Table 2.
Outbreak, outbreak establishment, and outbreak investigation characteristics associated with contributing factor identification, single-setting outbreaks – National Environmental Assessment Reporting System (NEARS), 2009–2013a
| OR (90% CI) | P value | |
|---|---|---|
| Outbreak characteristics | ||
| Primary etiologic agent identified (N = 291) | ||
| Yes | 3·27 (2·10–5·10) | <0·001 |
| No | – | – |
| Outbreak type (N = 195) | ||
| Viral | 0·80 (0·44–1·47) | 0.547 |
| Bacterial | – | – |
| Toxinb | ||
| Food vehicle identified (N = 267) | ||
| Yes | 1·34 (0·87–2·05) | 0.261 |
| No | – | – |
| Outbreak establishment characteristics | ||
| Establishment type (N = 291) | ||
| Restaurant | 1·38 (0·76–2·50) | 0.372 |
| Other | – | – |
| Menu type (N = 291) | ||
| American | 0·91 (0·60–1·38) | 0.712 |
| Other | – | – |
| Establishment food preparation process type (N = 291) | 0.572 | |
| Complex | 0·76 (0·31–1·86) | 0.613 |
| Cook serve | 0·52 (0·18–1·55) | 0.328 |
| Prep serve | – | – |
| Establishment serves raw or undercooked food (N = 291) | ||
| Yes | – | – |
| No | 0·76 (0·48–1·21) | 0.327 |
| Ownership type (N = 262) | ||
| Chain | 1·36 (0·85–2·19) | 0.282 |
| Independent | – | – |
| Meal preparation location (N = 261) | ||
| All meals prepared on location | 2·14 (1·14–4·00) | 0.046 |
| Meals fully or partially prepared at another location | – | – |
| Approximate number of meals served daily (N = 249) | ||
| 1–150 | – | – |
| >150 | 1·78 (1·12–2·81) | 0.039 |
| Outbreak investigation characteristics | ||
| Time to contact (N = 277) | ||
| Same day | 1·86 (1·16–2·97) | 0.030 |
| 1–5 daysc | – | – |
| 6–27 daysc | – | – |
| Number of visits made to complete environmental assessment (N = 285) | ||
| 1 or 2 | – | – |
| ⩾ 3 | 1·87 (1·06–3·31) | 0.070 |
a
Denominators vary because of missing data for the explanatory variables.
b
Because of small cell size, the toxin category was not included in this analysis; odds ratio is ‘viral’ vs. ‘bacterial.’ c Because of small cell size, these two categories were collapsed for odds ratio analyses; odds ratio is ‘same day’ vs. ‘one or more days.’