Smartphones could speed up your chance of psoriatic arthritis

[Caroline]

An interesting study
I use a smartphone a lot, but haven’t noticed a difference in my digit joints... possibly because I use the smartphone differently and only use one finger to type  

I don't have one so wouldn't know.

I have one, and use it intensively with both thumbs. I never use my nails, a smartphone just does not react to your nails   (who did this research?) Never found any relation between smartphone use and arthritis.
Also on my iPad, which I use with ten finger typing, I have no problems.
On the opposite, I feel that since I stopped working with standard Logitech or Microsoft keyboards, where I really did feel my joints, and switched to Apple keyboards, which work much lighter, and my iPad, which only needs very light taps, the pain in the joints of my fingers has greatly been reduced. (Of course this may also be due to my treatment).