Unfortunately the german workers' compensation board (i don't know if there is a comparable in the other countries), with a compulsary membership for all workers, exclusive responsible for occupational diseases/occupational accidents,
have found out, after a lot of intensive studies on the highest science level:
There is no context between helicopterflying and back problems!
Also there is no context between helicopterflying and hardness of hearing, because pilots do allways wear their headsets.
But Dr Germany found a linkage between hardness of hearing and a to high radio level with a probability of 10%. Wow!
The compensation board is to forget for diseases, but in case of an accident there is no better insurance in Germany.