Which of the following statements about the etiology of chronic ulcerative colitis are true?

A. Ulcerative colitis is 50% less frequent in nonwhite than in white populations

C. Cytokines are integrally involved in the pathogenesis of ulcerative colitis.

D. Ulcerative colitis has been identified with a greater frequency in family members of patients with confirmed inflammatory bowel disease

E. Ulcerative colitis is two to four times more common in Jewish than in non-Jewish populations.

DISCUSSION: Despite intensive investigation, the specific cause of ulcerative colitis remains unknown. There appears to be a clear genetic component involved in the etiology and distribution of ulcerative colitis. It is significantly less frequent in nonwhite than in white populations and significantly more frequent among Jews than among other populations. There is a strong familial concordance by disease category: the prevalence of inflammatory bowel disease is 10% to 25% in relatives of patients with confirmed Crohn's disease or ulcerative colitis. There is considerable uncertainty about the fundamental role of infectious agents in the primary pathogenesis of ulcerative colitis. Psychological factors may play a role in exacerbations of the disease, but they are not of primary importance in its pathogenesis. Recent studies have suggested that cytokines and other immunoregulatory substances are integrally involved in the pathogenesis of inflammatory bowel disease.