Table 4. Multivariate logistic regression analyses of symptoms reported by tick bite cases and erythema migrans (EM) cases.
| Symptoms of tick bite cases | Symptoms of EM cases | ||||||||||||||||||
| at baseline (n = 316) | at follow-up (n = 297) | Newly emerged among cases with: | at baseline (n = 277) | at follow-up (n = 240) | EM cases at follow-up versus baseline * | EM cases at baseline versus tick bite cases at baseline † | |||||||||||||
| Borrelia infection (n = 13) | no Borrelia infection (n = 259) | ||||||||||||||||||
| n | % | n | % | n | % | n | % | mOR | (95%CI) p-value | n | % | n | % | mOR | (95%CI) p-value | mOR | (95%CI) p-value | ||
| rash other than EM | 39 | 12.3 | 20 | 6.7 ‡ | 3 | 23.0 | 11 | 4.2 | ns | 28 | 10.1 | 15 | 6.3 | 0.4 | (0.2–1.0) p = 0.04 | ns | |||
| headache | 33 | 10.4 | 23 | 7.7 | 3 | 23.0 | 8 | 3.1 | 14.2 | (2.7–74.7) p = 0.01 | 61 | 22.0 | 43 | 17.9 | 0.4 | (0.2–0.8) p = 0.01 | 2.6 | (1.6–4.2) p<0.001 | |
| vomiting and nausea | 4 | 1.3 | 7 | 2.4 | 0 | 0 | 3 | 1.2 | ∼ | 2 | 0.7 | 3 | 1.3 | ns | ns | ||||
| impaired concentration | 8 | 2.5 | 10 | 3.4 | 1 | 7.7 | 6 | 2.3 | ns | 18 | 6.5 | 20 | 8.3 | 6.4 | (1.5–26.2) p = 0.01 | ns | |||
| elevated body temperature | 10 | 3.2 | 13 | 4.4 | 3 | 23.0 | 5 | 1.9 | ns | 19 | 6.9 | 14 | 5.8 | ns | ns | ||||
| myalgia | 34 | 10.8 | 26 | 8.8 | 2 | 15.4 | 12 | 4.6 | ns | 48 | 17.3 | 35 | 14.6 | ns | ns | ||||
| joint pain | 25 | 7.9 | 30 | 10.1 | 2 | 15.4 | 18 | 6.9 | ns | 41 | 14.8 | 33 | 13.8 | ns | ns | ||||
| blurred sight | 6 | 1.9 | 9 | 3.0 | 1 | 7.7 | 4 | 1.5 | ns | 8 | 2.9 | 7 | 2.9 | ns | ns | ||||
| tingling sensation in limbs | 19 | 6.0 | 15 | 5.0 | 2 | 15.4 | 8 | 3.1 | 14.8 | (2.3–93.7) p = 0.01 | 30 | 10.8 | 23 | 9.6 | ns | ns | |||
| pain in limbs | 18 | 5.7 | 18 | 6.1 | 2 | 15.4 | 8 | 3.1 | ns | 28 | 10.1 | 23 | 9.6 | ns | ns | ||||
| (partial) facial paralysis | 0 | 0 | 1 | 0.3 | 0 | 0 | 1 | 0.4 | ∼ | 0 | 0 | 0 | 0 | ∼ | ∼ | ||||
| itching | 3 | 1.0 | 6 | 2.0 | 2 | 15.4 | 2 | 0.8 | 32.5 | (3.8–278.6) p = 0.002 | 7 | 2.5 | 6 | 2.5 | ns | ns | |||
| tiredness | 7 | 2.2 | 5 | 1.7 | 1 | 7.7 | 2 | 0.8 | ns | 11 | 4.0 | 11 | 4.6 | ns | ns | ||||
| dizziness | 0 | 0 | 1 | 0.3 | 0 | 0 | 1 | 0.4 | ∼ | 4 | 1.4 | 4 | 1.7 | ∼ | ∼ | ||||
| swollen tick bite site | 2 | 0.6 | 4 | 1.4 | 0 | 0 | 3 | 1.2 | ∼ | 6 | 2.2 | 0 | 0 | ns | ns | ||||
EM = erythema migrans; mOR = multivariate odds ratio; CI = confidence interval; ns = not statistically significant.
*
multivariate logistic regression model, matched by case.
†
multivariate logistic regression model, adjusted for age.
‡
significantly lower risk of an indistinct rash (other than EM) at follow-up than at baseline in the multivariate logistic regression model, matched by case (odds ratio 0.5, 95%CI: 0.3–0.9, p-value 0.03).