversize head, combined with slender builds could lead to chronic neck and shoulder issues.
The bouncing of a mech must be brutal on the pilot's spine, unless there is special damping in the cockpit or just the command couch.
