Table 3.
Odds ratios and 95% confidence intervals from univariate logistic regressions for environmental explanatory variables, models 1 and 2
| Model 1: Serosurvey dataset alone† | Model 2: Serosurvey and clinical cases dataset combined‡ | |||||
|---|---|---|---|---|---|---|
| OR | 95% CI | P value | OR | 95% CI | P value | |
| Continuous predictors* | ||||||
| Agricultural lands | 0·77 | 0·61–0·99 | 0·04 | 0·73 | 0·59–0·91 | 0·004 |
| Developed lands | 1·32 | 0·49–3·50 | 0·58 | 0·94 | 0·44–2·00 | 0·87 |
| Wooded wet lands | 2·70 | 0·89–8·17 | 0·08 | 5·20 | 1·63–16·6 | 0·005 |
| Non-wooded wetlands | 3·85 | 0·09–163 | 0·48 | 10·7 | 0·43–269·8 | 0·15 |
| Surface water | 1·03 | 0·55–1·93 | 0·93 | 1·14 | 0·53–2·44 | 0·74 |
| Dry bare land | 14·7 | 0·64–338 | 0·09 | 6·39 | 0·11–380·6 | 0·37 |
| Categorized predictors | ||||||
| Hardwood forest | ||||||
| <14·3% | Ref. | Ref. | ||||
| ⩾14·3% | 3·18 | 0·92–11·0 | 0·07 | 4·43 | 1·87–10·5 | 0·0007 |
| Mixed forest | ||||||
| <5·8 | Ref. | Ref. | ||||
| 5·8–13·2 | 2·23 | 0·41–12·2 | 0·35 | 4·16 | 1·37–12·7 | 0·012 |
| ⩾13·2 | 2·95 | 0·61–14·3 | 0·18 | 5·87 | 1·78–19·3 | 0·004 |
| Coniferous forest | ||||||
| <3·9 | Ref. | Ref. | ||||
| ⩾3·9 | 1·50 | 0·46–4·84 | 0·50 | 2·13 | 1·07–4·24 | 0·032 |
| Orchards | ||||||
| <0·16 | Ref. | Ref. | ||||
| ⩾0·16 | 0·39 | 0·35–6·20 | 0·60 | 0·34 | 0·10–1·15 | 0·08 |
OR, Odds ratio; CI, confidence interval; Ref., reference category.
*
OR presented for an increase of 10% of the area represented by the selected land cover within a buffer of 5 km radius around the barn.
†
Based on serosurvey database, 2012 (n = 190 horses).
‡
Merged data from the serosurvey and the clinical cases database (n = 224 horses).