yes, VIT+2 = 1 DEF, easily tested by any VIT ring with an even number(i.e +2,+4)
for example, Stamina Ring, Lv.14 VIT+2, DEF rises from 166 with no ring in that slot, to 167 when i equip that ring, so yes, VIT+2 = 1 DEF, as with STR, STR+2 = 1 ATT, etc.
Edited, May 21st 2009 6:09pm by LanceCPL