The origins of the word are even less elegant. It refers to people (originally male) who were without figa, the colloquial word for "vagina." Thus a loser was quintessentially a guy who couldn't get any.
A popular saying tells us that la fortuna e' cieca ma la sfiga ci vede benissimo: luck is blind but bad luck can see perfectly.
In my experience Italians are more superstitious than us and really do believe more in luck as a factor in life. For example, Italian men sometimes will touch their private parts (toccarsi le palle) as a way to ward off impending sfiga.