I haven't read the all the replies, so I might just repeat something.
I have been a blood donor for almost 20 years. My hbg i always high, but in resent years my ferritin is very low.
In 2014 i got Tinitus and a severe headace (with auora). The was just after giving blood, but i did not suspect the donation of blood to have anything to do with it.
Beforehand, I had experienced tinnitus many times for short periods, like 5 minutes or so, and then it would go away. But this time, the tinnitus was louder, both the tone and it also sounded like wind in my ears. Luckily, the windy sound went away the next day, but the sound of a tone has stayed with me since.
Since then, I have noticed, that my tinnitus gets very loud right after giving blood. So I have tried to observe/document my tinnitus before and after blood donation.
I gave blood yesterday, when i was back home, the tinitus was very loud and much louder than it has been for the past 2-3 months. And I hear the wind aswell.
So I suspect, that deficiency in some blood compounds can cause tinnitus, and that a blood donor might experience tinnitus, if this is the case. Ofcourse it might be a coincidence...or some other relation, that naturally occurs when I give blood.
My late grandfather did however say, that his tinitus vanished, when he started to take supplimemts with iron.
I have not decided to stop with donations. I hope to get my ferritin fixed instead.