Too much lettuce could lead to wet tail.
Not true Thank god! Wet Tail is a terrifying disease! It can lead to diarrhoea and kidney/liver damage though.
Wet Tail is caused my either E.Coli or L. Intracellurlaris. It's a bacterial disease (hence its contagious) but not from what an animal has eaten, though I guess its like white spot is to fish, can be stress induced.
Again, this might interest you?
http/hamster.etla.org/cgi-bin/topic_show.pl?tid=59
My current syrian is 4 years+ and counting (i reckon he is closer to 5) but i used to own as many as 50 hamsters, not counting the numerous rats and mice and gerbils and an opossum and gambian pouched rats and the reptiles and the rabbits and guinea pigs etc. I even showed Syrian Hamsters for a bit, though that was mainly just to prove a point the NHC (national hamster council) are a bunch of elitist snobs and didnt like people who had opinions so I entered 5 hamsters in one show and knocked them down a bit taking several 1sts, 2nds, 3rds, reserves, best in class, best small breeder and best in show or to that extent. Needless to say they definately didnt like me any more after that! Especially as they were all our own bred hamsters, lots of people buy other peoples hamsters and show them and take the glory... We didnt though lol.