Terry is 52 years old and has a 3 month history of intermittent tingling and pain in his right thumb and index finger which is worse at night. This can radiate up to his wrist. He is right-handed and this is affecting his work in a jeweller. Based on his history you suspect he may have Carpal tunnel syndrome and review factors in his past medical history.
Which one of the following factors is not a recognised association with this condition?