I did mention desk & office work

The forward head/shoulder postures of leaning forward to read books or papers at a desk can be a contributor.
This can slowly strain the neck over time, as well as closes the brachial plexus area where the nerves and blood flow to the arm & hands.
You would eventually start having some upper back and neck pain or discomfort if this is the case.

Some general thoughts...things be be aware of -
Do you tend to lean to one side or the other at the desk or often lean on one arm or the other?
shoulders uneven when looking in a mirror - one side dropped or raised?

If any of those posture things fit, being more aware and addressing those issues/habits might make your hand /arm symptoms lessen.