A common health problem
During the 1920s “colitis” was a fashionable diagnosis, used unspecifically for a wide range of disorders. An increase in the number of cases was seen up until the 1980s after which the number of patients seems to have stabilised. The most recent reports show a tendency to declining numbers of Ulcerative colitis patients, occurring at the same time as an increase in the number of Crohn’s patients. The overall number of patients with IBD (Ulcerative colitis + Crohn's disease) is currently increasing.
Inheritance and environment
Clearly, both Ulcerative colitis and Crohn's disease have multifactor origin. Twin studies from Sweden, Denmark and UK have demonstrated that genetic factors explain approximately 6-16 % of Ulcerative colitis cases. Environmental factors appear to be of more importance than genetic predisposition in the development of Ulcerative colitis. Ambiguously enough, in contrast to Crohn's disease, cigarette smoking, in these cases seems to have a preventive role. However, former smokers appear to have an increased risk of developing Ulcerative colitis. Due to the well-documented risks with tobacco, smoking is generally not advocated as therapy in Ulcerative colitis. Nicotine patches have been shown to be moderately effective in Ulcerative colitis.
Surprisingly enough, no clear link has been established between special diets and the risk of either Ulcerative colitis, or Crohn's disease. However refined sugar, margarine, baker’s yeast and cola drinks have been listed as presumptive environmental risk factors.