Table 1.
Demographic and clinical characteristics of study subjects
| Overall | Non-IBS | IBS | p value* | |
|---|---|---|---|---|
| Subjects, n | 7,725 | 6,180 | 1,545 | |
| Age group | ||||
| 20–39 years | 5,070 (65.6) | 4,056 (65.6) | 1,014 (65.6) | |
| 40–64 years | 2,290 (29.6) | 1,832 (29.6) | 458 (29.6) | 1.000 |
| 65 years or older | 365 (4.7) | 292 (4.7) | 73 (4.7) | |
| Area of residence | ||||
| Metropolitan | 5,065 (65.6) | 4,265 (69.0) | 800 (51.8) | <0.001 |
| Nonmetropolitan | 2,660 (34.4) | 1,915 (31.0) | 745 (48.2) | |
| Health insurance | ||||
| Regional insurance | 5,620 (72.8) | 4,919 (79.6) | 701 (45.4) | |
| Occupational insurance | 1,898 (24.6) | 1,057 (17.1) | 841 (54.4) | <0.001 |
| Medicaid | 207 (2.7) | 204 (3.3) | 3 (0.2) | |
| Economic status | ||||
| Lower | 1,207 (15.6) | 950 (15.4) | 257 (16.6) | |
| Lower middle | 1,997 (25.9) | 1,597 (25.8) | 400 (25.9) | 0.176 |
| Upper middle | 2,532 (32.8) | 2,059 (33.3) | 476 (30.6) | |
| Upper | 1,989 (25.7) | 1,574 (25.5) | 415 (26.9) | |
| Smoking | ||||
| None | 1,105 (95.6) | 692 (94.8) | 413 (96.9) | |
| Current | 40 (3.5) | 29 (4.0) | 11 (2.6) | 0.194 |
| Past | 11 (1.0) | 9 (1.2) | 2 (0.5) | |
| High-risk drinking | 23 (1.9) | 14 (1.8) | 9 (2.1) | 0.945 |
| Exercise | 74 (6.2) | 49 (6.4) | 25 (5.7) | 0.721 |
| Height, cm | 157.1±6.1 | 156.8±6.0 | 157.6±6.1 | 0.032 |
| Weight, kg | 55.7±8.1 | 56.3±8.4 | 54.6±7.6 | <0.001 |
| BMI, kg/m2 | 22.3±3.2 | 22.9±3.3 | 22.0±3.0 | <0.001 |
| Underweight (<18 kg/m2) | 146 (11.8) | 82 (10.4) | 64 (14.4) | 0.045 |
Data are presented as mean ± standard deviation or n (%). Metropolitan areas included Seoul, Incheon, Daejeon, Gwangju, Daegu, Ulsan, and Busan. Other areas were considered nonmetropolitan. Underweight is defined as BMI <18 kg/m2. High-risk drinking refers to alcohol consumption more than twice a week with the average amount of alcohol consumed being 5 drinks or more. Exercise refers to engaging any of the following during the past week: (1) strenuous physical activity for >20 min a day and >3 days a week; (2) moderate physical activity for >30 min a day and >5 days a week; or (3) or more. BMI, body mass index; IBS, irritable bowel syndrome.
p value between the non-IBS and IBS groups as calculated by the χ2 test or the Wilcoxon rank-sum test.