Volume 8, Number 1—January 2002
Research
Participant Blinding and Gastrointestinal Illness in a Randomized, Controlled Trial of an In-Home Drinking Water Intervention
John M. Colford*†
, Judy R. Rees*†, Timothy J. Wade*†, Asheena Khalakdina*†, Joan F. Hilton‡, Isaac J. Ergas*, Susan Burns*, Anne Benker*, Catherine Ma, Cliff Bowen, Daniel C. Mills, Duc J. Vugia, Dennis D. Juranek¶, and Deborah A. Levy¶
, Judy R. Rees*†, Timothy J. Wade*†, Asheena Khalakdina*†, Joan F. Hilton‡, Isaac J. Ergas*, Susan Burns*, Anne Benker*, Catherine Ma, Cliff Bowen, Daniel C. Mills, Duc J. Vugia, Dennis D. Juranek¶, and Deborah A. Levy¶Table 1
Baseline characteristics of 236 participants in Pilot Water Evaluation Trial
| Characteristic | Sham (n = 118) | Active (n = 118) |
|---|---|---|
| Age (Years) | n (%) | n (%) |
| <11 | 28 (24) | 29 (25) |
| 12-19 | 10 (8) | 13 (11) |
| 20-29 | 9 (8) | 4 (3) |
| 30-39 | 22 (19) | 18 (15) |
| 40-49 | 21 (18) | 24 (20) |
| 50-59 | 16 (14) | 14 (12) |
| >60 | 12 (10) | 16 (14) |
| Sex (%) | n (%) | n (%) |
| Female | 57 (48) | 56 (48) |
| Male | 61 (52) | 62 (52) |
| Prior medical conditions | n (%) | n (%) |
| Crohn’s disease | 1 (1) | 0 (0) |
| Diverticulitis | 1 (1) | 3 (3) |
| Frequent heartburn | 5 (4) | 8 (7) |
| Irritable bowel syndrome | 7 (6) | 2 (2) |
| Milk intolerance | 4 (3) | 5 (4) |
| Stomach ulcer | 5 (4) | 4 (3) |
| Ulcerative colitis | 0 (0) | 1 (1) |
| Migraine headaches | 14 (12) | 13 (11) |
| Self-assessment of current health | n (%) | n (%) |
| Excellent | 42 (36) | 41 (35) |
| Very good | 54 (46) | 53 (45) |
| Good | 20 (17) | 20 (17) |
| Fair | 2 (2) | 4 (3) |
| Poor | 0 (0) | 0 (0) |
| Current medical conditions (prior 7 days) | n (%) | n (%) |
| Abdominal cramps | 19 (16) | 15 (13) |
| Diarrhea | 14 (12) | 13 (11) |
| Nausea | 16 (14) | 11 (9) |
| Vomiting | 2 (2) | 3 (3) |
| Fever | 6 (5) | 5 (4) |
| Pregnant | 1 (1) | 1 (1) |
