Death and major cardiovascular events during the study period among people who experienced mild gastroenteritis (n = 414), severe gastroenteritis (n = 153) or no gastroenteritis (n = 331) during the Escherichia coli O157:H7 outbreak and among a control population (n = 11 263) from the surrounding communities
| Group | No. (%) | No. of events per 1000 person-years | Hazard ratio (95% confidence interval) | |
|---|---|---|---|---|
| Unadjusted | Adjusted* | |||
| Death or major cardiovascular event | ||||
| Residents of surrounding communities | 1115 (9.9) | 13.4 | 1.0 (ref) | 1.0 (ref) |
| Walkerton Health Study participants | ||||
| No gastroenteritis | 28 (8.5) | 11.4 | 0.85 (0.60–1.22) | 1.05 (0.72–1.53) |
| Mild gastroenteritis | 22 (5.3) | 6.9 | 0.52 (0.34–0.79) | 0.64 (0.42–0.98) |
| Severe gastroenteritis | 9 (5.9) | 7.9 | 0.60 (0.31–1.12) | 0.74 (0.38–1.43) |
| Major cardiovascular event (death censored) | ||||
| Residents of surrounding communities | 536 (4.8) | 6.5 | 1.0 (ref) | 1.0 (ref) |
| Walkerton Health Study participants | ||||
| No gastroenteritis | 8 (2.4) | 3.3 | 0.51 (0.25–1.01) | 0.61 (0.30–1.22) |
| Mild gastroenteritis | 13 (3.1) | 4.1 | 0.64 (0.37–1.10) | 0.75 (0.43–1.30) |
| Severe gastroenteritis | 6 (3.9) | 5.3 | 0.82 (0.37–1.81) | 1.04 (0.46–2.33) |
| Death (all causes) | ||||
| Residents of surrounding communities | 684 (6.1) | 8.1 | 1.0 (ref) | 1.0 (ref) |
| Walkerton Health Study participants | ||||
| No gastroenteritis | 20 (6.0) | 8.0 | 1.0 (0.64–1.55) | 1.29 (0.82–2.01) |
| Mild gastroenteritis | 10 (2.4) | 3.1 | 0.39 (0.21–0.71) | 0.52 (0.29–0.97) |
| Severe gastroenteritis | † | † | † | 0.39 (0.13–1.21) |
↵* Adjusted for age, sex, neighbourhood income quintile, number of comorbidities, number of family physician visits in the 2 years before the outbreak, chronic obstructive pulmonary disease, diabetes, hypercholesterolemia and chronic kidney disease before the outbreak.
↵† Not reported because of count data less than 6. With such low counts, there is a risk of reidentification using Institute for Clinical Evaluative Sciences data. This is under the agreement between the Institute for Clinical Evaluative Sciences and the privacy officer of Ontario.