Park YS, et al: Microscopic Colitis in Korea 183 Table 1. Clinical Characteristics of the Enrolled Patients Feature Mean age, yr M:F Duration, wk Frequency Normal pathology (n=71) 44.3±17.8 1.45:1 46.0±79.5 4.60±2.4 Suspicious LC (n=4) 51±14.1 1:1 131.0±246.0 6.3±2.6 Suspicious CC (n=3) 44.67±13.3 2:1 121.33±155.2 3.3±0.58 LC, lymphocytic colitis; CC, collagenous colitis. LC (n=18) 43.17±19.0 2:1 150.7±232.0 4.1±2.5 Fig. 3. Age distribution of microscopic coltis. LC, lymphocytic colitis; CC, collagenous colitis. and normal tissue group. For the comparisons of MC group and suspicious MC group and normal tissue, one-way ANOVA was used. Chi-square test was used for relation between drugs and autoimmune disease, and for statistics, SPSS 12.0 program (SPSS Inc., Chicago, IL, USA) was used. RESULTS 1. Clinical characteristics of patients We enrolled 100 patients with chronic diarrhea, 58 males and 42 females, who show normal colonoscopic finding. The mean age was 45 years old. Twenty-two patients were diagnosed as microscopic colitis (22%), 10 were females and mean age was 44.9±18.0 years. Seven patients were diagnosed with suspicious microscopic colitis (7%). There were 18 cases of lymphocytic colitis, 4 cases of collagenous colitis, 4 of suspicious LC and 3 of suspicious CC (Fig. 2). There was no significant difference among MC group, suspicious MC group and normal tissue group in clinical characteristics. All three groups varied in the number of diarrhea and the period of having diarrhea (Table 1). While patients with microscopic colitis with lymphocytic colitis were in their 20s, patients with collagenous colitis were in their 70s (Fig. 3). CC (n=4) 67.0±9.6 0:4 16.5±22.4 5.3±1.9 1 (25.0) 1 (25.0) 0 2 (50.0) 0 Table 2. Distribution of Involved Colonic Segments of Microscopic Colitis Distribution LC (n=18) CC (n=4) Ascending colon Transverse colon Descending, sigmoid colon, rectum Entire colon More than 2 segments Data are presented as number (%). LC, lymphocytic colitis; CC, collagenous colitis. 5 (27.8) 2 (11.1) 3 (16.7) 1 (5.5) 7 (38.9) 2. Distribution of microscopic colitis Followings are the pathological lesions of 22 patients: 6 cases in the ascending colon (30%), 3 in the transverse colon (15%), 3 in the descending colon and the rectum (15%). Only 3 showed diffuse distribution throughout the colon (15%), and more than two segments of the colon were involved in 5 patients (15%) (Table 2). 3. Drug related microscopic colitis From 100 days prior to the development of diarrhea, we took drug history including NSAIDs, proton pump inhibitor (PPI), lipid lowering agents, aspirin and other anticoagulants for more than 2 weeks. The relation between each medicine and micro- scopic colitis was not statistically significant. However, 7 of the 22 patients with microscopic colitis (32%) showed suspicious drug consumption. Taking NSAIDs was in 4 cases (18.2%), one case taking aspirin and clopidogrel and another case taking aspirin, simvastatin, and NSAIDs. NSAIDs were related with 2 patients with collagenous colitis and 2 lymphocytic colitis. Two patients with collagenous colitis improved diarrhea a month after discontinuing the suspicious NSAIDs as well as aspirin and clopidogrel. 4. Relation to autoimmune disease Among 22 patients with microscopic colitis, 4 patients (18.2%) presented autoimmune disease: 2 thyroid disease, 1 type 1 dia- betes, and 1 idiopathic hypereosinophilic syndrome. There is significant correlation between microscopic colitis and autoim-