Not really a term we use in the Uk but it means wear of the little joints in the back. Everyone over 18 has it. If you have back pain it might be an issue standing all day but if you are over 18 and symptom free I se no problem.
One wonders why any sensible organisation irradiates fit young applicants for a job. The risk from the radiation far outweighs any benefit, but I guess if you want the job you jump through the hoops