Hello there..., I went through your query.... There are various causes other than Diabetes which can cause tingling and numbness in the hand... Some of the other causes include vitamin b12 deficiency, vasculitis, etx..., in your case i think probably it could be due to vitamin b12/deficiency.....Eat non vegetarian foods...As it is only the source of vitamin b12..... Consider B complex supplements.... Consult your Physician if symptoms persists...